acne n : an inflammatory disease involving the sebaceous glands of the skin; characterized by papules or pustules or comedones

English

Etymology

New Latin, probably a corruption of ακμή, acme

Pronunciation

• /ˈæk.ni/, /"

Primary causes

Exactly why some people get acne and some do not is not fully known. It is known to be partly hereditary. Several factors are known to be linked to acne:

• Family/Genetic history. The tendency to develop acne runs in families. For example, school-age boys with acne often have other members in their family with acne as well. A family history of acne is associated with an earlier occurrence of acne and an increased number of retentional acne lesions.
• Hormonal activity, such as menstrual cycles and puberty. During puberty, an increase in male sex hormones called androgens cause the glands to get larger and make more sebum.
• Stress, through increased output of hormones from the adrenal (stress) glands, although modern tests have said otherwise and point to this not being a cause.
• Hyperactive sebaceous glands, secondary to the three hormone sources above.
• Accumulation of dead skin cells.
• Bacteria in the pores. Propionibacterium acnes (P. acnes) is the anaerobic bacterium that causes acne. In-vitro resistance of P. acnes to commonly used antibiotics has been increasing.
• Skin irritation or scratching of any sort will activate inflammation.
• Use of anabolic steroids.
• Any medication containing halogens (iodides, chlorides, bromides), lithium, barbiturates, or androgens.
• Exposure to certain chemical compounds. Chloracne is particularly linked to toxic exposure to dioxins, namely Chlorinated dioxins.

Diet

Milk

A recent study, based on a survey of 47,335 women, did find a positive epidemiological association between acne and consumption of partially skimmed milk, instant breakfast drink, sherbet, cottage cheese, and cream cheese. The researchers hypothesize that the association may be caused by hormones (such as several sex hormones and bovine IGF-I) present in cow milk. Though there is evidence of an association between milk and acne, the exact cause is unclear. Most dermatologists are awaiting confirmatory research linking diet and acne but some support the idea that acne sufferers should experiment with their diets, and refrain from consuming such fare if they find such food affects the severity of their acne.

High carbohydrates/High GI

It has also been suggested that there is a link between diets high in refined sugars and processed foods and acne. The hypothesis is that rapidly digested carbohydrate foods, such as white bread and refined sugars, produces an overload in metabolic glucose that is rapidly converted into the types of fat that can build up in sebaceous glands. According to this hypothesis, the startling absence of acne in non-westernized societies could be explained by the low glycemic index of these cultures' diets. Others have cited possible genetic reasons for there being no acne in these populations, but similar populations shifting to these diets do develop acne. Note also that the populations studied consumed no milk or other dairy products. Further research is necessary to establish whether a reduced consumption of high-glycemic foods (such as soft drinks, sweets, white bread) can significantly alleviate acne, though consumption of high-glycemic foods should in any case be kept to a minimum, for general health reasons. Avoidance of 'junk food' with its high fat and sugar content is also recommended. The University of Pennsylvania and the US Naval Academy conducted experiments that fed subjects chocolate or a bar with similar amounts of macronutrients (fat, sugar etc.) and found that consumption of chocolate, frequent or not, had no effect on the developing of acne.

Vitamins A and E

Studies have shown that newly diagnosed acne patients tend to have lower levels of vitamin A circulating in their bloodstream than those that are acne free. In addition people with severe acne also tend to have lower blood levels of vitamin E.

Hygiene

Acne is not caused by dirt. This misconception probably comes from the fact that blackheads look like dirt stuck in the openings of pores. The black color is not dirt but simply oxidised keratin. In fact, the blockages of keratin that cause acne occur deep within the narrow follicle channel, where it is impossible to wash them away. These plugs are formed by the failure of the cells lining the duct to separate and flow to the surface in the sebum created there by the body. Built up oil of the skin can block the passages of these pores, so standard washing of the face could wash off old oil and help unblock the pores.

