Follicular Occlusion Syndrome

The document discusses a group of four related diseases: Hidradenitis suppurativa, dissecting cellulitis of the scalp, acne conglobata, and pilonidal sinus, which are collectively known as follicular occlusion syndrome. These conditions share similar clinical features and underlying mechanisms, primarily involving the thickening of the stratum corneum and keratin plugging at the hair follicle ductal isthmus. When a patient presents with three of these conditions, it is referred to as the follicular occlusion triad, and when all four conditions are present, it is known as the follicular occlusion tetrad. The document includes a photogallery to illustrate these diseases.