Hidradenitis suppurativa and follicular occlusion syndrome: Where is the pathogenetic link?

The follicular occlusion tetrad complex encompasses several entities (hidradenitis suppurativa, acne conglobata, dissecting cellulitis of the scalp, and pilonidal cyst) that share common clinical features, risk factors, and pathophysiology. Follicular occlusion is a crucial triggering mechanism in the etiology in each of these disorders, leading to development of distinctive skin lesions such as deep-seated nodules, abscesses, comedones, and draining sinuses, often with accompanying scarring. Despite the fact that the follicular occlusion tetrad components manifest multiple similarities, they also exhibit many differences among themselves and require individual approaches and treatment.