Suspected Psoriasis vs Eczema in Adult Patient

Clinical History

‍28-year-old male with well-demarcated erythematous plaques with silvery scale on both elbows and knees for four months. Small patch behind left ear. No prior skin disease. Father has psoriasis. Using OTC hydrocortisone 1% without improvement.

Clinical Question

‍This looks like psoriasis to me given the distribution and family history. Does he need a biopsy, and can I start treatment here?

Specialist Guidance

‍Classic plaque psoriasis. Well-demarcated plaques, silvery scale, extensor surfaces, retroauricular involvement, positive family history. No biopsy needed. The hydrocortisone 1% won’t touch this. Low-potency OTC steroids aren’t effective for psoriasis plaques at elbows and knees. Start betamethasone dipropionate 0.05% ointment twice daily for 2–4 weeks, then weekends only for maintenance. Use a medium-potency steroid behind the ear, such as triamcinolone 0.1% cream, to avoid skin thinning.

At follow-up, consider transitioning to calcipotriene as a steroid-sparing maintenance option. Refer to derm if plaques don’t respond after 6–8 weeks or disease extends beyond 5% BSA. At that point he would likely need systemic therapy, potentially including biologics. Screen for joint symptoms at every follow-up.

Psoriatic arthritis can develop at any point, and early identification improves outcomes.

Outcome

‍Started betamethasone ointment. Plaques cleared substantially within four weeks. Weekend maintenance. No joint symptoms. Managed entirely in primary care. No referral required.