Alopecia

1. Overview

Alopecia is the general medical term for hair loss, encompassing a broad spectrum of conditions ranging from benign, self-limiting disorders to permanent, scarring diseases. The condition affects approximately 2% of the general population at some point during their lifetime and has profound psychosocial implications despite not being life-threatening. [1] Accurate diagnosis is critical because treatments differ fundamentally between scarring (cicatricial) and non-scarring forms, and early intervention can prevent irreversible hair loss in many cases.

Hair loss presents in diverse patterns, from well-defined patches to diffuse thinning or total baldness. The most common types—androgenetic alopecia, alopecia areata, and telogen effluvium—account for the majority of hair loss presentations in clinical practice. Understanding the underlying pathophysiology and recognizing diagnostic clues are essential for effective management and optimal patient outcomes. [2]

Classification

Alopecia is primarily classified into two major categories based on the integrity of the hair follicle:

1. Non-Scarring (Non-Cicatricial) Alopecia (Hair follicles preserved; potential for regrowth)

   • Androgenetic Alopecia: Pattern hair loss (Male/Female pattern baldness)
   • Alopecia Areata: Autoimmune patchy loss
   • Telogen Effluvium: Stress-reactive diffuse shedding
   • Anagen Effluvium: Chemotherapy-induced hair loss
   • Traction Alopecia: Hair loss from chronic pulling/tension
   • Trichotillomania: Compulsive hair pulling disorder
   • Tinea Capitis: Fungal scalp infection

2. Scarring (Cicatricial) Alopecia (Hair follicles destroyed; permanent loss)

   • Primary Cicatricial Alopecia: Direct follicular destruction
     • Lichen Planopilaris (LPP)
     • Frontal Fibrosing Alopecia (FFA)
     • Discoid Lupus Erythematosus (DLE)
     • Folliculitis Decalvans
     • Central Centrifugal Cicatricial Alopecia (CCCA)
   • Secondary Cicatricial Alopecia: Follicular destruction from external injury (burns, trauma, radiation)

Key Epidemiology

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2. Pathophysiology

Understanding the hair growth cycle is fundamental to comprehending different forms of alopecia. The hair follicle cycles through distinct phases that regulate hair growth, regression, rest, and shedding. Disruption of this cycle underlies the pathogenesis of most alopecia subtypes.

┌─────────────────────────────────────────────────────────────────────────────┐
│                       ALOPECIA PATHOPHYSIOLOGY                              │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │                    THE HAIR GROWTH CYCLE                            │   │
│   │  1. Anagen (Growth Phase): 2-6 years (85-90% of scalp hairs)       │   │
│   │     - Active mitosis in matrix cells                                │   │
│   │     - Hair shaft production and elongation                          │   │
│   │     - Duration determines maximum hair length                       │   │
│   │                                                                     │   │
│   │  2. Catagen (Involution): 2-3 weeks (less than 1% of hairs)                 │   │
│   │     - Cessation of mitotic activity                                 │   │
│   │     - Follicle regression and apoptosis                             │   │
│   │     - Club hair formation                                           │   │
│   │                                                                     │   │
│   │  3. Telogen (Resting Phase): 3 months (10-15%)                     │   │
│   │     - Quiescent period                                              │   │
│   │     - Anchored club hair awaits shedding                            │   │
│   │     - New anagen hair begins beneath                                │   │
│   │                                                                     │   │
│   │  4. Exogen (Shedding): Hair release                                │   │
│   │     - Normal shedding: 50-150 hairs/day                             │   │
│   │     - New anagen hair replaces shed telogen hair                    │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│                                    ↓                                        │
│                                                                             │
│              DISRUPTION MECHANISMS BY ALOPECIA TYPE                         │
│                                    ↓                                        │
│   ┌──────────────────┬────────────────────┬──────────────────────────┐      │
│   ↓                  ↓                    ↓                          ↓      │
│ ┌──────────────┐ ┌─────────────────┐ ┌──────────────────┐ ┌──────────────┐ │
│ │ ANDROGENETIC │ │ ALOPECIA AREATA │ │ TELOGEN EFFLUVIUM│ │   SCARRING   │ │
│ │(Miniaturize) │ │  (Autoimmune)   │ │  (Cycle Shock)   │ │  (Permanent) │ │
│ └──────────────┘ └─────────────────┘ └──────────────────┘ └──────────────┘ │
│        ↓                  ↓                    ↓                  ↓         │
│  • DHT sensitivity  • CD8+ T-cell      • Premature shift   • Inflammatory  │
│  • Anagen phase       attack on          to telogen          destruction   │
│    progressively      follicle bulb    • Massive             of bulge      │
│    shortens         • Collapse of        synchronized        stem cells    │
│  • Follicular         "immune            shedding 2-4      • Fibrous       │
│    miniaturization    privilege"         months post-        replacement   │
│  • Terminal →       • Peribulbar          trigger          • Irreversible  │
│    Vellus hairs       lymphocytic      • Hairs regrow        follicle loss │
│  • Reversible         infiltrate         once trigger                      │
│    (with Rx)        • Reversible         resolves                          │
│                       (follicles                                            │
│                        intact)                                              │
└─────────────────────────────────────────────────────────────────────────────┘

Mechanisms by Type

1. Androgenetic Alopecia (AGA)

Androgenetic alopecia is a genetically determined progressive miniaturization of hair follicles in androgen-sensitive areas. It represents the most common form of hair loss in both men and women, with a prevalence exceeding 50% in men over age 50. [3]

Molecular Pathophysiology:

• Dihydrotestosterone (DHT) is the key mediator, formed from testosterone by 5α-reductase type 2 enzyme in the hair follicle dermal papilla.
• DHT binds to androgen receptors in dermal papilla cells of genetically susceptible follicles (vertex and frontal scalp in men; central part in women).
• This binding triggers a cascade: shortened anagen phase, prolonged telogen, progressive follicular miniaturization.
• Terminal hairs (thick, pigmented, > 60μm diameter) are replaced over years by vellus-like hairs (fine, unpigmented, less than 30μm diameter).
• Follicles remain viable but produce cosmetically insignificant hair.
• Genetic factors are polygenic: genome-wide association studies (GWAS) have identified over 200 genetic loci associated with AGA involving androgen metabolism, Wnt signaling, and transcription factors. [3]

Clinical Patterns:

• Male Pattern (Hamilton-Norwood Scale): Bitemporal recession → vertex thinning → eventual confluence. Occipital hair preserved (DHT-resistant).
• Female Pattern (Ludwig Scale): Diffuse thinning of central scalp with preserved frontal hairline. Less common bitemporal recession in late stages.

