Eosinophilic pustular folliculitis.

Classical eosinophilic pustular folliculitis, or Ofuji's disease, is a chronic and relapsing dermatosis that is predominantly reported in East Asian populations. Clinically, the disease typically begins as small papules, which enlarge and coalesce into a large plaque, usually on the face. The histopathology is characterized by a prominent eosinophilic infiltrate in the dermis with concentration around pilosebaceous units, often with eosinophilic microabscess formation. The differentiation of eosinophilic pustular folliculitis from other eosinophilic dermatoses is practically challenging and requires close clinicopathologic correlation. Eosinophilic pustular folliculitis may also be associated with human immunodeficiency virus infection, various drugs, and some lymphomas and could also be thought of as a nonspecific dermatopathologic pattern in such settings. The cause of classical eosinophilic pustular folliculitis is unknown, although immune processes are almost certain to play a key role in its pathogenesis.