Acne vulgaris (or
cystic acne) is a common
human skin disease, characterized by areas of skin with
seborrhea (scaly red skin),
comedones (blackheads and whiteheads),
papules (pinheads),
pustules (
pimples),
Nodules (large papules) and possibly scarring.
[1] Acne affects mostly skin with the densest population of sebaceous follicles; these areas include the face, the upper part of the chest, and the back. Severe acne is
inflammatory, but acne can also manifest in noninflammatory forms.
[2] The lesions are caused by changes in pilosebaceous units, skin structures consisting of a
hair follicle and its associated
sebaceous gland, changes that require
androgen stimulation.
Acne occurs most commonly during
adolescence, and often continues into adulthood. In adolescence, acne is usually caused by an increase in
testosterone, which people of both genders accrue during puberty.
[3] For most people, acne diminishes over time and tends to disappear — or at the very least decrease — after one reaches one's early twenties. There is, however, no way to predict how long it will take to disappear entirely, and some individuals will carry this condition well into their thirties, forties, and beyond.
[4]
Some of the large nodules were previously called "
cysts" and the term
nodulocystic has been used to describe severe cases of inflammatory acne.
[5] The "cysts," or
boils that accompany cystic acne, can appear on the buttocks, groin, and armpit area, and anywhere else where sweat collects in hair follicles and perspiration ducts.
[6] Cystic acne affects deeper skin tissue than does common acne.
[7]
Aside from scarring, its main effects are psychological, such as reduced
self-esteem[8] and in very extreme cases,
depression or
suicide.
[9] Acne usually appears during
adolescence, when people already tend to be most socially insecure. Early and aggressive treatment is therefore advocated by some to lessen the overall long-term impact to individuals.
[8]
Terminology
The term
acne comes from a corruption of the
Greek ἀκμή (
akmē), literally "point, edge", but in the sense of a "skin eruption"
[10] in the writings of
Aëtius Amidenus. Used by itself, the term "acne" refers to the presence of
pustules and
papules.
[11] The most common form of acne is known as acne vulgaris, meaning "common acne". Many teenagers get this type of acne. Use of the term "acne vulgaris" implies the presence of
comedones.
[12]
The term "acne rosea" is a synonym for
rosacea, however some individuals may have almost no acne comedones associated with their rosacea and prefer therefore the term rosacea.
[13] Chloracne is associated with exposure to
polyhalogenated compounds.
Signs and symptoms
Typical features of acne include:
seborrhea (scaly red skin),
comedones (blackheads and whiteheads),
papules (pinheads),
pustules (
pimples),
nodules (large papules) and, possibly scarring.
[1] It presents somewhat differently in people with dark skin.
Scars
Acne
scars are the result of inflammation within the dermis brought on by acne. The scar is created by the wound trying to heal itself resulting in too much collagen in one spot.
[14]
Physical acne scars are often referred to as "Icepick" scars. This is because the scars tend to cause an indentation in the skin's surface. There are a range of treatments available. Although quite rare, the medical condition
Atrophia Maculosa Varioliformis Cutis also results in "acne-like" depressed scars on the face.
- Ice pick scars: Deep pits, that are the most common and a classic sign of acne scarring.
- Box car scars: Angular scars that usually occur on the temple and cheeks, and can be either superficial or deep, these are similar to chickenpox scars.
- Rolling scars: Scars that give the skin a wave-like appearance.
- Hypertrophic scars: Thickened, or keloid scars.
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. Pigmentation scars nearly always fade with time taking between three months to two years to do so, although can last forever if untreated.
-
A severe case of cystic acne
-
-
Different types of Acne Vulgaris: A: Cystic acne on the face, B: Subsiding tropical acne of trunk, C: Extensive acne on chest and shoulders.
Cause
Acne develops as a result of blockages in
follicles.
Hyperkeratinization and formation of a plug of
keratin and
sebum (a
microcomedo) is the earliest change. Enlargement of sebaceous glands and an increase in sebum production occur with increased
androgen (
DHEA-S) production at
adrenarche. The microcomedo may enlarge to form an open comedone (
blackhead) or closed comedone (milia). Comedones are the direct result of
sebaceous glands' becoming clogged with
sebum, a naturally occurring oil, and dead skin cells. In these conditions, the naturally occurring largely
commensal bacterium
Propionibacterium acnes can cause
inflammation, leading to inflammatory lesions (
papules, infected pustules, or nodules) in the
dermis around the microcomedo or comedone, which results in redness and may result in
scarring or
hyperpigmentation.
[15]
Hormonal Hormonal activity, such as
menstrual cycles and
puberty, may contribute to the formation of acne. During puberty, an increase in male sex hormones called androgens cause the follicular glands to grow larger and make more sebum.
[16] Use of
anabolic steroids may have a similar effect.
[17] Several
hormones have been linked to acne: the androgens
testosterone,
dihydrotestosterone (DHT) and
dehydroepiandrosterone sulfate (DHEAS), as well as
insulin-like growth factor 1 (IGF-I).
