A 38-year-old female patient suddenly developed an unusual tuberous, pustular tumor on her chin. On the basis of clinical pattern, histological and microbiological investigations the diagnosis of demodicosis was established. Histological investigation revealed follicular cysts and a chronic granulomatous perifolliculitis with many of Demodex folliculorum. A large number of mites could be also identified by microscopy of smears from pustules. No cellular or humoral immunological defects, tumours nor systemic disorders were found. After oral therapy with steroids and metronidazole, the lesions improved rapidly.