Eosinophilic pustular folliculitis (Ofuji's disease). Immunohistochemical analysis

Eosinophilic pustular folliculitis is a distinctive dermatosis that was first described in Japan. Although the histopathologic feature of eosinophilic pustular folliculitis is characterized by follicular infiltrates with numerous eosinophils, its pathophysiology remains unclear. The lesional skin of five patients with eosinophilic pustular folliculitis was examined using several monoclonal antibodies including a variety of anti-leukocyte adhesion molecules: endothelial cell adhesion molecule 1, vascular cell adhesion molecule 1, and intercellular adhesion molecule 1, by means of immunohistochemical techniques.

Intercellular adhesion molecule 1 expression by keratinocytes was observed on follicular epithelium, but not on epidermis. The migration of eosinophils and lymphocytes, which were intensely positive for antilymphocyte function-associated antigen 1, was limited to follicular epithelium. Endothelial cell adhesion molecule 1 and vascular cell adhesion molecule 1 expression of vascular endothelium was more often observed around hair follicles. There was no reactivity for interleukin 8 in follicular epithelium.

These findings may explain the selective migration of eosinophils and lymphocytes to the hair follicles in eosinophilic pustular folliculitis.