Methods
Laboratory tests such as complete blood count, biochemistry, and urine analysis were within normal ranges. A punch biopsy of the knee lesion was obtained with a differential diagnosis of psoriasis and PRP. The histopathological study revealed a psoriasiform epidermal hyperplasia with alternating hyperorthokeratosis and parakeratosis in horizontal and vertical directions. Additionally, there was hypergranulosis, mild spongiosis, and moderate superficial perivascular infiltration, which were more indicative of pytriasis rubra pilaris (PRP) (Figure 2). Based on clinicopathologic correlation, the patient was diagnosed with type III juvenile PRP. Treatment with topical corticosteroid and tacrolimus 0.1% ointment was initiated. Unfortunately, the disease was progressive and there was no response to topical treatment. After discussing systemic therapy options with the parents, cyclosporine A (CsA) 25 mg daily (2.5 mg per kg) was initiated, with regular monitoring of blood pressure and electrolytes.