Psoriasis on the Knees

A 28 year-old man sought medical attention for a minimally pruritic “rash” on both knees.

Key point: The patient’s eruption consisted of well-demarcated erythematous plaques covered by silvery scale. Both morphology and location favor the diagnosis of psoriasis. The presence of nail pitting, and a strongly positive family history for psoriasis, confirmed the diagnosis.

Treatment: Due to the localized nature of the psoriasis, the affected areas were treated with excimer laser. Resolution occurred and a long remission ensued.

Note: Laser therapy, along with application of a topical steroid, retinoid, or tar might all be appropriate for this patient. Duration of remission is longest following some form of light therapy.