The single most common skin disease in teenagers, acne (acne vulgaris) occurs when the skin pores become clogged with excess sebum (oil), dirt and dead skin cells. Bacterial infection can then lead to further inflammation of the skin and the eruption of red, inflamed pimples. The skin condition is also commonly characterised by whiteheads and blackheads.
As many as 95% of males and 85% of females suffer from some form of acne during adolescence. Although the physical effects of acne are usually only cosmetic, the condition can have a highly detrimental effect on a young person’s psychological well-being.
The surface of the skin contains pores, each of which opens into a canal called a follicle. Each follicle contains a hair and an oil gland (sebaceous gland). The oil (sebum) from these glands lubricates the skin and helps remove dead skin cells. If too much sebum is produced, the pores may become blocked with the accumulation of dirt, debris and bacteria. The blockage is called a plug or a comedone. If these plugs rupture, the oil and bacteria can leak into the surrounding tissue, leading to inflammation. If the inflammation spreads deep into the skin, the pimples may enlarge to form cysts which can become painful.
Acne can be caused (or exacerbated) by:
- Genetic factors (i.e. family history of acne): a strong genetic component is believed to be associated with acne and a family history predisposes individuals to developing the condition. About 81% of the variance in acne can be attributed to genetic factors, whilst only 19% is due to environmental factors.
- Excess production of androgens (the hormones which control male characteristics): this can occur in some obese individuals, individuals with adrenal hyperplasia (enlargement of the adrenal glands, hormone-producing glands which lie above the kidneys) and other endocrine (hormonal) disorders.
- Excessive combing or brushing of hair
- Sweating or a humid environment
- Pore-blocking (comedogenic) cosmetics: such as those containing the ingredient isopropyl myristate
- Hormonal changes: as can occur during pregnancy or with the use of oral contraceptives
- Certain medications: including steroids and phenytoin (anti-epileptic drug)
A cross section of skin with acne
Acne and diet
While there is a significant genetic component underlying acne (approximately 80%), the bulk of scientific evidence indicates there is also some association with diet. Diets high in dairy products, particularly cow’s milk, have been shown to increase the incidence and severity of acne; this is because such products contain hormones. Further studies have demonstrated that eating large amounts of carbohydrates with a high glycemic index (GI) (i.e. sugar, potatoes, white bread and rice) may influence the development, severity and duration of acne. Conversely, diets high in protein and low GI carbohydrates (wholegrain breads and pastas) can improve breakouts.
The following self-care steps may aid in decreasing the severity of acne:
- Washing the skin with a mild, non-drying soap once or twice a day
- Avoiding excessive washing of the skin
- Avoiding comedogenic (pore-blocking) cosmetics, such as those containing the ingredient isopropyl myristate
- Avoiding rubbing, squeezing, scrubbing or picking pimples
Acrylate glue based products, sold at pharmacies, may be used at home to extract the plugs of dead skin and sebum which form in pores (comedones). It should be noted that this is not the same as picking at spots, which can lead to scarring.
Physicians (or beauty therapists) are able to extract comedones manually without scarring the skin. Pursuing this treatment once or twice a month may, in combination with other treatment options, lead to a quicker resolution of acne. For severe cases of acne, chemical skin peels, surgical removal of scars and cysts or photodynamic therapy (see below) may be warranted.
Early stage acne
Early stage acne is characterised by blackheads, whiteheads and the occasional small pimple; it is mild and does not result in redness or inflammation. For early-stage acne, keratolytic agents are the most effective topical treatment. They prevent the blockage of the follicle by softening skin cells which then slough off easily rather than getting trapped and forming a plug. Keratolytic agents include:
- Retinoids: artificial vitamin A derivatives. The most potent of all keratolytic agents, the retinoid tretinoin is considered the gold standard against which new products are compared. It acts by loosening skin cells near the follicles to regulate their shedding and prevent comedones (plugs of sebum and dead skin cells) from forming. Side-effects include skin irritation, photosensitivity (abnormal reactions of skin to light and sunlight) and an initial flare-up of acne. Another retinoid, adapalene, is able to resolve comedones and reduce inflammation; it causes less irritation than tretinoin.
