Prurigo Pigmentosa: Literature Review.

Prurigo pigmentosa, also referred to as Nagashima's disease, is a rare inflammatory skin condition of unknown etiology. It typically presents as pruritic erythematous papules, papulovesicles, and vesicles appearing in a reticular pattern on the back, chest, or neck. The histological features of prurigo pigmentosa vary according to the stage of the disease. Early-stage disease is characterized by a superficial perivascular infiltrate of neutrophils; spongiosis and necrotic keratinocytes commonly appear in later stages. The etiology of prurigo pigmentosa has yet to be determined. Oral minocycline is usually the first-line therapy for prurigo pigmentosa. However, doxycycline, macrolide antibiotics, and/or dapsone (diaminodiphenyl sulfone) may be indicated for some patients. We describe the key features of prurigo pigmentosa, including the epidemiology, clinical and histologic presentation, differential diagnosis, postulated pathogenesis, and treatment options for this condition.