Follicular occlusion tetrad is a condition including hidradenit is suppurativa, acne conglobata, dissecting cellulitis of scalp and pilonidal sinus. The exact pathogenesis of this group of disease is unknown but evidence suggests that they share the same pathological process ini t iated by fol l icular occlusion. Hidradenitis suppurativa (HS) is an uncommon disease affecting the axillae and ano...