diagnose acne vulgaris

Acne vulgaris

How should I diagnose acne vulgaris?

• A person with acne usually presents with a history of troublesome 'spots', most commonly affecting the face, shoulders, back, and chest. The person is most commonly an adolescent or young adult, but acne can occur for the first time in later life.
• Examine all affected areas of skin (including the back and shoulders).
• The skin and hair may have an oily texture and appearance.
• Depending on the severity of the acne, there may be non-inflammatory comedones, inflamed papules or pustules, or a mixture of both.
• Closed comedones (whiteheads) appear as raised bumps on the skins surface, and are skin-coloured or slightly reddened.
• Open comedones (blackheads) have a characteristic black 'plug' caused by oxidised oil and dead skin cells.
• Papules are small, round or oval, inflamed (red), raised elevations of the skin.
• Pustules resemble papules, but have a central pocket of pus.
• Nodules are poorly demarcated swellings that are usually red and tender. They may be fluctuant on palpation. In very severe acne, nodules may track together and form large, deep sinuses (acne conglobata).
• Haemorrhagic acne is caused by bleeding inflammatory lesions, and may be very painful and distressing.
• Look for evidence of scarring and hyperpigmentation.
• Scarring may occur when acne heals, particularly when nodules have been present. It is most commonly atrophic in nature, leading to the formation of 'ice-pick' scars or 'pock marks'.
• Hyperpigmentation may occur after acne resolves, especially in people with darker complexions.
• If the features are atypical of acne vulgaris, consider the possibility of a severe form or clinical variant of acne.
• Images of acne and its clinical variants can be viewed at www.dermnet.org.nz.

[Brown and Shalita, 1998; Thiboutot, 2000; Simpson and Cunliffe, 2004; ICSI, 2006]

Clinical variants

• If acne presents with atypical features, consider the possibility of a rarer form of acne.
• Acne conglobata is very severe acne where inflammatory lesions predominate and run together, often accompanied by exudate or bleeding. This form of acne may cause extensive scarring.
• Acne fulminans is a sudden severe inflammatory reaction that precipitates deep ulcerations and erosions, sometimes with systemic effects (such as fever and arthralgia).
• Acne excoriée mainly affects young women and is characterized by self-inflicted wounds. It is primarily a psychological or emotional problem.
• Acne mechanica is caused secondarily to pressure, friction, or rubbing from clothing (such as a mask or hat).
• Acne cosmetica is caused by contact of the skin with comedogenic products.
• Chloracne is caused by occupational exposure to halogenated hydrocarbons. It is characterized by the presence of numerous, large comedones.

Basis for recommendation

Recommendations for the diagnosis of acne vulgaris and its clinical variants are based on an international guideline [ICSI, 2006] and expert opinion from narrative reviews [Brown and Shalita, 1998; Thiboutot, 2000;Wolf, 2002; Simpson and Cunliffe, 2004].

What else might it be?

• Acne vulgaris is rarely misdiagnosed. Conditions which may mimic the signs of acne include:
• Rosacea is the condition most commonly mistaken for acne vulgaris. It usually occurs in older people and its main symptom is flushing and the presence of inflammatory papules, with a central facial distribution. However, there is an absence of comedones, nodules, or scarring. 
• Folliculitis and boils may present with pustular lesions similar to those seen in acne. Swabs usually yieldStaphylococcus aureus. Sycosis barbae is persistent folliculitis of the beard area. 
• Milia are small keratin cysts that may be confused with whiteheads. They tend to be whiter than acne whiteheads, they do not have a central punctum, and they are most commonly found around the eyes.
• Perioral dermatitis presents as erythema and small papules around the mouth, nasolabial folds, and sometimes the lower eyelids. It can have both eczematous and acneiform features, and when acneiform features predominate it may be mistaken for acne. In these cases, the perioral distribution gives the best clue as to its nature.
• Demodex folliculitis is caused by mites and usually occurs in older people. It predominantly affects the face.
• Pityrosporum folliculitis is caused by a yeast-like organism. It tends to affect younger people and predominates on the trunk.

Basis for recommendation

Information on the differential diagnosis of acne vulgaris is from expert opinion described in narrative reviews[Healy and Simpson, 1994; Layton, 2000; Thiboutot, 2000; Wolf, 2002].

How should I investigate the cause of acne in a woman?

• Diagnostic investigations are not necessary for the management of acne vulgaris unless it is suspected as being secondary to an underlying cause in women. Hyperandrogenism should be suspected if the woman has:
• Irregular periods, androgenic alopecia (hair thinning on the front of the scalp), or excessive facial or body hair (hirsutism).
• Acne resistant to conventional treatment (including oral antibiotics), or there is a rapid relapse after a course of oral isotretinoin.
• A sudden onset of severe acne.
• If hyperandrogenism is suspected, consider the following investigations:
• Total and free testosterone — elevated levels may indicate polycystic ovarian syndrome (PCOS) or, rarely, ovarian cancer.
• Luteinizing hormone/follicle-stimulating hormone (LH/FSH) ratio — may be altered in PCOS, with elevated LH.
• Serum dehydroepiandrosterone (DHEA) — elevated levels may indicate adrenal tumour or congenital adrenal hyperplasia.
• 17-hydroxyprogesterone — elevated levels may indicate congenital adrenal hyperplasia.
• Prolactin — may reveal hyperprolactinaemia.
• 24 hour urinary-free cortisol — elevated levels may indicated Cushing's disease or syndrome.

