chapter  24
4 Pages

Phototherapy of Acne Vulgaris

Acne vulgaris is a disease of sebaceous glands characterized by comedones, papules, pustules, and cystic lesions and has a complex pathophysiology including

Hyperkeratinization of the neck of the hair follicle and of the sebaceous duct resulting in obstruction

Increased production of sebum Increased free fatty acid content of sebum due to bacterial activity,

predominantly by propionibacterium acnes Often rupture of the follicle and release of sebum and keratin into

the dermis Inflammation An influence by hormonal and climatic factors and emotional

stress. Interest in using photons to interrupt or prevent this cascade of events

is usually attributed to the observation that acne often improves during summer and a belief, by physicians and patients, that sunlight helps to clear acne; there are no studies to support this belief. Sunlight is a very complex environment involving exposure to multiple wavebands of radiation, often in a relaxed or hormone-stimulating setting and it can induce tanning, which will camouflage acne lesions. A further complication is that about 20% of patients with acne are made worse by exposure to sunlight.