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Chapter 2. Acne Vulgaris

Integration: Unifying Concept

Every textbook of dermatology and dermatopathology asserts that acne vulgaris is a disease of the hair follicle. That contention is dead wrong; the follicle (bulb, stem, and isthmus) is unaffected. It is infundibular epidermis. i.e., the infundibulum, that is essential to the process.

The infundibulum-centered acne vulgaris and variants of it seem to be a single pathologic process. The spectrum of its severity ranges from comedones and inflamed papules that resolve without residua to fluctuant and draining sinuses that heal with ugly scars. But whether the condition is called acne vulgaris, acne conglobata, acne keloidalis, hidradenitis suppurativa, or dissecting cellulitis of the scalp (perifolliculitis capitis abscedens et suffodiens), the process is fundamentally the same.

Inflammatory cells, neutrophils chief among them, appear first around and then within infundibula. If the collection of neutrophils is confined to an infundibulum, the lesion is a pustule. If the process is more florid and the collection of neutrophils is so great that much of an infundibulofollicular unit is obscured by it, pseudocarcinomatous proliferation of infundibular keratocytes develops in an attempt to contain it. The result is one or more of a constellation of acne conglobata, acne keloidalis, dissecting cellulitis of the scalp, and hidradenitis suppurativa. The legitimacy of the concept that acne is basically a single pathologic process seems to be verified by the fact that all of its manifestation—among them, vulgaris, conglobata, keloidalis, dissecting cellulitis, and hidradenitis suppurativa—may be present in one person. For acne, in any of its expressions, to come into being requires the play of androgens on the infundibulosebaceous unit.