Acne is an almost universal finding in teenagers across the globe. Acne vulgaris is the most common form of acne; it affects almost every human at some point in their lifetime. Most cases are mild and do not cause any significant disease. Most acne vulgaris is seen in the postpubertal years. Many clinical variants exist, and excellent therapeutic modalities are available to treat this skin disease.
Clinical Findings: Acne vulgaris typically begins soon after puberty. It has no racial or gender preference, although males may develop more severe cases of the disease. The first signs of acne development are the formation of microcomedones, both open and closed. Open comedones, also known as blackheads, appear as small (0.5-1 mm), dilated skin pores that are filled with a dark material, oxidized keratin. This material can be easily expressed with lateral pressure or with the help of a comedone extractor. The closed comedone, also known as a whitehead, is a small (0.5-1 mm), whitish to skin-colored papule. Comedones are believed to be the precursor lesion to the other lesions of acne. As acne progresses, inflammatory red, slightly tender papules develop, along with a variable amount of pustules. The pustules are centered on the hair follicle. More severe cases of acne, such as nodulocystic acne, show inflammatory nodule formation as well as cyst formation. These nodules and cysts can become large (2-3 cm in diameter) and can cause considerable pain. They often heal with scarring of the skin.
The face, back, upper chest, and shoulders are the predominant areas of involvement, most likely because of the higher density of sebaceous glands in these regions and the role of the sebaceous gland in the development of acne. Acne is a relentless condition: As one lesion heals, another develops simultaneously. Females often report a flare of their acne 1 week before menstruation begins, denoting hormonal influence. Acne has many clinical variants.
Adult female acne is typically seen in women between 25 and 45 years of age. They often report that they had minimal to no acne during adolescence. This form of acne is found predominantly on the cheeks, perioral region, and jaw line, and it manifests as deep-seated papules, nodules, and cysts. There is a pronounced flare around the time of menstruation.
Neonatal and infantile acne are self-limited types that are seen frequently in this population. Neonatal acne may be seen a day or two after delivery; it is caused by transplacental passage of maternal hormones. It resolves without therapy and seems to be more prevalent in male newborns. Infantile acne is seen after the first few months of life. Most cases show a few transient papules, comedones, and pustules. Most self-resolve, although a few cases last into adolescence.
Acne cosmetica and acne medicamentosa are two similar forms of acne thought to be caused by or exacerbated by the use of cosmetics and facial medications. The removal of these products usually is enough for the patient to see significant improvement. Most products implicated in this form of acne are oily in nature; they cause follicular plugging, which allows acne production.
Acne excoriée is a form of acne that is made worse by chronic picking or manipulation of the acneiform lesions. This often leads to scarring and a worsening of the clinical appearance. It is often coexistent with an underlying anxiety disorder, obsessive compulsive disorder, or depression.
Rare forms of acne include acne fulminans, acne conglobata, and acne aestivalis. Acne fulminans is seen almost exclusively in teenage boys. It is a form of severe cystic nodular acne that heals with severe, disfig- uring scarring. The cysts and nodules can easily rupture and break down, leaving multiple ulcerations. This is associated with systemic symptoms including fever, arthralgias and arthritis, and myalgias. A peripheral leukocytosis is often seen on laboratory examination. Lytic bone lesions can be seen, with the clavicle the most commonly affected bone. This may be preceded by localized pain over the bony involvement. Acne conglobata is a term used to refer to severe cystic acne, which is seen mostly in young males. Patients often have multiple cysts that can be interconnected with sinus tracts. The areas involved are very painful and heal with severe scarring. This form of acne occurs in the same locations as acne vulgaris. Acne conglobata has been seen in association with hidradenitis suppurativa, and some consider these conditions to be in the same spectrum of disease processes. Acne conglobata may run a chronic course well into adulthood, with persistent nodules and cysts coming and going. Acne aestivalis is one of the rarest forms of acne. It has a seasonal variation to its course. It begins in spring and resolves by early fall. It is a disease predominantly of adult women.
Steroid-induced acne occur secondary to the chronic use of oral or intravenous steroids. It manifests as a monomorphic eruption of inflammatory papules. Many other medications can be associated with acneiform eruptions, including iodides, lithium, and the epidermal growth factor inhibitors.
Pathogenesis: Acne is believed to have a multifactorial basis. Follicular keratinization appears to be faulty, and the keratinocyte adhesions do not separate as quickly as they should, leading to a follicular plug and microcomedone formation. Excessive sebaceous gland production also plays a role and is probably mediated by hormonal influences. If the sebaceous gland material is produced in an amount sufficient to cause rupture of the comedone, the contents spill into the dermis, causing an inflammatory response; clinically, this is manifested by inflammatory papules, nodules, and cysts. The third player in the pathogenesis is the gramnegative anaerobic bacteria, Propionibacterium acnes. This bacteria is believed to cause an activation of the immune system and results in an inflammatory infiltrate. Rare causes of acne include adrenal gland disorders that can cause virilization. These tumors are rare and often are associated with a sudden onset of acne, hirsutism, and irregular menstrual cycles. Any state of hyperandrogenism can cause acne or make preexisting acne worse. The most common cause is the polycystic ovarian syndrome in women. Less commonly, a Sertoli-Leydig cell tumor can lead to a hyperandrogenic state and resultant acne.
Histology: Biopsies of acne are not required for diagnosis. A biopsy specimen from an inflammatory acne papule shows a folliculocentric lesion with a dense inflammatory infiltrate. The follicular epithelium has signs of spongiosis. Foreign body giant cells, plasma cells, neutrophils, and lymphocytes are all seen in varying degrees. Comedones show compacted corneocytes within the sebaceous gland lumen.
Treatment: Treatment for acne vulgaris is multidimensional. One often uses a combination of a keratolytic and antibacterial agent, such as benzyl peroxide, with tretinoin (a medication that increases differentiation and maturation of keratinocytes) and an antibiotic. The antibiotics are used for their antiinflammatory and antibacterial properties. The antibiotic may be given in a topical or oral form. More severe acne, cystic acne, acne conglobata, and acne fulminans require the systemic use of isotretinoin to prevent severe scarring. Isotretinoin is given for 5 to 6 months. Significant precautions need to be taken, because this medication is a well-known teratogen. Prednisone is often advocated for these severe cases of cystic acne. It is usually used transiently, when first beginning therapy with isotretinoin, to help decrease some of the severe inflammation. It should not be used for long periods.
Many other treatment options exist, including topical agents such as azelaic acid, adapalene, tazarotene, salicylic acid, and topical antibiotics. Oral medications that can be used include multiple oral antibiotics, spironolactone, and birth control pills. The latter two medications are especially helpful in the treatment of adult female acne. They work on the hormonal influence on acne and are highly successful in this type of patient.
All the medications used for acne have potential side effects, and treatment must be tailored to the individual. Comedone extraction, intralesional triamcinolone, and photodynamic therapy have shown some success in treating acne. Laser resurfacing, chemical peels, and use of artificial fillers should be reserved for the treatment of scarring after the inflammatory acne has been controlled.