Purple, polygonal pruritic papules with Wickham striae describe which condition?

• A. Lichen planus
• B. Psoriasis
• C. Tinea versicolor
• D. Pityriasis rosea

Answer: (A)

This presentation is classic for lichen planus. The violaceous or purple color, the pruritic, polygonal papules, and the fine white Wickham striae seen on the surface together point strongly to this condition. Wickham striae are caused by changes in the epidermis (hypergranulosis) that create a lace-like network on the lesion, which is a characteristic hallmark of lichen planus.

Other conditions don’t fit this exact mix of features. Psoriasis tends to produce well-defined plaques with silvery scales rather than violaceous, shiny papules with Wickham lines. Tinea versicolor presents as patchy hypopigmented or hyperpigmented areas with subtle scale and is caused by a fungal infection, not a lace-like surface change. Pityriasis rosea starts with a herald patch and then a Christmas-tree pattern of oval lesions with peripheral scaling, again without Wickham striae.

So the combination of purple, polygonal, pruritic papules and Wickham striae specifically points to lichen planus.