Erythematous papules evolving into reticulated hyperpigmentation on the trunk: A case of prurigo pigmentosa

Abstract

Prurigo pigmentosa is a rare cutaneous disorder consisting of a network of erythematous, pruritic papules evolving into reticulated hyperpigmentation with a specific predilection for the trunk. It was first described in Japan in 1971, where the condition still predominates. Although recognition is increasing outside of Japan, the disease is still not well known in the West. Herein, we present the case of a 19-year-old white woman with prurigo pigmentosa diagnosed based on the correlation of clinical and histopathologic findings. Although prurigo pigmentosa is well known in Japan, the low incidence of this disease entity in the United States is likely secondary to underdiagnosis. Thus, the purpose of this case is to increase recognition of this unusual pruritic, reticulated rash.