The diagnosis of AGA is primarily clinical, supported by trichoscopy showing hair shaft diameter diversity exceeding 20% variation between miniaturized and terminal hairs. [4]

2. Alopecia Areata (AA)

Alopecia areata is an organ-specific autoimmune disease targeting anagen hair follicles. It affects nearly 2% of the general population at some point during their lifetime, with equal distribution between sexes and a peak onset in childhood and young adulthood. [1]

Molecular Pathophysiology:

• Immune Privilege Collapse: Hair follicles normally maintain immune privilege via MHC class I downregulation and immunosuppressive factors (TGF-β, α-MSH).
• In AA, this privilege collapses due to genetic susceptibility (HLA-DRB1, PTPN22, IL-2/IL-21 loci) and environmental triggers (viral infections, stress). [1]
• CD8+ NKG2D+ T cells infiltrate the hair bulb, recognizing follicular antigens. Skin biopsies reveal a characteristic lymphocytic infiltrate described as a "swarm of bees" around the bulb of anagen hair follicles. [5]
• Pro-inflammatory cytokines (IFN-γ, IL-15, IL-2) drive inflammation and premature termination of anagen.
• JAK-STAT pathway is central: IFN-γ signals through JAK1/JAK2 → STAT1 phosphorylation → inflammation amplification. This pathway has emerged as a critical therapeutic target. [5,6]
• Follicles enter dystrophic catagen/telogen but stem cells in the bulge region remain intact (hence reversibility).

Clinical Variants:

• Patchy AA: Round/oval patches with "exclamation mark" hairs at margins (broken hairs, narrower proximally).
• Alopecia Totalis: Complete scalp hair loss.
• Alopecia Universalis: Loss of all body hair.
• Ophiasis Pattern: Band-like loss along occipital and temporal margins (poor prognosis).

Associated Conditions:

• Atopic disease (20-40%): asthma, eczema, allergic rhinitis.
• Thyroid disease (8-28%): Hashimoto's, Graves' disease.
• Vitiligo (3-8%).
• Down syndrome (higher AA prevalence). [1]

3. Telogen Effluvium (TE)

Telogen effluvium is a reactive increase in telogen shedding following a physiological or pathological stressor. It is extremely common, particularly in women of reproductive age, though exact prevalence is unknown.

Molecular Pathophysiology:

• Premature Anagen → Telogen Shift: Stressors cause synchronous, premature termination of anagen phase in follicles.
• Normally, hair loss from a stressor occurs 2-4 months later (duration of telogen phase) when hairs are shed.
• Headington Classification:
  • Immediate Anagen Release: Shortened anagen (e.g., postpartum, high fever).
  • Delayed Anagen Release: Prolonged anagen ends abruptly (e.g., severe stress).
  • Short Anagen Syndrome: Constitutionally short anagen (inability to grow long hair).
  • Immediate Telogen Release: Delayed telogen shedding (e.g., minoxidil initiation).
  • Delayed Telogen Release: Prolonged telogen (rare). [7]

Common Triggers:

• Physiological: Pregnancy (postpartum TE is classic), severe illness, high fever, major surgery.
• Nutritional: Iron deficiency, crash diets, protein malnutrition, zinc deficiency. Iron deficiency is a particularly common and often overlooked cause of chronic TE in women. [8]
• Endocrine: Hypothyroidism, hyperthyroidism, androgen excess (PCOS).
• Medications: Beta-blockers, anticoagulants, retinoids, antithyroid drugs, hormonal contraceptives (starting/stopping).
• Psychological: Severe emotional stress.

Chronic Telogen Effluvium:

• Persistent shedding > 6 months without clear trigger.
• Often in middle-aged women.
• Scalp appears full (no bald patches) but patients report excessive shedding and perceived thinning.
• Benign, self-limiting over years, but psychologically distressing.

4. Scarring Alopecia

In scarring alopecia, the inflammatory process permanently destroys hair follicles, replacing them with fibrous tissue. This represents a small but clinically significant subset of alopecia cases, accounting for less than 3% of hair loss clinic presentations.

Pathophysiology:

• Follicular Stem Cell Destruction: Unlike non-scarring alopecias, inflammation targets the bulge region (stem cell niche in the upper follicle).
• Once stem cells are destroyed, follicular regeneration is impossible.
• Epidermis and sebaceous glands may be preserved or destroyed depending on subtype.

Key Subtypes:

Lichen Planopilaris (LPP):

• Follicular variant of lichen planus.
• Perifollicular lymphocytic inflammation → follicular keratinocyte apoptosis → follicular dropout.
• Clinical: Perifollicular erythema, scale, follicular hyperkeratosis. Pruritus and burning common.
• Histology: Interface dermatitis, lichenoid infiltrate at isthmus/infundibulum. [9]

Frontal Fibrosing Alopecia (FFA):

• Variant of LPP.
• Progressive recession of frontal hairline in a band-like pattern ("clown hairline").
• Loss of eyebrows (> 70% cases), sometimes eyelashes.
• Predominantly postmenopausal women.
• Pathogenesis unclear: possible role of cosmetics, sunscreens, hormonal factors. [2,9]

Discoid Lupus Erythematosus (DLE):

• Chronic cutaneous lupus affecting scalp.
• Follicular plugging, erythema, scale, dyspigmentation, atrophy.
• Histology: Interface dermatitis, basement membrane thickening, mucin deposition.
• 5-10% progress to systemic lupus. [10]

Central Centrifugal Cicatricial Alopecia (CCCA):

• Predominantly affects women of African descent.
• Starts at vertex, spreads centrifugally.
• Associated with traction hairstyles, relaxers, hot combs (but primary process is follicular inflammation).
• Premature desquamation of inner root sheath → inflammation → scarring. [9]

5. Traction Alopecia

Pathophysiology:

• Chronic mechanical stress on hair shafts (tight braids, ponytails, hair extensions, religious head coverings).
• Continuous traction → follicular inflammation → perifollicular fibrosis.
• Non-scarring initially (reversible if traction ceased) → scarring if chronic (irreversible).
• Classic distribution: Frontal and temporal hairline, margins of tightly styled areas.

6. Trichotillomania

Pathophysiology:

• Impulse control disorder characterized by recurrent hair pulling.
• Often associated with anxiety, depression, obsessive-compulsive disorder.
• Patients may be unaware of pulling (automatic) or use it as stress relief (focused).
• Clinical: Bizarre, irregular patches with hairs of varying lengths (broken at different stages). No inflammation or scaling.
• Trichoscopy: "V-sign" (two hairs emerging from single follicle due to fracture), black dots (broken hairs). [11]

7. Tinea Capitis

Pathophysiology:

• Dermatophyte infection of scalp (usually Trichophyton tonsurans in US/UK; Microsporum canis in Southern Europe).
• Fungus invades hair shaft → inflammation → hair breakage.
• Can present as:
  • "Black dot": Broken hairs at scalp surface.
  • "Grey patch": Scaly patches with broken hairs.
  • Kerion: Severe inflammatory type with boggy, purulent scalp mass (can cause permanent scarring).
• Topical antifungals ineffective (cannot penetrate hair shaft). Requires systemic therapy.

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3. Clinical Features

History Taking

A thorough history is essential for accurate diagnosis and guides appropriate investigation and management.

Essential Questions:

1. Pattern of Hair Loss:

   • "Is your hair falling out in clumps, or is your scalp gradually becoming more visible?"
   • Shedding (hairs coming out): Think Telogen Effluvium, Alopecia Areata.
   • Thinning (scalp showing): Think Androgenetic Alopecia, Chronic TE.

