Acne Conglobata of the Scalp.

Acne conglobata (AC) is a rare form of severe and chronic nodulocystic acne. It is characterized by nodulocystic lesions, borrowing, interconnecting abscesses, scars, in addition to grouped comedones. AC usually appears on the trunk and may extend to the buttocks. It can also appear, to a lesser extent, on the face, neck, shoulders, proximal arms, abdomen, and thighs. To the best of our knowledge, AC of the scalp has not been reported in the literature. Herein, we are reporting a case of AC of the scalp, emphasizing its clinical and trichoscopic features and how to differentiate it clinically from similar scalp conditions, especially alopecic and aseptic nodules of the scalp and dissecting cellulitis of the scalp.