Exacerbation of porokeratosis during etretinate therapy.

Four patients with disseminated superficial porokeratosis (DSP) were treated with the oral aromatic retinoid etretinate. Using the standard dosage of 1 mg/kg/day, 3 patients showed exacerbation of cutaneous lesions 4-6 weeks after initiation of treatment. Because of additional severe generalized itching and discomfort in all patients, treatment had to be discontinued. The clinical exacerbation correlated with a significant increase in the lymphohistiocytic dermal infiltrate beneath the cornoid lamella. In our experience the use of etretinate triggered the exacerbation of porokeratotic lesions with associated side effects showing that their use is not necessarily of benefit as previously reported.