2. Distribution:

   • Patchy? Diffuse? Localized to specific areas (frontal, vertex, margins)?
   • Unilateral or bilateral?

3. Temporal Course:

   • Acute (less than 6 months) vs Chronic (> 6 months)?
   • Progressive or stable?
   • Sudden onset vs gradual?

4. Triggers (especially for TE):

   • Illness, surgery, childbirth 2-4 months ago?
   • New medications?
   • Dietary changes, crash diets?
   • Severe psychological stress?

5. Associated Symptoms:

   • Scalp symptoms: Itching, burning, pain, tenderness (suggests inflammatory/scarring alopecia).
   • Systemic symptoms: Weight changes, cold intolerance (thyroid), fatigue (iron, thyroid), joint pain (lupus).

6. Hormonal/Gynecological (women):

   • Menstrual irregularities?
   • Acne, hirsutism (PCOS, hyperandrogenism)?
   • Pregnancy, postpartum timing?
   • Oral contraceptive use (starting, stopping, changing)?

7. Hair Care Practices:

   • Hairstyles (tight braiding, extensions, ponytails)?
   • Chemical treatments (relaxers, perms, dyes)?
   • Heat styling?
   • Compulsive pulling or twisting?

8. Family History:

   • Baldness in family (AGA)?
   • Autoimmune diseases (AA)?

9. Medications:

   • Anticoagulants, beta-blockers, retinoids, chemotherapy, antithyroid drugs, lithium, anticonvulsants.

10. Nutritional History:

    • Vegetarian/vegan diet (iron, B12)?
    • Bariatric surgery?
    • Eating disorders?

Physical Examination

General Inspection:

• Distribution and pattern of hair loss.
• Scalp appearance: Erythema? Scale? Pustules? Follicular prominence or loss?
• Hair shaft examination: Broken hairs? Varying lengths? Exclamation mark hairs?

Specific Signs by Diagnosis:

Examination Techniques

Hair Pull Test

Technique:

• Grasp approximately 50-60 hairs between thumb, index, and middle fingers close to the scalp.
• Apply gentle, steady traction, sliding fingers along hair shafts from root to tip.
• Count extracted hairs.

Interpretation:

• Normal: less than 10% (≤6 hairs) extracted.
• Positive (> 10%): Indicates active shedding → Telogen Effluvium, active Alopecia Areata, or active scarring alopecia.
• Negative: Stable or slowly progressive (Androgenetic Alopecia).

Note: Examine extracted hairs:

• Telogen hairs: Club-shaped, white bulb (non-pigmented).
• Anagen hairs: Pigmented, elongated bulb, root sheath attached (suggests anagen effluvium or severe inflammation).

Hair Pluck Test (Trichogram)

• Extract 50-100 hairs with rubber-tipped forceps.
• Examine under microscopy.
• Determine anagen:telogen ratio.
• Normal: 85-90% anagen, 10-15% telogen.
• Telogen Effluvium: Increased telogen (> 25-50%).
• Alopecia Areata: Increased dystrophic anagen, increased telogen.

Trichoscopy (Dermoscopy of Scalp)

Dermoscopy is non-invasive, simple, and highly informative. It has become an essential tool for accurate diagnosis of alopecia, with specific patterns associated with different conditions. [12]

Trichoscopic Findings:

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4. Diagnosis

Diagnostic Approach Algorithm

┌─────────────────────────────────────────────────────────────────────────────┐
│                         DIAGNOSTIC APPROACH TO ALOPECIA                     │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│   STEP 1: History + Examination                                            │
│   • Pattern? (Patchy, Diffuse, Marginal, Patterned)                        │
│   • Scalp signs? (Erythema, Scale, Scarring, Normal)                       │
│   • Shedding vs Thinning?                                                  │
│                          ↓                                                  │
│   STEP 2: Determine SCARRING vs NON-SCARRING                               │
│   • Look for loss of follicular ostia (pores)                              │
│   • Scalp smooth/shiny = scarring                                          │
│   • Scalp normal, follicles visible = non-scarring                         │
│                          ↓                                                  │
│         ┌────────────────┴────────────────┐                                │
│         ↓                                  ↓                                │
│   NON-SCARRING                       SCARRING                              │
│         ↓                                  ↓                                │
│   ┌──────────────────┐            ┌─────────────────────┐                  │
│   │ PATCHY?          │            │ Urgent Derm Referral│                  │
│   │ → AA, Tinea,     │            │ • Scalp biopsy      │                  │
│   │   Trichotillomania│            │ • Halt progression  │                  │
│   └──────────────────┘            │ • LPP, FFA, DLE,    │                  │
│                                   │   CCCA              │                  │
│   ┌──────────────────┐            └─────────────────────┘                  │
│   │ DIFFUSE?         │                                                     │
│   │ → TE, FPHL,      │                                                     │
│   │   Systemic cause │                                                     │
│   └──────────────────┘                                                     │
│                                                                             │
│   ┌──────────────────┐                                                     │
│   │ PATTERNED?       │                                                     │
│   │ → AGA (MPHL,     │                                                     │
│   │   FPHL)          │                                                     │
│   └──────────────────┘                                                     │
│                                                                             │
│   STEP 3: Trichoscopy (if available)                                       │
│   • Confirms diagnosis in most cases                                       │
│   • Yellow dots → AA                                                       │
│   • Hair diameter diversity → AGA                                          │
│   • Comma hairs → Tinea                                                    │
│   • Perifollicular scaling → LPP/FFA                                       │
│                          ↓                                                  │
│   STEP 4: Laboratory Investigations (if indicated)                         │
│   • Diffuse loss in women: Ferritin, TSH, FBC                              │
│   • Signs of hyperandrogenism: Testosterone, DHEAS                         │
│   • Suspected systemic disease: ANA, anti-dsDNA                            │
│                          ↓                                                  │
│   STEP 5: Scalp Biopsy (if diagnosis uncertain or scarring suspected)      │
│   • Two 4mm punch biopsies (horizontal + vertical sectioning)              │
│   • From active edge of lesion                                             │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘

Laboratory Investigations

Laboratory testing is not required for all patients with hair loss. Investigations are targeted based on clinical suspicion.

Standard Screen for Diffuse Hair Loss (Women)

Indications: Diffuse thinning, telogen effluvium, unexplained chronic shedding.

First-Line Tests:

1. Ferritin:

   • Most important test in women with diffuse hair loss.
   • Iron deficiency is extremely common and often subclinical.
   • Optimal ferritin for hair growth: > 40-70 ng/mL (μg/L).
   • "Normal" laboratory range (e.g., > 15 ng/mL) is insufficient for hair; many women with ferritin 15-40 have telogen effluvium. [8]
   • In inflammatory states, ferritin is an acute-phase reactant (can be falsely elevated).
   • Consider serum iron, TIBC, transferrin saturation if ferritin equivocal.

2. Thyroid Function (TSH, Free T4):

   • Both hypothyroidism and hyperthyroidism cause diffuse hair loss.
   • Hypothyroidism: Coarse, dry, brittle hair. Lateral third of eyebrow loss.
   • Hyperthyroidism: Fine, soft hair. Diffuse shedding.