Treatments

Available treatments

There are many products available for the treatment of acne, many of which are without any scientifically-proven effects. Generally speaking, successful treatments show little improvement within the first two weeks, instead taking a period of approximately three months to improve and start flattening out. Many treatments that promise big improvements within two weeks are likely to be largely disappointing. However, short bursts of cortisone can give very quick results, and other treatments can rapidly improve some active spots, but usually not all active spots.

Modes of improvement are not necessarily fully understood but in general treatments are believed to work in at least 4 different ways (with many of the best treatments providing multiple simultaneous effects):

• normalising shedding into the pore to prevent blockage
• killing P. acnes
• antinflammatory effects
• hormonal manipulation

Topical bactericidals

Widely available OTC bactericidal products containing benzoyl peroxide may be used in mild to moderate acne. The gel or cream containing benzoyl peroxide is rubbed, twice daily, into the pores over the affected region. Bar soaps or washes may also be used and vary from 2 to 10% in strength. In addition to its therapeutic effect as a keratolytic (a chemical that dissolves the keratin plugging the pores) benzoyl peroxide also prevents new lesions by killing P.acnes. In one study, roughly 70% of participants using a 10% benzoyl peroxide solution experienced a reduction in acne lesions after 6 weeks.Unlike antibiotics, benzoyl peroxide has the advantage of being a strong oxidizer (essentially a mild bleach) and thus does not appear to generate bacterial resistance. However, it routinely causes dryness, local irritation and redness. A sensible regimen may include the daily use of low-concentration (2.5%) benzoyl peroxide preparations, combined with suitable non-comedogenic moisturisers to help avoid overdrying the skin.

Topical antibiotics

Externally applied antibiotics such as erythromycin, clindamycin, Stiemycin, or tetracycline aim to kill the bacteria that are harbored in the blocked follicles. While topical use of antibiotics is equally as effective as oral use, this method avoids possible side effects including upset stomach and drug interactions (e.g. it will not affect use of the oral contraceptive pill), but may prove awkward to apply over larger areas than just the face alone.

Oral antibiotics

Oral antibiotics used to treat acne include erythromycin or one of the tetracycline antibiotics (tetracycline, the better absorbed oxytetracycline, or one of the once daily doxycycline, minocycline, or lymecycline). Trimethoprim is also sometimes used (off-label use in UK). However, reducing the P. acnes bacteria will not, in itself, do anything to reduce the oil secretion and abnormal cell behaviour that is the initial cause of the blocked follicles. Additionally the antibiotics are becoming less and less useful as resistant P. acnes are becoming more common. Acne will generally reappear quite soon after the end of treatment—days later in the case of topical applications, and weeks later in the case of oral antibiotics.

Hormonal treatments

In females, acne can be improved with hormonal treatments. The common combined oestrogen/progestogen methods of hormonal contraception have some effect, but the antiandrogen, Cyproterone, in combination with an oestrogen (Diane 35) is particularly effective at reducing androgenic hormone levels. Diane-35 is not available in the USA, but a newer oral contraceptive containing the progestin drospirenone is now available with fewer side effects than Diane 35 / Dianette. Both can be used where blood tests show abnormally high levels of androgens, but are effective even when this is not the case. Along with this, treatment with low dose spironolactone can have anti-androgenetic properties, especially in patients with polycystic ovarian syndrome.

Biological Treatment

A number of biological treatments available when suffering from this skin condition contain mucin from the snail Helix aspersa müller. This substance contains glycoconjugates (complex glycan or sugar molecules bound to proteins, enzymes, co-enzymes, peptides, and oligoelements). The enzymes unclog pores and get rid of debris and dead cells, the peptides act as antimicrobials and the glycomolecules are skin repairing substances that prevent and heal acne breakouts and acne skin lesions and scarring. The secretion from the Helix aspersa müller regulates the skin healing and how acne is formed. These topical treatments focus on the creation of skin cells instead of aggravating the body's inflammatory immune system response. The ingredients can saturate deep into the skin and promote cellular turnover. The waste material is removed from the skin lesions so as to reduce inflammation, speed up the healing process and encourage regeneration of new tissue. Biological ingredients with active parts like antioxidants, anti-inflammatory, proteins, peptides, and enzymes can with rather little effort stimulate the speed in which the body heals the acne outbursts.

