Demodex Folliculitis of the Scalp: Clinicopathological Study of an Uncommon Entity

In a study of 333 scalp biopsies from patients with hair loss and alopecia, Demodex mites were detected in 17 cases (5.1%), but only 4 cases (1.2%) showed clinical and histopathological evidence of Demodex folliculitis, characterized by hair loss, scalp erythema, scales, and pustules. These 4 cases also presented with neutrophilic and/or mononuclear-cell folliculitis with occasional granulomas in histopathological examination. The affected patients responded completely to treatment with metronidazole. The study concluded that Demodex mites are infrequently pathogenic in scalp biopsies for hair loss and alopecia, but when they are, the condition resembles rosacea-like demodicosis and can be effectively treated with anti-Demodex therapy.