Development of acne vulgaris in later years is uncommon, although this is the age group for
rosacea, which may have similar appearances. True acne vulgaris in adult women may be a feature of an underlying condition such as pregnancy and disorders such as
polycystic ovary syndrome or the rare
Cushing's syndrome. Menopause-associated acne occurs as production of the natural anti-acne ovarian hormone
estradiol fails at menopause. The lack of estradiol also causes thinning hair, hot flushes, thin skin, wrinkles, vaginal dryness, and predisposes to osteopenia and osteoporosis as well as triggering acne (known as acne climacterica in this situation).
Genetic
The tendency to develop acne runs in families. For example, school aged boys with acne often have other members in their family with acne. A family history of acne is associated with an earlier occurrence of acne and an increased number of retentional acne lesions.
[18]
Psychological
While the connection between acne and stress has been debated, scientific research indicates that "increased acne severity" is "significantly associated with increased stress levels."
[19] The National Institutes of Health (USA) list stress as a factor that "can cause an acne flare."
[20] A study of adolescents in Singapore "observed a statistically significant positive correlation […] between stress levels and severity of acne."
[21] It is also not clear whether acne causes stress and thus perpetuates itself to some extent.
Infectious
Propionibacterium acnes (P. acnes) is the anaerobic bacterium species that is widely concluded to cause acne, though
Staphylococcus epidermidis has been universally discovered to play some role since normal pores appear colonized only by P.acnes.
[22] Regardless, there are specific clonal sub-strains of P.acnes associated with normal skin health and others with long-term acne problems. It is as yet inconclusive whether any of these undesirable strains evolve on-site in the adverse conditions or are all pathogenically acquired, or possibly either depending on the individual patient. These strains either have the capability of changing, perpetuating, or adapting to, the abnormal cycle of inflammation, oil production, and inadequate sloughing activities of acne pores. At least one particularly virulent strain, though, has been circulating around Europe for at least 87 years.
[23]In vitro, resistance of
P. acnes to commonly used antibiotics has been increasing, as well.
[24]
Diet
A high
glycemic load diet is associated with worsening acne.
[25] There is also an association between the consumption of milk and the rate and severity of acne.
[25][26] Other associations such as
chocolate and
salt are not supported by the evidence.
[25] However, products with these ingredients often contain a high glycemic load.
Diagnosis
There are multiple grading scales for grading the severity of acne vulgaris,
[27] 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).
Differential
Management
Many different treatments exist for acne including
benzoyl peroxide, antibiotics,
retinoids, antiseborrheic medications, anti-androgen medications,
hormonal treatments,
salicylic acid,
alpha hydroxy acid,
azelaic acid,
nicotinamide, and keratolytic soaps.
[28] They are believed to work in at least 4 different ways, including: normalising shedding into the pore to prevent blockage, killing
Propionibacterium acnes, anti-inflammatory effects, hormonal manipulation.
[citation needed]
Exercise
Increased blood flow following exercise assists the maintenance of skin cells as it brings in oxygen and nutrients while removing waste. A secondary effect of exercise on acne is that it can reduce stress.
[29]
Medications
- Benzoyl peroxide
Benzoyl peroxide is a first-line treatment for mild and moderate acne vulgaris due to its effectiveness and mild side-effects (primarily an irritant
dermatitis). It works against the "P. acnes" bacterium, and normally causes just dryness of the skin, slight redness, and occasional peeling when side-effects occur.
[30] This topical does increase sensitivity to the sun as indicated on the package, so sunscreen should be used during the treatment to prevent sunburn. Benzoyl peroxide has been found to be nearly as effective as antibiotics with all concentrations 2.5%, 5.0%, and 10% equally effective.
[30] Unlike antibiotics, benzoyl peroxide does not appear to generate bacterial resistance.
[30]
- Antibiotics
Antibiotics are reserved for more severe cases.
[30] With increasing resistance of
P. acnes worldwide, they are becoming less effective.
[30] Commonly used antibiotics, either applied topically or taken orally, include
erythromycin,
clindamycin, and
tetracyclines such as
minocycline.
- Hormones
In females, acne can be improved with
hormonal treatments. The common combined
estrogen/
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.
- Topical retinoids
A group of medications for normalizing the follicle cell life-cycle are
topical retinoids such as
tretinoin (Retin-A),
adapalene (Differin), and
tazarotene (Tazorac). Like isotretinoin, they are related to
vitamin A, but they are administered as topicals and, in general, have much milder side-effects. They can, however, cause significant irritation of the skin. The retinoids appear to influence the cell creation and death life-cycle 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 for 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 Roaccutane, Accutane, Amnesteem, Sotret, Claravis, Clarus) 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 let 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. On occasion, 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
[weasel words] 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, causing occasioned widespread editorial comment.
[31]
- Anti-inflammatories
Nicotinamide, (vitamin B
3) used topically in the form of a gel, has been shown in a 1995 study to be of comparable efficacy to topical clindamycin used for comparison.