Topical retinoids

A group of medications for normalizing the follicle cell lifecycle are topical retinoids such as tretinoin (brand name Retin-A), adapalene (brand name Differin), and tazarotene (brand name Tazorac). Like isotretinoin, they are related to vitamin A, but they are administered as topicals and generally have much milder side effects. They can, however, cause significant irritation of the skin. The retinoids appear to influence the cell creation and death lifecycle of cells in the follicle lining. This helps prevent the hyperkeratinization of these cells that can create a blockage. Retinol, a form of vitamin A, has similar but milder effects and is used in many over-the-counter moisturizers and other topical products. Effective topical retinoids have been in use over 30 years but are available only on prescription so are not as widely used as the other topical treatments. Topical retinoids often cause an initial flare up of acne and facial flushing.

Oral retinoids

A daily oral intake of vitamin A derivative isotretinoin (marketed as Accutane, Amnesteem, Sotret, Claravis) over a period of 4-6 months can cause long-term resolution or reduction of acne. It is believed that isotretinoin works primarily by reducing the secretion of oils from the glands, however some studies suggest that it affects other acne-related factors as well. Isotretinoin has been shown to be very effective in treating severe acne and can either improve or clear well over 80% of patients. The drug has a much longer effect than anti-bacterial treatments and will often cure acne for good. The treatment requires close medical supervision by a dermatologist because the drug has many known side effects (many of which can be severe). About 25% of patients may relapse after one treatment. In those cases, a second treatment for another 4-6 months may be indicated to obtain desired results. It is often recommended that one lets a few months pass between the two treatments, because the condition can actually improve somewhat in the time after stopping the treatment and waiting a few months also gives the body a chance to recover. Occasionally a third or even a fourth course is used, but the benefits are often less substantial. The most common side effects are dry skin and occasional nosebleeds (secondary to dry nasal mucosa). Oral retinoids also often cause an initial flare up of acne within a month or so, which can be severe. There are reports that the drug has damaged the liver of patients. For this reason, it is recommended that patients have blood samples taken and examined before and during treatment. In some cases, treatment is terminated or reduced due to elevated liver enzymes in the blood, which might be related to liver damage. Others claim that the reports of permanent damage to the liver are unsubstantiated, and routine testing is considered unnecessary by some dermatologists. Blood triglycerides also need to be monitored. However, routine testing are part of the official guidelines for the use of the drug in many countries. Some press reports suggest that isotretinoin may cause depression but as of September 2005 there is no agreement in the medical literature as to the risk. The drug also causes birth defects if women become pregnant while taking it or take it while pregnant. For this reason, female patients are required to use two separate forms of birth control or vow abstinence while on the drug. Because of this, the drug is supposed to be given to females as a last resort after milder treatments have proven insufficient. Restrictive rules (see iPledge Program) for use were put into force in the USA beginning in March 2006 to prevent misuse. This has occasioned widespread editorial comment.

Phototherapy

'Blue' and red light

It has long been known that short term improvement can be achieved with sunlight. However, studies have shown that sunlight worsens acne long-term. More recently, visible light has been successfully employed to treat acne (phototherapy) - in particular intense violet light (405-420nm) generated by purpose-built fluorescent lighting, dichroic bulbs, LEDs or lasers. Used twice weekly, this has been shown to reduce the number of acne lesions by about 64%; and is even more effective when applied daily. The mechanism appears to be that a porphyrin (Coproporphyrin III) produced within P. acnes generates free radicals when irradiated by 420nm and shorter wavelengths of light. Particularly when applied over several days, these free radicals ultimately kill the bacteria. Since porphyrins are not otherwise present in skin, and no UV light is employed, it appears to be safe, and has been licensed by the U.S. FDA. The treatment apparently works even better if used with red visible light (660 nanometer) resulting in a 76% reduction of lesions after 3 months of daily treatment for 80% of the patients; and overall clearance was similar or better than benzoyl peroxide. Unlike most of the other treatments few if any negative side effects are typically experienced, and the development of bacterial resistance to the treatment seems very unlikely. After treatment, clearance can be longer lived than is typical with topical or oral antibiotic treatments; several months is not uncommon. The equipment or treatment, however, is relatively new and reasonably expensive to buy initially, although the total cost of ownership can be similar to many other treatment methods (such as the total cost of benzoyl peroxide, moisturiser, washes) over a couple of years of use.

