Transcript Pathogenesis of Acne

Pathogenesis of Acne
• Follicular disease, comedo formation
• Produced by the impaction and distension
of the follicles with a
keratinous plug in the
lower infudibulum
• Hyperproliferation and abnormal differentiation of
keratinocytes
• increased sebum secretion
• Lower portion of follicle is dilated by
retianed/entrapped sebum and keratinous
materials
• Disruption of follicular epithelium permits discharge of follicular
contents into the dermis
• Bacteria, keratin and sebum leads to release of proinflammatory
mediators and accumulation of T helper cells, neutrophils and
giant cells
• Formation of inflammatory papules, pustules
• Marked inflammation causes nodulocystic
lesions
• Comedogenic, greasy, occlusive products
– Ex. Pomade or gel used on the hair
• Mechanical and frictional forces
– Ex. Tight strap on a sports helmet
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Repeated laser hair removal
Genetic factors
Hyperandrogenic states (PCOS), menstruation
Prolonged use of topical or oral steroids
Other skin irritants or chemical/industrial
compounds
• Comedones
– Thinned epithelium and a dilated follicular canal
filled withlamellar lipid-impregnated keratinous
materials
• Pustular
– Folliculocentric abscess surrounded by dense
inflammatory exudate of lymphocytes and PMNs
• Nodular
– Indolent, contain plasma cells, foreign body giant
cells, proliferation of fibroblast