Tinea and fungal skin infection — formative SAQs

SAQ 1 — The scaly bald scalp patch (10 marks, 15 minutes)

A five-year-old boy presents with a three-week history of an itchy, scaly, gradually enlarging bald patch on his scalp. On examination there is a four-centimetre patch of hair loss with broken hair stubs and black dots flush with the skin, mild scaling, and a firm enlarged occipital lymph node. Potassium hydroxide microscopy of a plucked hair shows branching septate hyphae and arthroconidia. [1]

a) What is the diagnosis, and which two clinical features distinguish it from alopecia areata? (2 marks) [1]

b) State the definitive treatment principle for this condition and explain why a topical antifungal cream alone cannot work. (2 marks) [2]

c) Fungal culture returns Trichophyton tonsurans. Name the preferred oral antifungal for this species and give the weight-banded daily dose for a 22 kg child, with the duration. Justify the species-specific choice using the evidence. (4 marks) [4] [5]

d) Outline the household and public-health measures that prevent recurrence after treatment. (2 marks) [10]

SAQ 2 — The painful boggy scalp mass and the steroid cream (10 marks, 15 minutes)

A four-year-old girl is brought to the emergency department with a two-day history of a painful, swollen, boggy, purulent mass on the scalp, studded with pustules, with crusting and enlarged cervical nodes. The family acquired a kitten two weeks earlier. In the next cubicle, a parent asks whether to keep using a combined corticosteroid, antifungal and antibiotic cream on an itchy annular forearm rash. [1]

a) What is the scalp diagnosis, and why is the new kitten a relevant clue? (2 marks) [1]

b) Outline the definitive management of this scalp lesion, naming the drug classes and the specific procedure that must be avoided, with the reason. (4 marks) [2]

c) Explain to the parent what will happen if the combined cream is continued on the annular forearm rash, and name the resulting condition. (2 marks) [6]

d) State two sequelae of inadequate treatment of the scalp lesion that you would discuss with the family. (2 marks) [1]