Photodynamic therapy

In addition, basic science and clinical work by dermatologists Yoram Harth and Alan Shalita and others has produced evidence that intense blue/violet light (405-425 nanometer) can decrease the number of inflammatory acne lesion by 60-70% in 4 weeks of therapy, particularly when the P.acnes is pretreated with delta-aminolevulinic acid (ALA), which increases the production of porphyrins. However this photodynamic therapy is controversial and apparently not published in a peer reviewed journal.

Laser treatment

Laser surgery has been in use for some time to reduce the scars left behind by acne, but research has been done on lasers for prevention of acne formation itself. The laser is used to produce one of the following effects:

• to burn away the follicle sac from which the hair grows
• to burn away the sebaceous gland which produces the oil
• to induce formation of oxygen in the bacteria, killing them

Less widely used treatments

• Aloe vera: there are treatments for acne mentioned in Ayurveda using herbs such as Aloe vera, Aruna, Haldi (Turmeric),and Papaya. There is limited evidence from conventional medical studies on these products. Products from Rubia cordifolia, Curcuma longa (commonly known as Turmeric), Hemidesmus indicus (known as ananthamoola or anantmula), and Azadirachta indica (Neem) have been shown to have anti-inflammatory effects, but not aloe vera.
• Azelaic acid (brand names Azelex, Finevin, Skinoren) is suitable for mild, comedonal acne.
• Heat: local heating may be used to kill the bacteria in a developing pimple and so speed healing.
• Naproxen or ibuprofen are used for some moderate acne for their anti-inflammatory effect.
• Nicotinamide, (Vitamin B3) used topically in the form of a gel, has been shown in a 1995 study to be more effective than a topical antibiotic used for comparison, as well as having fewer side effects. Topical nicotinamide is available both on prescription and over-the-counter. The property of topical nicotinamide's benefit in treating acne seems to be its anti-inflammatory nature. It is also purported to result in increased synthesis of collagen, keratin, involucrin and flaggrin.
• Tea Tree Oil (Melaleuca Oil) has been used with some success, comparable to benzoyl peroxide but without excessive drying, and has been shown to be an effective anti-inflammatory in skin infections.
• Rofecoxib was shown to improve premenstrual acne vulgaris in a placebo controlled study.
• Zinc: Orally administered zinc gluconate has been shown to be effective in the treatment of inflammatory acne, although less so than tetracyclines.
• Honey: Honey is one of the strongest naturally occurring antibiotics. When placed on the skin like a mask for 20 minutes and washed off with hot water, the results over the next day should be pleasing. [citation needed]

History of some acne treatments

The history of acne reaches back to the dawn of recorded history. In Ancient Egypt, it is recorded that several pharaohs were acne sufferers. From Ancient Greece comes the English word 'acne' (meaning 'point' or 'peak'). Acne treatments are also of considerable antiquity:

• Ancient Rome: bathing in hot, and often sulfurous, mineral water was one of the few available acne treatments. One of the earliest texts to mention skin problems is De Medicina by the Roman writer Celsus.
• 1800s: Nineteenth century dermatologists used sulphur in the treatment of acne. It was believed to dry the skin.
• 1920s: Benzoyl Peroxide is used
• 1930s: Laxatives were used as a cure for what were known as 'chastity pimples'. Radiation also was used.
• 1950s: When antibiotics became available, it was discovered that they had beneficial effects on acne. They were taken orally to begin with. Much of the benefit was not from killing bacteria but from the anti-inflammatory effects of tetracycline and its relatives. Topical antibiotics became available later.
• 1970s: Tretinoin (original Trade Name Retin A) was found effective for acne. This preceded the development of oral isotretinoin (sold as Accutane and Roaccutane) in 1980.
• 1980s: Accutane is introduced in America, and later found to be a teratogen, highly likely to cause birth defects if taken during pregnancy. In the United States more than 2,000 women became pregnant while taking the drug between 1982 and 2003, with most pregnancies ending in abortion or miscarriage. About 160 babies with birth defects were born.
• 1990s: Laser treatment introduced
• 2000s: Blue/red light therapy