Basis for recommendation

Recommendations for suspecting and investigating hyperandrogenism in women is based on opinion from expert reviews [James, 2005; Ravenscroft, 2005].

How should I assess a person with acne?

• Ask about the problems the person has experienced with their acne. Enquire about:
• The reasons for the person presenting, how long they have had acne, and whether it is worsening.
• Any treatments the person has already tried (for example over-the-counter medication).
• Possible causes or aggravating factors (for example, occupational exposure to halogenated hydrocarbons).
• In women, consider whether the acne could be secondary to a hormonal cause. Features of hyperandrogenism include: irregular periods; androgenic alopecia or hirsutism; acne resistant to conventional treatment (or relapse immediately after a course of oral isotretinoin); and premenstrual flares of acne or a sudden onset of severe acne.
• Assess the severity of the acne. Physically, acne can be categorized as mild, moderate, or severe, but other factors, such as the extent of acne and evidence of scarring, should also be considered.
• Mild acne predominantly consists of non-inflammatory comedones.
• Moderate acne consists of a mixture of non-inflammatory comedones and inflammatory papules and pustules.
• Severe acne is characterized by the presence of nodules and cysts, as well as a preponderance of inflammatory papules and pustules.
• Scarring often indicates previous episodes of severe acne (its presence may warrant more aggressive treatment to prevent further scarring).
• Acne conglobata and acne fulminans are severe variants that require immediate referral.
• Ask about the psychosocial impact of the acne (such as problems at work or school). If the psychological impact seems to be particularly severe or disproportionate, consider using a validated quality of life scale, such as the Cardiff Acne Disability Index (which can be downloaded from www.dermatology.org.uk). This can be used to monitor the person's psychological state during subsequent management.

Basis for recommendation

These recommendations are based on expert opinion from international guidelines [ICSI, 2006; Strauss et al, 2007] and narrative reviews [Webster, 2002; Wolf, 2002; James, 2005; Ravenscroft, 2005; Acne Working Group, 2008].

Categorizing acne severity

• There is no universal grading system for the classification of acne severity [Strauss et al, 2007]. Grading systems have largely been developed for use in clinical trials and rely on lesion counts, but these are generally not suitable for clinical practice [Webster, 2002]. However, there is general consensus from experts that it is useful to categorize acne into three severity grades in order to guide management of the condition.

Psychosocial impact of acne

• During assessment, it is important to recognize the psychosocial impact of acne. It can have a severe negative impact on the person's life. Although often the person tends to overestimate the severity of their acne, the healthcare professional tends to underestimate it. Estimating the physical severity of acne alone is insufficient to guide management, as it may be appropriate to treat acne associated with a greater psychosocial impact more aggressively, or refer the person [Acne Working Group, 2008]

Treatment of Mild Acne:

What information should I give about acne?

• Reassure the person about the natural course of the condition, but do not trivialize it. Advise that:
• Acne is one of the most common disorders, affecting nearly everyone at some point in their life.
• Acne will improve. It is primarily a skin disorder of the young, and will usually clear up in later life without leaving significant scarring.
• Treatments are effective but take time to work (typically up to 8 weeks) and may irritate the skin, especially at the start of treatment.
• Dispel popular myths about acne. In particular inform the person that:
• Acne is not caused by poor hygiene, and there is no evidence it is improved by cleaning. In fact, excessive washing can aggravate acne.
• Diet has little or no effect on acne. For example, there is no evidence that chocolate or fatty foods cause or aggravate acne. However if the person notices that a particular food triggers flares of acne then it is reasonable to avoid it.
• Picking at acne does not improve it, and may cause scarring. Occasionally it may be beneficial to drain large purulent lesions, but this should be done under medical supervision.
• Stress probably does not cause acne, although there is a correlation between stress and acne, and unsightly lesions may cause increased levels of stress.
• Acne is not infectious and cannot be passed on to other people. The main bacterium involved in the inflammation, Propionibacteria acnes, is naturally present on skin but, in acne, it colonizes follicles.
• Sunlight probably has little benefit in acne, and there is no evidence to support active sunbathing or exposure to other sources of ultraviolet light. Excessive sun exposure should be avoided by all people, especially when taking drugs such as topical or oral retinoids, or oral tetracyclines.

What self-care advice should I give to a person with acne?

