Rosacea of common male baldness.

Four patients are described in whom rosacea occurred on the face, and on the scalp in patches of baldness. Histopathological examination of the specimens taken from the scalp showed changes of rosacea and basophilic degeneration of collagen. In two patients direct immunofluorescence studies were performed; in one of these the presence of IgG deposits at the dermo-epidermal junction was demonstrated. These observations confirm the influence of external factors in the pathogenesis of rosacea.