Bullous prurigo pigmentosa.

Prurigo pigmentosa is a rare inflammatory skin disease of unknown etiology, characterized by recurrent, symmetrical, pruritic, erythematous papules resulting in gross reticular hyperpigmentation. The rash occurs mainly on the back, the chest and the nape of the neck. While PP is observed rather frequently in Japan, only a few cases have come to notice in other countries. Vesicular or bullous forms have been reported only rarely. The differential diagnosis includes lichen pigmentosus, pigmented contact dermatitis, confluent and reticulated papillomatosis of Gougerot and Carteaud, dermatitis herpetiformis and bullous lichen ruber planus. This case report concerns a young Caucasian patient with prurigo pigmentosa, in whom predominantly vesicular, but also bullous manifestations appeared on an existing maculopapular eruption on the trunk.