Painful papule of the ear: a follicular disorder.

The etiology of painful papule of the external ear, chondrodermatitis nodularis chronica helicis, has been an enigma for over half a century. I reviewed 84 skin biopsy specimens from 82 patients with this histopathologic diagnosis and found evidence that the infundibular portion of the hair follicle is probably the primary cutaneous structure involved in this condition. This lesion appears to evolve from an acute, suppurative, granulomatous dermatitis into a later-fibrosing dermatitis having the clinical and histologic features of perforating folliculitis and prurigo nodularis.