Future treatments

A 2007 microbiology article reporting the first genome sequencing of a Propionibacterium acnes bacteriophage (PA6) said this "should greatly enhance the development of a potential bacteriophage therapy to treat acne and therefore overcome the significant problems associated with long-term antibiotic therapy and bacterial resistance."

Preferred treatments by types of acne vulgaris

• Comedonal (non-inflammatory) acne: local treatment with azelaic acid, salicylic acid, topical retinoids, benzoyl peroxide.
• Mild papulo-pustular (inflammatory) acne: benzoyl peroxide or topical retinoids, topical antibiotics (such as erythromycin).
• Moderate inflammatory acne: benzoyl peroxide or topical retinoids combined with oral antibiotics (tetracyclines). Isotretinoin is an option.
• Severe inflammatory acne, nodular acne, acne resistant to the above treatments: isotretinoin also known as Acutane, can be prescribed by a doctor, or contraceptive pills with cyproterone for females with virilization or drospirenone.

Acne scars

See Acne scarring.

Pigmentation

Pigmented scars is a slightly misleading term as it suggests a change in the skin's pigmentation and that they are true scars; however, neither is true. Pigmented scars are usually the result of nodular or cystic acne (the painful 'bumps' lying under the skin). They often leave behind an inflamed red mark. Often, the pigmentation scars can be avoided simply by avoiding aggravation of the nodule or cyst. When sufferers try to 'pop' cysts or nodules, pigmentation scarring becomes significantly worse, and may even bruise the affected area. Pigmentation scars nearly always fade with time taking between 3 months to two years to do so, although rarely can persist.

Grading scale

There are multiple grading scales for grading the severity of acne vulgaris, three of these being: Leeds acne grading technique: Counts and categorises lesions into inflammatory and non-inflammatory (ranges from 0-10.0). Cook's acne grading scale: Uses photographs to grade severity from 0 to 8 (0 being the least severe and 8 being the most severe). Pillsbury scale: Simply classifies the severity of the acne from 1 (least severe) to 4 (most severe).

See also

• Blackhead
• Keratosis pilaris
• Rosacea
• Chloracne
• Feline acne

Footnotes

Further reading

Review articles and guidelines

• http://www.bmj.com/cgi/reprint/325/7362/475.pdf
• http://www.aafp.org/afp/20040501/2123.pdf
• http://jama.ama-assn.org/cgi/reprint/292/6/726.pdf
• http://blues.sabinet.co.za/WebZ/Authorize?sessionid=0:autho=pubmed:password=pubmed2004&/AdvancedQuery?&format=F&next=images/ejour/m_samj/m_samj_v95_n11_a21.pdf
• http://pediatrics.aappublications.org/cgi/reprint/118/3/1188.pdf

Reference books and chapters

• Acne and rosacea
• Acne : diagnosis and management
• Fitzpatrick's dermatology in general medicine
• Dermatology
• Clinical dermatology : a color guide to diagnosis and therapy
• Rook's textbook of dermatology
• Andrews' diseases of the skin : clinical dermatology

External links

• Acne vulgaris: more than skin deep (on the psychological effects of acne)
• Acne Library of publications
• Acne, Zits, Pimples & how to fight it!
• Acne photo library at Dermnet
• Story on Acne from the Better Health Channel (Quality assured by the Victorian government, Australia)
• - Dermatologist-reviewed information about acne.
• Q&A about Acne, from the National Institutes of Health.
• Acne myths vs. facts, Myths and facts about acne.

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