• Advise about washing and skin care. In general, it is recommended that people with acne:
• Do not wash more than twice a day.
• Use a mild soap or cleanser and lukewarm water (as very hot or cold water may worsen acne).
• Do not use vigorous scrubbing when washing acne-affected skin, and the use of abrasive soaps, cleansing granules, astringents, or exfoliating agents should be discouraged (advise use of a soft wash-cloth and fingers instead).
• Should not attempt to 'clean' blackheads. Scrubbing or picking acne is liable to worsen the condition.
• Ideally, should avoid excessive use of makeup and cosmetics. If they must be used, advise that a non-comedogenic, water-based product should be used sparingly (advise that details of cosmetic ingredients are displayed on the product label), and that all makeup should be removed completely at night.
• Use a fragrance-free, water-based emollient if dry skin is a problem (several topical acne drugs dry the skin). The use of ointments or oil-rich creams should be avoided as these can clog pores.
• Advise about non-prescription treatments.
• Benzoyl peroxide is a useful topical drug available over-the-counter. However, there is a lack of evidence of benefit for other over-the-counter drugs.
• Complementary and alternative medicines (for example herbal medicines) are not usually harmful but there is a general lack of evidence to support their use.

How should I treat mild acne?

• In mild acne, open and closed comedones (blackheads and whiteheads) predominate. Although the physical severity of the condition is limited and scarring is unlikely, the psychosocial impact may be disproportionate in some people, which is an indication for more aggressive treatment.
• Prescribe a single topical treatment.
• Prescribe a topical retinoid (tretinoin, isotretinoin, or adapalene) or benzoyl peroxide (especially if papules and pustules are present) as first-line treatment.
• Prescribe a topical antibiotic or azelaic acid if both topical retinoids and benzoyl peroxide are poorly tolerated.
• Combined treatment is rarely necessary for mild acne.
• Consider prescribing a standard combined oral contraceptive in women who require contraception, particularly if the acne is having a negative psychosocial impact.

How should I follow up a person with acne?

• Arrange follow up after about 6 weeks, and review the effectiveness and tolerability of treatment, as well as compliance with regimens.
• Advise the person to return sooner if the acne deteriorates significantly despite treatment.

What should I do if mild acne fails to respond to treatment?

• Check adherence to treatment.
• If adherence is poor, this may be because the treatment is poorly tolerated. Consider:
• Reducing the strength of treatment (for example, reducing from 5% to 2.5% benzoyl peroxide).
• Switching to an alternative topical drug that causes less irritation (for example a topical antibiotic or azelaic acid).
• Using a different formulation of drug (for example a cream instead of a drug with an alcoholic base).
• If adherence is adequate, consider:
• Increasing the drug strength and/or frequency of application.
• Combining different topical products (if not already doing so). Benzoyl peroxide combined with erythromycin or clindamycin is particularly effective against both non-inflammatory and inflammatory acne.

When should I refer a person with mild acne?

• People who have severe psychosocial problems, including a morbid fear of deformity (body dysmorphic disorder), or people who have suicidal ideation, should be referred soonto psychiatry.
• Refer for a routine appointment:
• To endocrinology or gynaecology, those women suspected of having an underlying endocrinological cause of acne (such as polycystic ovary syndrome) that needs assessment.
• To dermatology, people with features that make the diagnosis uncertain.

How should I treat moderate acne?

• In moderate acne, inflammatory lesions (papules and pustules) predominate. The acne may be widespread, there may be a risk of scarring, and there may be considerable psychosocial morbidity, all of which are indications for aggressive treatment.
• Treatment options are a single topical drug, a combination of topical drugs, or oral antibiotics.
• Consider a single topical drug in people with limited acne which is unlikely to scar.
• Prescribe benzoyl peroxide or a topical retinoid first-line as they are most effective against inflammatory acne. However, topical retinoids are also effective, and azelaic acid may is an option if other drugs are poorly tolerated.
• Combined treatment should be considered in all people with moderate acne.
• Benzoyl peroxide combined with a topical antibiotic is the usual preferred regimen, as it is proven to be effective and may limit the development of bacterial resistance.
• Other options include a topical retinoid combined with benzoyl peroxide (but this may be poorly tolerated) or a topical retinoid combined with a topical antibiotic (but this may promote bacterial resistance).
• Consider prescribing an oral antibiotic (tetracycline, oxytetracycline, doxycycline, lymecycline, or erythromycin) if topical treatment cannot be tolerated, if there is moderate acne on the back or shoulders (where it may be particularly extensive or difficult to reach), or if there is a significant risk of scarring or substantial pigment change.
• Consider prescribing a standard combined oral contraceptive in women who require contraception
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• How should I treat severe acne?
• • In severe acne, there are nodules and cysts (nodulocystic acne), as well as a preponderance of inflammatory papules and pustules. There is a high risk of scarring (or scarring may already be evident), and there is likely to be considerable psychosocial morbidity.
  • Refer all people with severe acne for specialist assessment and treatment (for example with oral isotretinoin), and consider prescribing an oral antibiotic in combination with a topical drug whilst waiting for an appointment.
  • Oral tetracycline, oxytetracycline, doxycycline, or lymecycline are first-line options. Erythromycin is an alternative if tetracyclines are poorly tolerated or contraindicated (such as in pregnancy). Minocycline is not recommended.
  • Benzoyl peroxide or a topical retinoid are recommended as adjunctive treatment for most people. Azelaic acid is an alternative, but avoid the use of topical antibiotics with oral antibiotics.
  • Consider prescribing a combined oral contraceptive in women who require contraception.