[32] 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, and may also, according to a cosmetic company, be useful for reducing skin hyperpigmentation (acne scars), increasing skin moisture and reducing fine wrinkles.
[33]
Ibuprofen in combination with
tetracycline[34] are used for some moderate acne cases for their anti-inflammatory effects.
Mandelic acid has been noted to be an effective topical treatment for mild to moderate acne. It is considered to be a gentler alternative to popular alpha hydroxy acids, such as
glycolic acid and lactic acid.
[35]
Procedures
Dermabrasion
Dermabrasion is a
cosmetic medical procedure in which the surface of the
skin is removed by abrasion (sanding). It is used to remove sun-damaged skin and to remove or lessen
scars and dark spots on the skin. The procedure is very painful and usually requires a
general anaesthetic or "twilight anaesthesia", in which the patient is still partly conscious.
[4] Afterward, the skin is very red and raw-looking, and it takes several months for the skin to regrow and heal. Dermabrasion is useful for scar removal when the scar is raised above the surrounding skin, but is less effective with sunken scars.
In the past, dermabrasion was done using a small, sterilized, electric sander. In the past decade, it has become more common to use laser dermabrasion using
CO2,
Er:YAG laser or a combination of both for the treatment of acne scars. Indications for CO
2 laser treatment include previous non erythematous and non-proliferative
hypertrophic scars, atrophic acne
scars and burn scars.
[36] Laser dermabrasion is much easier to control, much easier to gauge, and is practically bloodless compared to classic dermabrasion.
Phototherapy
Blue and red light
Light exposure has long been used as a short-term treatment for acne. Recently, visible light has been successfully employed to treat mild to moderate acne (
phototherapy or
deep penetrating light therapy) - in particular intense violet light (405–420 nm) 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%
[37] 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 420 nm and shorter wavelengths of light.
[38] Particularly when applied over several days, these free radicals ultimately kill the bacteria.
[39] Since porphyrins are not otherwise present in skin, and no UV light is employed, it appears to be safe, and has been cleared for marketing by the
U.S. FDA.
[40][41]
It seems that the treatment works even better if used with a mixture of the violet light and red visible light (660 nanometer), resulting in a 76% reduction of lesions after three months of daily treatment for 80% of the patients;
[42] 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, moisturizer, 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 have produced evidence that intense blue/violet light (405–425 nanometer) can decrease the number of inflammatory acne lesion by 60–70% in four weeks of therapy, in particular, when the
P. acnes is pretreated with
delta-aminolevulinic acid (ALA), which increases the production of porphyrins. However this photodynamic therapy is controversial and not published in a peer-reviewed journal. A phase II trial, while it showed improvement occurred, failed to show improved response compared to the blue/violet light alone.
[43]
Laser treatment
Laser surgery has been in use for some time to reduce the scars left behind by acne,
[44] 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
Since lasers and intense pulsed light sources cause thermal damage to the skin, there are concerns that laser or intense pulsed light treatments for acne will induce hyperpigmented macules (spots) or cause long-term dryness of the skin.
The
FDA has approved the use of a cosmetic laser for the treatment of acne. However, efficacy studies have used very small sample sizes for periods of six months or less, and have shown contradictory results.
[45] Also, laser treatment being relatively new, protocols remain subject to experimentation and revision,
[46] and treatment can be quite expensive. Also, some Smoothbeam laser devices had to be recalled due to coolant failure, which resulted in painful burn injuries to patients.
[47]
Surgery
For people with cystic acne, boils can be drained through
surgical lancing.
[7]
Alternative medicine
- Tea tree oil (melaleuca oil) has been used with some success, where it is comparable to benzoyl peroxide but without excessive drying, kills P. acnes, and has been shown to be an effective anti-inflammatory in skin infections.[48][49][50]
- Aloe vera: there are treatments for acne mentioned in Ayurveda using herbs such as Aloe vera, Neem, Haldi (Turmeric) and Papaya. However, scientific evidence for the cosmetic effectiveness of aloe vera is limited and when present is frequently contradictory.[48][51][52]
Prognosis
Acne usually improves around the age of 20 but may persist into adulthood.
[28]
Epidemiology
Acne affects 40 to 50 million people in the United States (16%), and approximately 3 to 5 million in Australia (23%).
[53] It affects people of all racial and ethnic groups.
[54]
History
- Ancient Egypt and Ancient Greece: Sulfur was used to treat acne.
- 1920s: Benzoyl peroxide was used as a medication to treat acne.
- 1970s: Tretinoin (original Trade Name Retin A) was found effective for acne.[55] This preceded the development of oral isotretinoin (sold as Accutane and Roaccutane) in 1980.[56] Also, antibiotics such as minocycline are used as treatments for acne.
- 1980s: Accutane is introduced in the United States, 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.[57][58]
Research
A vaccine against inflammatory acne has been tested successfully in mice, but it is not certain that it would work similarly in humans.
[59]
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."
[60]
source:http://en.wikipedia.org/wiki/Acne_vulgaris