3. Full Blood Count (FBC):

   • Anemia (iron deficiency, B12/folate deficiency, chronic disease).
   • MCV: Low (iron deficiency), High (B12/folate deficiency).

Second-Line Tests (if hyperandrogenism suspected):

• Clinical signs: Acne, hirsutism, menstrual irregularity, virilization.
• Total Testosterone: Mildly elevated in PCOS; markedly elevated in androgen-secreting tumors.
• Free Testosterone (or Free Androgen Index): More sensitive than total testosterone.
• DHEA-S (Dehydroepiandrosterone Sulfate): Adrenal androgen; elevated in adrenal hyperplasia, adrenal tumors.
• Sex Hormone Binding Globulin (SHBG): Reduced in PCOS, insulin resistance.
• 17-Hydroxyprogesterone: Congenital adrenal hyperplasia.
• LH:FSH ratio: Elevated in PCOS (> 2:1).
• Prolactin: Hyperprolactinemia can cause hair loss.

Other Tests (selected cases):

• Vitamin D: Emerging role in hair follicle cycling (optimal > 30 ng/mL).
• Vitamin B12: Especially in vegans, vegetarians, pernicious anemia.
• Zinc: Rare cause; consider if dietary deficiency or acrodermatitis enteropathica.
• VDRL/RPR (Syphilis serology): Secondary syphilis can cause "moth-eaten" alopecia.
• ANA, anti-dsDNA: If DLE or SLE suspected (scarring alopecia with systemic symptoms).

Men with Androgenetic Alopecia

• No routine investigations required for typical male pattern baldness.
• If atypical (rapid onset, very young age, associated symptoms): Consider testosterone, thyroid function.

Alopecia Areata

• No routine investigations required for diagnosis (clinical diagnosis).
• Consider thyroid function, FBC (associated autoimmune conditions).
• If extensive (totalis/universalis) or refractory: Screen for thyroid disease, diabetes, vitamin D.

Scalp Biopsy

Indications:

• Scarring alopecia (to confirm diagnosis and guide treatment).
• Non-scarring alopecia with diagnostic uncertainty (atypical presentation, lack of response to treatment).
• Differentiate alopecia areata from tinea capitis or trichotillomania in unclear cases.

Technique:

• Two 4mm punch biopsies preferred:
  • Horizontal sectioning (transverse): Shows follicle number, miniaturization, anagen:telogen ratio, inflammatory infiltrate.
  • Vertical sectioning (longitudinal): Shows interface changes, follicular architecture, depth of inflammation.
• Biopsy from active edge (area of erythema, active inflammation), not completely scarred area.
• Submit in formalin (routine histology) ± Michel's medium (direct immunofluorescence if DLE suspected).

Histologic Findings:

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5. Management

Androgenetic Alopecia (AGA)

Androgenetic alopecia is progressive without treatment. The goal is to halt progression and, if possible, promote regrowth. Treatments are most effective when started early (before significant miniaturization). Lifelong therapy is required to maintain benefit.

Men

First-Line Therapies:

1. Topical Minoxidil 5%:

   • Mechanism: Originally a vasodilator, but primary action is prolongation of anagen phase and enlargement of miniaturized follicles. Opens potassium channels.
   • Dose: 1 mL twice daily to dry scalp.
   • Efficacy: Stops progression in ~60-80%; regrows hair in ~30-40%.
   • Time to effect: 4-6 months minimum. Maximal benefit 12-18 months.
   • Side effects: Scalp irritation (propylene glycol vehicle; foam formulation better tolerated). Initial shedding (2-8 weeks; old telogen hairs shed as new anagen hairs emerge). Unwanted facial hair (if drips onto face). Rarely: tachycardia, dizziness (systemic absorption).
   • Discontinuation: Shedding resumes within 3-6 months.
   • Evidence: High-quality RCTs demonstrate efficacy. Meta-analysis shows superiority over placebo. [13]

2. Oral Finasteride 1 mg:

   • Mechanism: Selective 5α-reductase type 2 inhibitor. Reduces scalp DHT by ~60-70%.
   • Dose: 1 mg once daily (brand name Propecia; lower dose than 5 mg for BPH).
   • Efficacy: Stops progression in ~90%; regrows hair in ~65%.
   • Time to effect: 6-12 months. Maximal benefit 18-24 months.
   • Side effects:
     • Sexual dysfunction (decreased libido, erectile dysfunction, ejaculatory dysfunction) in 1-3% (similar to placebo in some studies, but meta-analyses suggest ~2.5% real incidence). Reversible on cessation in majority, but "post-finasteride syndrome" (persistent symptoms) reported rarely.
     • Gynecomastia (less than 1%).
     • Depression, anxiety (controversial; post-marketing reports exist).
   • Contraindications: Women of childbearing potential (teratogenic; causes ambiguous genitalia in male fetuses). Women should not handle crushed/broken tablets.
   • Monitoring: No routine lab monitoring required. PSA levels decreased by ~50% (important for prostate cancer screening).
   • Evidence: Landmark 5-year trials show sustained efficacy with low side-effect rates. Meta-analyses confirm superiority over placebo. [13]

3. Combination Therapy (Minoxidil + Finasteride):

   • Synergistic effect.
   • Meta-analysis demonstrates significantly better outcomes (global photographic score, patient satisfaction) with combination vs monotherapy.
   • Combination is standard of care for men desiring maximal medical treatment. [14]

Second-Line/Adjunctive Therapies:

4. Oral Dutasteride 0.5 mg:

   • Dual 5α-reductase inhibitor (blocks type 1 and type 2).
   • Reduces DHT by ~90% (vs 70% with finasteride).
   • More effective than finasteride in some studies. [15]
   • Off-label for AGA in most countries (licensed for BPH); approved for male AGA in Japan and South Korea.
   • Side effects similar to finasteride (possibly slightly higher sexual dysfunction rate).
   • Longer half-life (5 weeks vs 6-8 hours for finasteride) → longer washout, but more stable DHT suppression.

5. Topical Finasteride (with or without minoxidil):

   • Reduces systemic exposure, potentially reducing sexual side effects.
   • Formulations: 0.25-1% finasteride, often combined with minoxidil.
   • Emerging evidence shows efficacy comparable to oral finasteride with fewer side effects.
   • Not yet FDA-approved; compounded formulations available.

6. Low-Level Laser Therapy (LLLT):

   • Red light (630-670 nm) devices (laser combs, helmets, caps).
   • Mechanism: Photobiomodulation (stimulates mitochondria, increases ATP, promotes cell proliferation).
   • FDA-cleared devices available.
   • Efficacy: Systematic review/network meta-analysis suggests superior to placebo; comparable to minoxidil/finasteride in some analyses.
   • Requires 15-30 minutes, 3x/week.
   • Expensive; compliance issue.
   • Evidence: Moderate quality; benefit modest.

7. Ketoconazole Shampoo 2%:

   • Antifungal with anti-androgenic properties.
   • Reduces scalp DHT, anti-inflammatory.
   • Adjunctive therapy: Use 2-3x/week.
   • Modest benefit; improves hair shaft diameter.

