(ăk′nē)
[Pronunciation]
[Gr. akme, point]

1. An inflammatory disease of the sebaceous follicles of the skin, marked by comedones, papules, and pustules.
It is exceptionally common in puberty and adolescence. Acne usually affects the face, chest, back, and shoulders. In severe cases, cysts, nodules, and scarring occur.

ETIOLOGY
The cause is unknown, but predisposing factors include hereditary tendencies and disturbances in the androgen-estrogen balance. Acne begins at puberty when the increased secretion of androgen in both males and females increases the size and activity of the pilosebaceous glands. Specific inciting factors may include food allergies, endocrine disorders, therapy with adrenal corticosteroid hormones, and psychogenic factors. Vitamin deficiencies, ingestion of halogens, and contact with chemicals such as tar and chlorinated hydrocarbons may be specific causative factors. The fact that bacteria are important once the disease is present is indicated by the successful results following antibiotic therapy. The lesions may become worse in women and girls before the menstrual period.

SYMPTOMS
Acne vulgaris is marked by either papules, comedones with black centers (pustules), or hypertrophied nodules caused by overgrowth of connective tissue. In the indurative type, the lesions are deep-seated and cause scarring. The face, neck, and shoulders are common sites. Acne may be obstinate and recurrent.

TREATMENT
Treatments include skin cleansing, topical agents (e.g., azelaic acid or benzoyl peroxide or vitamin A derivatives), and oral or topical antibacterial drugs.

PATIENT CARE
The patient is instructed to wash the skin thoroughly but gently, avoiding intense scrubbing and skin abrasion; to keep hands away from the face and other sites of lesions; to limit the use of cosmetics; and to observe for, recognize, and avoid or modify predisposing factors that may cause exacerbations. The need to reduce sun exposure is explained, and the patient is advised to use a sunscreen agent when vitamin A acid or tetracycline is prescribed. Information is provided to fill knowledge gaps or correct misconceptions, and emotional support and understanding are offered, particularly if the patient is an adolescent. Patients (and others) need to be aware that extensive use of antibiotic treatment for acne increases the prevalence of antibiotic-resistant facial bacteria and can affect treatment response. Most improvement occurs during the first 6 weeks of therapy, whatever the regimen. More than half of all patients respond to therapy. Colonization with tetracycline-resistant propionibacteria diminishes response to all oral antibiotic regimens. Skin irritation as an adverse effect to treatment occurs most commonly with topical benzoyl peroxide alone, which is the most cost-effective treatment. Adding topical erythromycin may help reduce irritation and increase efficacy.

Because of the teratogenicity of some acne medications (such as isotretinoin), pregnancy must be avoided during their use.

2. Acne vulgaris.

Subentries:
acne atrophica
bromide acne
acne ciliaris
acne conglobata
cystic acne
acne fulminans
halogen acne
acne indurata
keloid acne
acne keratosa
acne neonatorum
acne papulosa
petroleum acne
acne pustulosa
acne rosacea
steroid acne
summer acne
tropical acne
acne urticaria
acne varioliformis
acne vulgaris