- Azelaic acid: a naturally occurring compound that helps skin cells detach so they do not build up in the follicles. It also has anti-inflammatory and anti-bacterial properties. Itching and burning sensations are occasional adverse effects.
- Alpha- and Beta-hydroxy acids: both substances have limited effectiveness as comedolytics, substances which resolve comedones.
Inflammatory phase acne
As its name suggests, the inflammatory phase of acne includes inflamed breakouts and the development of a number of papules and pustules. It invariably involves overgrowth of bacteria called Propionibacterium acnes. The following treatments may be prescribed for acne at this stage:
- Benzoyl peroxide: a drug which destroys the P acnes bacteria, benzoyl peroxide is available as an over-the-counter preparation. It sterilises the follicle and reduces the number of comedones via these antibacterial effects. Dry skin and allergic reaction are possible side-effects.
- Topical antibiotics: the antibiotics clindamycin and erythromycin reduce numbers of bacteria and have anti-inflammatory action. A mixture of one of these medications with benzoyl peroxide may be more effective than either treatment on its own.
- Oral antibiotics: These agents are used in patients with moderate to severe forms of acne who are at risk of scarring. Tetracyclines, erythromycin and trimethoprim are the antibiotics of choice. Adverse effects, such as impairment of the liver or kidney, may occur, especially with long-term use.
- Anti-androgenic therapies: anti-androgens impede the activities of androgens (male sex hormones) and may prove useful in the treatment of acne. It should be noted, however, that in some instances, the use of one form of anti-androgenic therapy, oral contraceptives, may actually worsen acne.
- Isotretinoin: given orally, isotretinoin is helpful in treating nodulocystic acne, a severely inflamed form of acne which involves the development of large, pus-filled cysts and hard, painful lumps, or nodules, under the skin. Isotretinoin reduces the production of sebum (oil) to pre-pubertal levels and an equivalent decrease in the Propionibacterium acnes bacteria also occurs. Common adverse effects include: dry, scaly, itchy or inflamed skin; dry cracked lips; and dry mouth, throat or vagina. These side-effects usually disappear after stopping the medication. In rare cases, acute fulminans can occur with isotretinoin therapy, this condition is characterised by highly ulcerated acne, fever and painful, swollen joints. Psychological impairment, such as depression and suicidal tendencies, can also occur with isotretinoin; simultaneous use with certain drugs should be avoided. Isotretinoin is contraindicated during pregnancy due to the danger of birth defects.
- Photodynamic therapy: light and laser therapy may be used in combination with other therapies for acne in patients who do not respond to a single treatment option alone, or who experience significant adverse effects with other modes of treatment. Photodynamic therapy works by one of two mechanisms – by killing the Propionibacterium acnes bacteria or by minimizing the sebaceous glands. The Propionibacterium acnes bacteria on the skin naturally produce compounds called ‘porphyrins’. When the skin is exposed to blue light, or other specific wavelengths, it activates these porphyrins inside the bacteria to form oxygen free radicals capable of destroying them. Various lasers and radiofrequency devices are able to minimise or selectively destroy the sebaceous (oil) glands in the skin. These can be helpful in the treatment of acne, as they reduce the amount of sebum produced which reduces clogged pores and comedones.
Acne usually resolves after adolescence. It may, however, recur or appear for the first time in adulthood in some individuals. Untreated acne can lead to the formation of painful cysts, and physical and emotional scarring. Consulting a general practitioner or dermatologist may be warranted, if the acne is severe or if it has not responded to over-the-counter treatments.
Although acne responds well to treatment, it may recur from time to time. The earlier the onset of acne, particularly in females, the more likely it is to recur in adulthood. It is important to note that like all medicines, treatment of acne (especially tretinoin) can cause side effects. Moreover, many of the commonly prescribed agents for acne are teratogenic, meaning that they can affect development and cause malformations in a growing fetus or embryo, thus their use should be avoided during pregnancy.
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