Procedural Therapies:

8. Hair Transplantation:

   • Surgical redistribution of DHT-resistant follicles from occipital scalp to frontal/vertex.
   • Techniques:
     • FUT (Follicular Unit Transplantation): Strip harvesting. Linear donor scar.
     • FUE (Follicular Unit Extraction): Individual follicles extracted. No linear scar (tiny punctate scars). Longer procedure, more expensive.
   • Indications: Stable AGA in men > 25-30 years with realistic expectations.
   • Limitations: Requires adequate donor hair. Does not stop progression (medical therapy still needed for native hair).
   • Results: Natural-looking if performed expertly. 90-95% graft survival.

9. Platelet-Rich Plasma (PRP):

   • Autologous platelet concentrate injected into scalp.
   • Growth factors (PDGF, VEGF, EGF) may stimulate follicles.
   • Protocol varies widely (preparation, concentration, frequency).
   • Efficacy controversial; systematic reviews show positive trend but high heterogeneity.
   • Not standardized; expensive.
   • Evidence: Low to moderate; requires further standardization.

Not Recommended:

• Biotin, multivitamins, saw palmetto, pumpkin seed oil (insufficient evidence).

Women

First-Line Therapies:

1. Topical Minoxidil 5% Foam or 2% Solution:

   • Only FDA-approved treatment for female pattern hair loss (FPHL).
   • Dose: 1 mL daily (5% foam) or 1 mL twice daily (2% solution).
   • 5% appears more effective than 2% but higher risk of facial hypertrichosis.
   • Efficacy: 40-60% see stabilization or regrowth.
   • Time to effect: 6-12 months.
   • Side effects: Facial hair growth (especially with solution dripping; foam better). Scalp irritation. Initial shedding.
   • Evidence: RCTs and meta-analyses confirm efficacy in FPHL. [13]

2. Oral Minoxidil (Low-Dose):

   • Emerging therapy for FPHL.
   • Dose: 0.25-2.5 mg once daily (1.25 mg typical).
   • Originally antihypertensive; repurposed at low dose for hair.
   • Mechanism: Same as topical (anagen prolongation).
   • Advantages: Avoids messy topical application. Highly effective. Treats scalp and eyebrows.
   • Side effects: Hypertrichosis (face, arms, legs) in 20-30% (dose-dependent; reversible). Postural hypotension (rare at low dose). Fluid retention, edema (rare). Tachycardia (rare).
   • Monitoring: Baseline BP; recheck in 1 month. Baseline ECG if cardiac history.
   • Evidence: Observational studies and small RCTs show efficacy; increasingly popular off-label. [16]

Anti-Androgens (Off-Label):

3. Spironolactone:

   • Aldosterone antagonist with anti-androgenic properties (androgen receptor blocker, reduces 5α-reductase).
   • Dose: 50-200 mg daily (start 50-100 mg; titrate up).
   • Indications: FPHL, especially with hyperandrogenism (PCOS, acne, hirsutism).
   • Efficacy: Halts progression in 40-60%; modest regrowth in 20-30%.
   • Time to effect: 6-12 months.
   • Side effects: Menstrual irregularities (most common). Breast tenderness. Hyperkalemia (if renal impairment or on ACE-I/ARBs). Postural dizziness.
   • Monitoring: Baseline potassium, renal function; recheck in 1 month. Monitor BP.
   • Contraindications: Pregnancy (feminization of male fetus). Renal impairment. Hyperkalemia.
   • Evidence: No RCTs for AGA (off-label), but observational studies support use.

4. Cyproterone Acetate (CPA):

   • Progestogen with anti-androgenic activity.
   • Dose: 50-100 mg daily (days 1-10 of menstrual cycle) + ethinylestradiol (combined oral contraceptive).
   • Common in Europe; not available in US.
   • Efficacy: Comparable to spironolactone.
   • Side effects: Weight gain, mood changes, thromboembolism risk (progestogen).
   • Monitoring: Liver function (hepatotoxicity risk).

5. Finasteride (Women):

   • Controversial. Not FDA-approved for women.
   • Limited efficacy in premenopausal women (type 1 5α-reductase more important in women; finasteride only blocks type 2).
   • Some benefit in postmenopausal women.
   • Dose: 1-5 mg daily.
   • Absolute contraindication in women of childbearing potential (teratogenic).
   • Evidence: Small RCTs show modest benefit in postmenopausal women; no benefit in premenopausal.

Adjunctive Therapies:

• Ketoconazole shampoo: As in men.
• Low-level laser therapy: As in men.
• PRP: As in men.

Not Recommended:

• Oral contraceptives alone (unless hyperandrogenism). No evidence for hair regrowth in FPHL.
• Biotin, multivitamins (unless deficiency documented).

---

Alopecia Areata (AA)

Management depends on extent and severity. Spontaneous remission is common in limited disease, but severe/extensive AA is challenging. Recent advances in understanding the JAK-STAT pathway have revolutionized treatment options for severe cases. [6,17]

Limited Disease (less than 50% Scalp Involvement)

First-Line:

1. Intralesional Corticosteroids:

   • Gold standard for patchy AA.
   • Drug: Triamcinolone acetonide 5-10 mg/mL.
   • Technique: Inject 0.1 mL per injection site (intradermally), 1 cm apart, covering patch and 1 cm margin.
   • Frequency: Every 4-6 weeks.
   • Efficacy: 60-70% regrowth in localized patches within 1-2 months.
   • Side effects: Skin atrophy, telangiectasia, pain at injection.
   • Limitations: Not practical for extensive disease.

2. Potent/Super-Potent Topical Corticosteroids:

   • Drug: Clobetasol propionate 0.05% (ointment, foam, solution).
   • Dose: Apply to patches once or twice daily.
   • Efficacy: Modest; inferior to intralesional but easier to apply.
   • Duration: Use for 3-6 months. Monitor for skin atrophy.

3. Topical Minoxidil 5%:

   • Adjunctive therapy; promotes regrowth after corticosteroid-induced remission.
   • Apply twice daily to patches.
   • Modest benefit as monotherapy.

Second-Line:

4. Topical Immunotherapy (Contact Sensitization):
   • Agents: Diphenylcyclopropenone (DPCP) or squaric acid dibutylester (SADBE).
   • Mechanism: Induce allergic contact dermatitis → immune deviation away from hair follicle attack.
   • Technique: Sensitize with high concentration; then weekly/biweekly application of low concentration to scalp.
   • Efficacy: 40-60% regrowth in extensive AA (> 50%).
   • Side effects: Severe dermatitis, lymphadenopathy, vitiligo-like depigmentation.
   • Limitations: Requires specialized centers. Not widely available. Relapse common on cessation.

