Acne is an inflammatory disease of the skin caused by changes in the pilosebaceous units (skin structures consisting of a hair follicle and its associated sebaceous gland). The most common form of acne is known as “acne vulgaris”, which means common acne. Excessive secretion of oils from the glands combine with naturally occurring dead skin cells to block the hair follicles. Oil secretions build up beneath the blocked pore, providing a perfect environment for the skin bacteria Propionibacterium acnes (P. acnes) to multiply uncontrolled. In response, the skin inflames, producing the visible lesion. The face, chest, back, shoulders and upper arms are especially affected.
The typical acne lesions are comedones, papules, pustules and cysts. More inflamed rashes take the form of pus-filled or reddish bumps, even boil-like tender swellings. After resolution of the lesions, prominent unsightly scars may remain.
Acne affects a large percentage of humans at some stage in life and usually appears during adolescence, when people already tend to be most socially insecure. The condition is common in puberty as a result of an abnormal response to normal levels of the male hormone testosterone. The response for most people diminishes over time and acne tends to disappear, or at least decrease, after thirty. There is, however, no way to predict how long it will take for it to disappear entirely, and some individuals will continue to suffer from acne decades later, into their thirties and forties and even beyond. Aside from scarring, its main effects are psychological, such as reduced self-esteem and depression.
It is unknown as to why some people get acne and others do not. It is known to be partly hereditary. Several factors are known to be linked to acne:
- Hormonal activity;
- Hyperactive sebaceous glands;
- Accumulation of dead skin cells;
- Bacteria in the pores;
- Skin irritation or scratching of any sort;
- Anabolic steroids;
- Any medications containing halogens (iodides, chlorides, bromides), lithium, barbiturates, or androgens;
- Exposure to high levels of chlorine compounds, particularly chlorinated dioxins, can cause severe, long lasting acne, known as chloracne.
Types of Acne
Acne Vulgaris is the most common type of acne, which affects 85-100% of people at some time in their life. It is characterized by non-inflammatory follicular papules or comedones and by inflammatory papules, pustules, and nodules in its more severe forms. Acne vulgaris affects the areas of skin with the densest population of sebaceous follicles. These areas include the face, the upper part of the chest, and the back.
Acne Conglobata (AC) is an uncommon and unusually severe form of acne characterized by burrowing and interconnecting abscesses and irregular scars (both keloidal and atrophic), often producing pronounced disfigurement. The comedones often occur in a group of two or three and cysts contain foul-smelling seropurulent material that returns after drainage. The nodules often fuse forming unusual shapes of several centimeters. The formation of nodules begins in early puberty and the severity increases until late adolescence or beyond. Active nodule formation may persist for years and usually continues until the fourth decade of life. Isolation of coagulase-positive staphylococci is common in the lesions. As the nodules break down, crusts may form over a deep ulcer, which extends centrifugally, but tends to heal centrally. This process is persistent and slow healing is characteristic. A conspicuous feature of the disease is the blackheads that appear in pairs or groups on the neck and trunk, and sometimes involve the upper arms or the buttocks.
Acne Fulminans (AF), also known as acne maligna, was originally described as acute febrile ulcerative acne conglobata (AC). In 1958, at a meeting of the Detroit Dermatological Society, Burns and Colville presented a 16-year-old boy with acute febrile disease and AC. Many similar cases have been reported since then. The primary features of this disease include sudden onset, severe and often ulcerating acne, fever, polyarthritis, and failure to respond to antibacterial therapy; the response to debridement in combination with steroid therapy is good. It can be the dermatologic manifestation of the synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome.
Acneiform eruptions may consist of comedones, papulopustules, cysts, or nodules that resemble acne vulgaris. Occasionally, this may lead to their initial misdiagnoses. Acne like disorders occur from a wide variety of diseases, including infections, growth anomalies, and drug reactions. Those entities included in this discussion are nevus comedonicus, eruptive hair cysts, tuberous sclerosis, amineptine acne, steroid acne, chloracne, acneiform drug eruptions, gram-negative folliculitis, eosinophilic pustular folliculitis, pityrosporum folliculitis, coccidioidomycosis, secondary syphilis, sporotrichosis, rosacea, and perioral dermatitis.
Eosinophilic Pustular Folliculitis (EPF) is another disease of unknown etiology that usually manifests as a recurrent pruritic papulopustular eruption on the face, trunk, and extremities. Histopathology reveals a predominantly perifollicular infiltration of eosinophils with some mononuclear cells and subcorneal pustules composed of eosinophils. EPF has been described in infants and in immunocompromised patients with HIV, and the classic immunocompetent type is known as Ofuji disease (first described by Ofuji in the adult Japanese population). Patients may also demonstrate blood eosinophilia and leukocytosis. Treatment modalities and results vary greatly. Options include topical and systemic corticosteroids, oral antibiotics, indomethacin, dapsone, isotretinoin, and pulsed ultraviolet phototherapy (PUVA).