Explaining chronic plaque psoriasis and topical therapy — OSCE

Candidate instructions (8-minute station)

You are the paediatric registrar in the clinic. An 11-year-old girl has a one-year history of thick, well-demarcated, scaly patches on the elbows, knees and scalp, with nail pitting. Her father has psoriasis, she is overweight, and she has become reluctant to wear short sleeves at school. The family asks whether the condition is contagious, whether the creams are safe, and whether it will go away. [1]

Your tasks are: [1]

1. Explain the diagnosis of psoriasis in plain, reassuring language, including that it is not contagious and that it is a chronic immune-mediated condition that often runs in families. [2]
2. Explain the topical treatment — a potency-matched corticosteroid plus calcipotriol — and the safety rules, including why a milder cream is used on the face and flexures. [1]
3. Explain the comorbidities to watch for — weight, joints and mood — and why controlling the weight matters. [11]
4. Set the expectation for the long term, including when stronger treatments such as phototherapy or a biologic might be considered. [1]

You are not expected to start a systemic or biologic agent in this station — that decision is made with a dermatologist. [9]

Examiner prompt to the actor (parent)

"So it is psoriasis, like her dad. Is it catching — can her little brother get it from her? And I have heard steroid creams thin the skin, so are they really safe for a child? Will it ever go away, or is she stuck with this forever? She is already refusing to wear short sleeves because the children stare." [2]

Marking domains

• Frame and explanation (3): explains psoriasis as a common, non-contagious, immune-mediated skin condition that runs in families and comes and goes over a lifetime, in plain, reassuring language; names that it is not an infection and cannot be caught by her brother; acknowledges the visible, chronic nature and the distress of being stared at. [2]
• Treatment and safety (3): explains the topical treatment clearly — a corticosteroid cream combined with a vitamin-D cream such as calcipotriol for the body, with a milder steroid such as hydrocortisone on the face and skin folds to avoid thinning the skin; explains that used correctly and in short courses the creams are safe, and that regular moisturisers form the foundation. [1]
• Comorbidities (2): explains that psoriasis in children is linked to being overweight, to joint inflammation and to effects on mood, and that is why the team will check her weight and blood pressure, ask about stiff or swollen joints, and ask about how she is coping at school; explains that healthy weight management helps the skin as well as her general health. [11]
• Long-term plan (2): sets the expectation of a chronic, relapsing condition managed in partnership over years, with topical therapy now and escalation to light treatment (narrowband UVB) or stronger medicines such as methotrexate or a biologic injection only if the disease or its impact becomes severe, in collaboration with a dermatologist. [1]

Model answer — the explanatory script

"Thank you for bringing her in. What she has is psoriasis, the same condition her dad has, and the good news is we understand it well and we have good treatments. It is an immune condition of the skin — her skin cells are turning over a bit too fast, which is what makes those thick, scaly patches. It is not an infection, it is not contagious, and her brother cannot catch it from her. It does tend to run in families, which is why her dad has it too, but it is nobody's fault and she did nothing to cause it." [2]

"Let me answer your questions one at a time — the treatment, the safety, the comorbidities, and the long term." [1]

"First, the treatment. The foundation is a good moisturiser, used generously and often — that softens the scale and keeps the skin comfortable. On top of that, I am going to give her two creams to use on the patches. One is a steroid cream, and the other is a vitamin-D cream called calcipotriol, which works in a different way and lets us use less steroid. For the patches on her elbows and knees I will use a stronger steroid for a short course to get them under control, and then step down. For her face, if she gets any patches there, I will use a much milder steroid, hydrocortisone, because strong steroids can thin the delicate skin of the face and the skin folds. Used the way I describe — short courses on the body, mild on the face — the creams are safe and do not thin the skin." [1]

"Second, the things psoriasis is linked to beyond the skin. Children with psoriasis are a bit more likely to be carrying extra weight, and the weight is linked to the psoriasis — it can make the skin disease worse and it carries some long-term health risks. So we will check her weight and height and her blood pressure today, and we will talk about healthy eating and activity as part of looking after the whole child, not just the skin. I will also ask about her joints — any stiffness in the morning or swelling — because psoriasis can affect the joints in some children, and we want to pick that up early. And I want to ask how she is coping, because having a visible skin condition at her age is hard, and it can affect mood and confidence. Her reluctance to wear short sleeves tells me it is bothering her, and that matters as much as the skin itself." [11]

"Third, the long term. Psoriasis is a chronic condition — it tends to come and go over a lifetime, so I want to be honest with you about that. There is no cure that switches it off forever, but there is a lot we can do to control it. For now, the creams are the right place to start. If they are not enough, the next step is a light treatment called narrowband UVB, which she would have in the dermatology clinic a couple of times a week. And if we ever need more than that, there are stronger medicines — tablets such as methotrexate, and injectable treatments called biologics that have transformed severe psoriasis in children. We would only go there with a dermatologist, and only if the skin or the impact on her life became severe. The relationship we build now is the one that carries her through, so let's start with a plan she and you are comfortable with, and review her together." [1] [9]