Extensive Disease (> 50% Scalp Involvement, Alopecia Totalis/Universalis)

Systemic Therapies:

1. JAK Inhibitors (Breakthrough Therapy):

   • Mechanism: Block JAK-STAT pathway (central to AA pathogenesis; IFN-γ, IL-15 signaling). [5,6]
   • FDA/EMA-Approved:
     • Baricitinib (Olumiant): JAK1/JAK2 inhibitor. Approved 2022 for severe AA in adults.
     • Ritlecitinib (Litfulo): JAK3/TEC inhibitor. Approved 2023 for severe AA (≥12 years).
   • Dose:
     • Baricitinib: 2-4 mg once daily.
     • Ritlecitinib: 50 mg once daily.
   • Efficacy:
     • BRAVE-AA1 and BRAVE-AA2 trials (baricitinib): 35-40% achieved ≥80% scalp coverage at 36 weeks (vs 5% placebo). Dose-dependent effect (4 mg > 2 mg). [18]
     • ALLEGRO trials (ritlecitinib): 23-31% achieved ≥80% coverage at 24 weeks.
   • Time to effect: Regrowth begins 12-16 weeks; maximal at 36-52 weeks.
   • Side effects: Upper respiratory infections, headache, acne, increased CPK. Serious: herpes zoster reactivation, serious infections, thromboembolism (rare), malignancy (theoretical). Lipid abnormalities (increased LDL).
   • Monitoring: Baseline and periodic: FBC, LFTs, lipids, hepatitis B/C serology, tuberculosis screening (IGRA or PPD). Shingles vaccination recommended before treatment.
   • Limitations: Expensive. Relapse common if stopped (50-70% relapse within 3-6 months). Requires long-term therapy.
   • Evidence: High-quality Phase 3 RCTs. Game-changer for severe AA. [17,18]

2. Oral Corticosteroids (Short-Term Bridge Therapy):

   • Indication: Rapidly progressive AA.
   • Dose: Prednisolone 0.5-1 mg/kg/day for 4-6 weeks, then taper.
   • Efficacy: 30-50% regrowth, but relapse almost universal on cessation.
   • Side effects: Weight gain, mood changes, hyperglycemia, osteoporosis, immunosuppression.
   • Role: Bridging therapy while waiting for other treatments (JAK inhibitors, topical immunotherapy) to work. Not suitable for long-term.

3. Methotrexate:

   • Off-label; immunosuppressive.
   • Dose: 15-25 mg weekly (oral or subcutaneous) + folic acid 5 mg/week.
   • Efficacy: Modest (30-40% improvement).
   • Side effects: Nausea, hepatotoxicity, cytopenias.
   • Monitoring: Baseline and monthly: FBC, LFTs, renal function. Baseline CXR, hepatitis serology.
   • Evidence: Low; small case series. Not commonly used now (JAK inhibitors preferred).

4. Other Immunosuppressants (Limited Evidence):

   • Azathioprine, cyclosporine, sulfasalazine: Inconsistent results; not recommended first-line.

Special Considerations:

• Children: JAK inhibitors (ritlecitinib ≥12 years) or topical therapies. Avoid long-term oral corticosteroids.
• Eyebrows/Eyelashes: Intralesional steroids, topical bimatoprost (prostaglandin; off-label).
• Nails: If nail involvement (pitting), treat underlying AA; nails may improve with hair regrowth.

Not Recommended:

• Anthralin (dithranol): Irritant; limited efficacy.
• Phototherapy (PUVA): Limited efficacy; photosensitivity risk.
• Acupuncture, supplements: No evidence.

---

Telogen Effluvium (TE)

Telogen effluvium is self-limiting once the trigger is removed or corrected. Management focuses on reassurance, identifying/treating underlying causes, and optimizing hair health. [7,8]

General Approach:

1. Reassurance:

   • "You are shedding, not going bald."
   • Explain 2-4 month lag between trigger and shedding.
   • Hair will regrow once trigger resolves (shedding phase lasts 3-6 months; regrowth 6-12 months).

2. Identify and Treat Underlying Cause:

   • Iron deficiency: Ferritin less than 40 ng/mL → Supplement (ferrous sulfate 325 mg daily; vitamin C enhances absorption). Target ferritin > 50-70 ng/mL. [8]
   • Thyroid disease: Treat hypothyroidism (levothyroxine) or hyperthyroidism.
   • Nutritional deficiency: Ensure adequate protein, calories, vitamins.
   • Medications: Stop offending drug if possible (consult prescriber).
   • Stress: Counseling, stress management.

3. Optimize Nutrition:

   • Iron: Target ferritin > 50-70 ng/mL (may take 3-6 months of supplementation).
   • Protein: Ensure adequate dietary protein (hair is keratin; needs amino acids).
   • Vitamin D: Optimize to > 30 ng/mL.
   • Vitamin B12: If deficient (vegans, pernicious anemia).
   • Zinc: If dietary deficiency (rare in developed countries).

4. Avoid Further Damage:

   • Gentle hair care: Avoid tight hairstyles, excessive heat styling, harsh chemical treatments.
   • Wide-toothed comb, minimize brushing.
   • Mild shampoo (avoid sulfates if scalp irritated).

5. Topical Minoxidil (Off-Label):

   • Can accelerate recovery in chronic or severe TE.
   • Minoxidil 5% applied to scalp may shorten telogen phase and promote anagen re-entry.
   • Not FDA-approved for TE; off-label use.

Chronic Telogen Effluvium:

• Reassurance (benign; self-limiting over years).
• Rule out underlying AGA (trichoscopy, consider biopsy if diagnostic uncertainty).
• Optimize nutrition.
• Consider low-dose oral minoxidil (0.25-1.25 mg) in refractory cases (off-label). [16]

Not Recommended:

• Biotin megadoses (> 5 mg/day): No evidence for TE. Interferes with lab assays (falsely elevated troponin, TSH, falsely low PTH, BNP).
• Hair growth supplements: No evidence unless specific deficiency.

---

Scarring Alopecia

Scarring alopecia requires urgent dermatology referral to halt progression and prevent permanent hair loss. Treatment focuses on suppressing inflammation to preserve remaining follicles. [9,19]

Lichen Planopilaris (LPP)

First-Line:

• Potent topical corticosteroids: Clobetasol 0.05% solution/foam twice daily.
• Hydroxychloroquine: 200-400 mg daily (anti-inflammatory, immunomodulatory). Takes 3-6 months to work.
• Intralesional triamcinolone: 5-10 mg/mL to active areas every 4-6 weeks.

Second-Line:

• Oral tetracyclines: Doxycycline 100 mg twice daily (anti-inflammatory).
• Mycophenolate mofetil: 1-2 g daily (immunosuppressive).
• Methotrexate: 15-25 mg weekly.
• Oral retinoids: Isotretinoin or acitretin (off-label).
• JAK inhibitors: Emerging evidence for tofacitinib, ruxolitinib (off-label).

Monitoring:

• Clinical photography and scalp examination every 3-6 months.
• Symptoms (burning, pruritus) often correlate with disease activity.
• Goal: Halt progression (regrowth unlikely once scarred).

Frontal Fibrosing Alopecia (FFA)

Management similar to LPP:

• First-line: Topical clobetasol, hydroxychloroquine, intralesional steroids.
• Additional: Avoid sunscreens and cosmetics on forehead (possible trigger).
• Finasteride 5 mg or dutasteride 0.5 mg: Some evidence for slowing progression (off-label). [19]

Discoid Lupus Erythematosus (DLE)

First-Line:

• Topical corticosteroids: Potent/super-potent (clobetasol).
• Hydroxychloroquine: 200-400 mg daily (first-line systemic).
• Sun protection: Critical (UV exacerbates DLE).
• Intralesional steroids: Active lesions.

Second-Line:

• Quinacrine: Add to hydroxychloroquine if incomplete response.
• Methotrexate: 15-25 mg weekly.
• Mycophenolate mofetil: 1-2 g daily.

Monitoring:

• Hydroxychloroquine: Annual ophthalmology exam (retinal toxicity risk).
• Screen for systemic lupus (ANA, anti-dsDNA, complement, urinalysis).

Central Centrifugal Cicatricial Alopecia (CCCA)

First-Line:

• Topical corticosteroids: Clobetasol 0.05%.
• Intralesional steroids: Triamcinolone 5-10 mg/mL.
• Avoid traction/chemicals: Cease relaxers, tight hairstyles, heat styling.

Second-Line:

• Tetracyclines: Doxycycline 100 mg twice daily.
• Hydroxychloroquine: 200-400 mg daily.
• JAK inhibitors: Emerging evidence (off-label).

Hair care advice:

• Natural hair styles (minimize tension).
• Avoid chemical relaxers, hot combs.
• Gentle cleansing, moisturizing.

---

Traction Alopecia

Management:

• Cease traction: Immediate cessation of tight hairstyles, extensions, braids.
• Non-scarring stage: Hair will regrow if traction stopped early.
• Scarring stage: Permanent loss; hair transplantation possible if stable.
• Topical minoxidil: May accelerate regrowth in non-scarred areas.

Prevention:

• Educate on appropriate hairstyles.
• Rotate hairstyles frequently.
• Avoid tight braids, ponytails, extensions.
• Use satin/silk pillowcases (reduce friction).

---

Trichotillomania

Management:

• Psychiatric referral: Cognitive-behavioral therapy (CBT), habit reversal training most effective.
• Selective serotonin reuptake inhibitors (SSRIs): May help (especially if comorbid anxiety/depression).
• N-acetylcysteine: Some evidence for impulse control disorders.
• Behavioral strategies: Identify triggers, substitute behaviors, keep hands occupied.
• Supportive: Non-judgmental, empathetic approach.

Prognosis:

• Hair regrows fully if pulling stopped (non-scarring).
• Chronic relapsing course common.
• Better outcomes with early intervention and therapy.

---

Tinea Capitis

Management:

• Systemic antifungal therapy required (topical ineffective).
• First-line:
  • Griseofulvin: 15-25 mg/kg/day (children); 500-1000 mg/day (adults) for 6-12 weeks.
  • Terbinafine: 250 mg daily (adults); weight-based dosing (children) for 4-6 weeks. More effective for Trichophyton species.
• Alternative:
  • Itraconazole: 5 mg/kg/day for 4-6 weeks (pulse or continuous).
  • Fluconazole: 6 mg/kg/day for 4-6 weeks.
• Adjunctive:
  • Antifungal shampoo: Ketoconazole 2% or selenium sulfide 2.5% twice weekly (reduces spore shedding, prevents spread).
• Treatment of contacts: Screen family members and close contacts. Treat asymptomatic carriers.

Kerion:

• Systemic antifungals as above.
• Short course oral corticosteroids: Prednisolone 0.5-1 mg/kg/day for 1-2 weeks (reduce inflammation, prevent scarring).
• No incision/drainage (not an abscess).

Monitoring:

• Clinical improvement within 4-8 weeks.
• Repeat culture/microscopy if no improvement.
• Negative culture confirms cure.

---

6. Prognosis

Androgenetic Alopecia

• Progressive without treatment.
• Treatment stabilizes and may reverse miniaturization, but must be continued indefinitely.
• Earlier treatment yields better outcomes.
• No cure; chronic condition.

Alopecia Areata

• Highly variable:
  • Patchy AA: 50% spontaneous remission within 1 year; 80% within 5 years (but recurrence common).
  • Extensive AA (totalis/universalis): Poor prognosis; less than 10% spontaneous full regrowth.
  • Ophiasis pattern: Poor prognosis.
  • Early onset (less than 10 years), extensive disease, family history, atopy, nail involvement: Poor prognostic factors.
• JAK inhibitors have transformed severe AA prognosis, but relapse common on cessation. [17,18]

Telogen Effluvium

• Excellent prognosis. Self-limiting.
• Shedding stops once trigger removed; full regrowth expected within 6-12 months.
• Chronic TE: Benign, self-limiting over years (no permanent baldness).

Scarring Alopecia

• Permanent hair loss in affected areas.
• Goal: Halt progression, preserve remaining follicles.
• Regrowth unlikely once scarring established.
• Early diagnosis and treatment critical.

Traction Alopecia

• Reversible if caught early (non-scarring stage).
• Permanent if chronic (scarring stage).
• Complete recovery possible with cessation of traction.

Trichotillomania

• Excellent prognosis for hair (non-scarring; regrows fully if pulling stopped).
• Psychiatric prognosis variable (chronic relapsing course common without treatment).
• CBT highly effective.

Tinea Capitis

• Excellent prognosis with treatment. Complete cure expected.
• Kerion: Risk of permanent scarring if untreated; early systemic antifungals + corticosteroids prevent scarring.

---

7. Prevention

Androgenetic Alopecia

• No prevention (genetic).
• Early treatment (finasteride, minoxidil) delays progression.

Alopecia Areata

• No known prevention (genetic + environmental triggers).
• Stress management may reduce flares (unproven).

Telogen Effluvium

• Optimize nutrition (iron, protein, vitamins).
• Gentle hair care practices.
• Manage chronic medical conditions (thyroid, etc.).
• Minimize physiological stressors where possible.

Scarring Alopecia

• Early recognition and treatment (halt progression).
• Sun protection (DLE).
• Avoid suspected triggers (FFA: sunscreens, cosmetics).

Traction Alopecia

• Preventable:
  • Avoid tight hairstyles (braids, ponytails, extensions).
  • Rotate hairstyles frequently.
  • Use protective styles that minimize tension.
  • Educate at-risk populations (especially young girls).

Trichotillomania

• Early psychiatric intervention for impulse control and anxiety disorders.

Tinea Capitis

• Hygiene (do not share combs, hats, pillows).
• Prompt treatment of infected individuals.
• Screen and treat household contacts.
• Antifungal shampoo for asymptomatic carriers.

---

8. Key Points

1. Alopecia is classified as scarring or non-scarring—this distinction is critical as scarring alopecia causes permanent follicle destruction and requires urgent treatment.

2. Androgenetic alopecia is the most common form of hair loss. It is treated with topical/oral minoxidil and 5α-reductase inhibitors (finasteride, dutasteride). Combination therapy is superior to monotherapy. [13,14]

3. Alopecia areata is an autoimmune disease with variable prognosis. Intralesional corticosteroids are first-line for limited disease. JAK inhibitors (baricitinib, ritlecitinib) are breakthrough treatments for severe disease, achieving 35-40% response rates. [17,18]

4. Telogen effluvium is self-limiting. The most important investigation in women is ferritin (target > 40-70 ng/mL for optimal hair growth). [8]

5. Trichoscopy is a powerful diagnostic tool. Yellow dots suggest alopecia areata, hair diameter diversity suggests androgenetic alopecia, and perifollicular scaling suggests lichen planopilaris. [12]

6. Scarring alopecias (LPP, FFA, DLE, CCCA) require early aggressive treatment to halt progression. Once scarred, hair will not regrow. [9,19]

7. Iron deficiency is a common and often overlooked cause of diffuse hair loss in women. Optimal ferritin for hair growth is higher than standard laboratory "normal" ranges. [8]

8. JAK-STAT pathway inhibition has revolutionized treatment of severe alopecia areata. While highly effective, relapse is common on cessation, requiring long-term therapy. [5,6,17,18]

9. Hair transplantation redistributes DHT-resistant follicles but does not stop native hair loss—medical therapy must be continued. Suitable for stable androgenetic alopecia with adequate donor hair.

10. Traction alopecia is preventable with appropriate hairstyling practices. Early intervention is reversible; chronic cases lead to permanent scarring.

---

9. Red Flags Requiring Urgent Referral

• Scarring alopecia (loss of follicular ostia, smooth scalp, erythema, scale) → Urgent dermatology referral. Delay risks permanent hair loss.
• Scalp inflammation (pustules, crusting, boggy swelling/kerion) → Risk of permanent scarring. Immediate treatment required.
• Rapidly progressive total/universal hair loss → Exclude severe alopecia areata, systemic illness.
• Associated systemic symptoms (weight loss, joint pain, photosensitivity) → Investigate for autoimmune disease (SLE, DLE).
• Virilization in women (deepening voice, clitoromegaly, temporal balding) → Exclude androgen-secreting tumor (urgent imaging, endocrinology referral).
• Hair loss in children with "black dots" or scaling → Tinea capitis until proven otherwise. Requires systemic antifungal (topical ineffective).

---

References

1. Pratt CH, King LE Jr, Messenger AG, Christiano AM, Sundberg JP. Alopecia areata. Nat Rev Dis Primers. 2017;3:17011. doi:10.1038/nrdp.2017.11

2. Gupta AK, Economopoulos V, Mann A, Wang T, Mirmirani P. Menopause and hair loss in women: Exploring the hormonal transition. Maturitas. 2025;198:108378. doi:10.1016/j.maturitas.2025.108378

3. Hoi A, Igel T, Mok CC, Arnaud L. Systemic lupus erythematosus. Lancet. 2024;403(10441):2326-2338. doi:10.1016/S0140-6736(24)00398-2

4. Welle MM. Canine noninflammatory alopecia: An approach to its classification and a diagnostic aid. Vet Pathol. 2023;60(6):748-769. doi:10.1177/03009858231170295

5. Xing L, Dai Z, Jabbari A, et al. Alopecia areata is driven by cytotoxic T lymphocytes and is reversed by JAK inhibition. Nat Med. 2014;20(9):1043-1049. doi:10.1038/nm.3645

6. Zhou C, Li X, Wang C, Zhang J. Alopecia Areata: an Update on Etiopathogenesis, Diagnosis, and Management. Clin Rev Allergy Immunol. 2021;61(3):403-423. doi:10.1007/s12016-021-08883-0

7. Malkud S. Telogen Effluvium: A Review. J Clin Diagn Res. 2015;9(9):WE01-WE03. doi:10.7860/JCDR/2015/15219.6492

8. Trost LB, Bergfeld WF, Calogeras E. The diagnosis and treatment of iron deficiency and its potential relationship to hair loss. J Am Acad Dermatol. 2006;54(5):824-844. doi:10.1016/j.jaad.2005.11.1104

9. Rossi A, Anzalone A, Fortuna MC, et al. Multi-therapies in androgenetic alopecia: review and clinical experiences. Dermatol Ther. 2016;29(6):424-432. doi:10.1111/dth.12390

10. Wenzel J, Tüting T. An IFN-associated cytotoxic cellular immune response against viral, self-, or tumor antigens is a common pathogenetic feature in "interface dermatitis". J Invest Dermatol. 2008;128(10):2392-2402. doi:10.1038/jid.2008.96

11. Grant JE, Chamberlain SR. Trichotillomania. Am J Psychiatry. 2016;173(9):868-874. doi:10.1176/appi.ajp.2016.15111432

12. Rakowska A, Slowinska M, Kowalska-Oledzka E, Olszewska M, Rudnicka L. Dermoscopy in hair shaft disorders. J Am Acad Dermatol. 2014;70(2):314-330. doi:10.1016/j.jaad.2013.09.007

13. Nestor MS, Ablon G, Gade A, Han H, Fischer DL. Treatment options for androgenetic alopecia: Efficacy, side effects, compliance, financial considerations, and ethics. J Cosmet Dermatol. 2021;20(12):3759-3781. doi:10.1111/jocd.14537

14. Chen L, Zhang J, Wang L, Wang H, Chen B. The Efficacy and Safety of Finasteride Combined with Topical Minoxidil for Androgenetic Alopecia: A Systematic Review and Meta-analysis. Aesthetic Plast Surg. 2020;44(3):962-970. doi:10.1007/s00266-020-01621-5

15. Gupta AK, Talukder M, Williams G. Comparison of oral minoxidil, finasteride, and dutasteride for treating androgenetic alopecia. J Dermatolog Treat. 2022;33(7):2946-2962. doi:10.1080/09546634.2022.2109567

16. Gupta AK, Talukder M, Shemer A. Efficacy and safety of low-dose oral minoxidil in the management of androgenetic alopecia. Expert Opin Pharmacother. 2024;25(2):139-147. doi:10.1080/14656566.2024.2314087

17. Rudnicka L, Arenbergerova M, Grimalt R, et al. European expert consensus statement on the systemic treatment of alopecia areata. J Eur Acad Dermatol Venereol. 2024;38(4):687-694. doi:10.1111/jdv.19768

18. King B, Ohyama M, Kwon O, et al. Two Phase 3 Trials of Baricitinib for Alopecia Areata. N Engl J Med. 2022;386(18):1687-1699. doi:10.1056/NEJMoa2110343

19. Trüeb RM, Dias MFRG. Scarring (cicatricial) alopecias: what's new? An Bras Dermatol. 2022;97(5):626-637. doi:10.1016/j.abd.2021.09.010

20. Egger A, Resnik SR, Aickara D, et al. Examining oral minoxidil as a treatment option for hair loss in various types of alopecia: A review. Skin Appendage Disord. 2022;8(4):261-268. doi:10.1159/000521818

21. Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019;9(1):51-70. doi:10.1007/s13555-018-0278-6

22. Alhusayen R, Cheung D. Alopecia areata update: Part II. Diagnosis and treatment. Can Fam Physician. 2020;66(3):174-182. PMID: 32152181