• The diagnosis is based on the patient's history and clinical presentation.
  • Treatment is chosen according to the patient’s acne lesions and skin type.
  • Topical treatment plays an important role.
  • Maintenance therapy prevents exacerbations.
  • The condition causes cosmetic problems and has an impact on psychosocial health.
  • The patient should be motivated towards a long term therapy.

Epidemiology and aetiology

  • A common skin disease, which affects 60–80% of the Caucasian population
  • In puberty acne is more common in males and in adulthood in females; acne may first manifest itself in adulthood
  • Endogeneous and multifactorial
  • Hereditary tendency; in a great majority of cases the disease can be encountered in close family members.

Clinical picture

  • A chronic skin disease associated with periodic exacerbations
  • Usually most prevalent on the face, upper back and chest.
  • May leave disfiguring scars and cause psychosocial problems.
  • Scar formation is individual and is not always linked to the severity of the disease.
  • Divided into subtypes, which often co-exists in the same patient.
    • Comedonal acne (acne comedonicus; pictures (Acne in a small child) (Comedones in acne) (Comedones in the cheek))
      • The main skin changes encompass both open and closed comedones. Only slight inflammatory changes on the skin.
    • Common acne (acne vulgaris), also known as papulopustular acne (pictures (Acne) (Acne vulgaris) (Papulopustular acne on the face))
      • Lesions are mainly red papules and pustules, but also comedones occur.
    • Cystic acne (acne cystica; pictures (An acne cyst at the base of the nose) (Cystic acne in a young man) (Cystic acne) (Cystic acne on the back) (Cystic acne on the chest))
      • Deep burrowing lesions, often painful and sore, can be seen on the skin, in addition to comedones, papules and pustules.
    • There are several severe and unusual variants of acne, and their treatment belongs to a dermatologist.
      • Acne conglobata is the chronic form of cystic acne, and it is associated with purulent and ulcerative inflammatory changes. In addition to the sites of predilection for common acne lesions, acne conglobata can also appear on the buttocks and flexural areas. Double comedones are typical; one sebaceous gland duct opens onto the skin via two orifices.
      • Acne fulminans is a rare disease, almost exclusively seen in young adolescent boys, characterised by severely inflamed and ulcerative acne lesions accompanied by fever, joint and muscular pains and sometimes also bone changes similar to those in osteomyelitis.
      • Acne inversa (hidradenitis suppurativa) is a chronic and difficult to treat ulcerative inflammation of the apocrine sweat glands most commonly seen in an adult patient’s flexural areas, underarms and the groin. Scarring occurs as the condition heals.


  • Diagnosis is clinical.
  • Acne can be diagnosed by the presence of comedones (blackheads = open comedones, whiteheads = closed comedones; picture (Comedones in acne)).
  • The patient should be asked about factors that aggravate acne.
    • External factors (hygiene products and cosmetics including oily lotions, mechanical occlusion, rubbing, hot environment in some cases, sweaty work, holidays and sun exposure)
    • Internal factors (corticosteroids, lithium, iodine, antiepileptic medication, testosterone, anabolic streroids)
    • Rare diseases causing hyperandrogenism (polycystic ovarian syndrome [PCOS] (Polycystic ovary syndrome (PCOS)); congenital adrenal hyperplasia, non-classic form)


  • In the absence of other signs of hyperandrogenism (hirsutism, abnormal menstrual bleeding, infertility) no hormone testing is required.
  • Acne starting at a very young age might be a sign of an endocrine disease.
    • If hyperandrogenism is strongly suspected, the serum levels of free testosterone may be tested in a female patient.

Differential diagnosis

  • Rosacea (Rosacea): pustules, mainly affects the central portion of the face, telangiectasias, flush reaction
  • Perioral dermatitis (Perioral dermatitis): often around the mouth, only papules
  • Folliculitis (Skin abscess and folliculitis): single pustules around the beard area or more widespread pustules on the upper body
  • Acneiform drug reactions and rare rashes that resemble acne

Topical treatment

  • Skin lesions are slow to heal. The topical treatment of the skin takes time, and the treating doctor must be able to motivate the patient to the treatment.
  • The skin is washed in the morning and evening with water and soap or with an antibacterial wash solution.
  • Treatment is chosen according to the patient’s acne lesions and skin type.
  • The use of the skincare product must be explained to the patient in detail.
  • The skincare product is usually applied in the evening to all areas where acne has occurred, not only on the spots present at the moment.
  • The efficacy of treatment does not often become apparent until after several weeks, and the patient often abandons the treatment too early as inefficient.
  • Topical treatment should be continued until the skin condition has subsided; the treatment is then continued long term, for example twice a week (maintenance therapy).
  • Prophylactic topical treatment has been shown to reduce exacerbations.
  • Skincare products may cause skin dryness and redness particularly at the early stages of the treatment. Should this occur, the product should be applied more infrequently, the treatment should be stopped for a while or another topical product tried.
  • To reduce irritation a basic topical ointment with high water content may be applied over the medicinal ointment after a few minutes; the irritation usually subsides as the skin becomes accustomed to the topical skincare product.
  • Treatment may be started with a lower concentration and/or the patient may be advised to wash the medicine off the skin after a few hours in the early phase (for 2–3 weeks).
  • Comedonal acne
    • Adapalene gel
    • Tretinoin (Vitamin A acid) 0.025% and 0.05% cream
    • Azelaic acid 20% cream or 15% gel
    • Benzoyl peroxide gel or wash 5%.
    • Topical antimicrobial treatment is not recommended in comedonal acne.
  • Acne vulgaris
    • Treatment is started with a combination gel
      • Adapalene gel and benzoyl peroxide
      • Benzoyl peroxide and clindamycin
      • Tretinoin and clindamycin
    • Other topical skincare products used in comedonal acne are also effective.
    • Individual papulopustules can also be intermittently treated with topical antimicrobials in the form of solution, gel or cream (for example clindamycin solution).

Evidence Summaries

Systemic treatment

  • Indicated in widespread or severe acne vulgaris, or when correctly applied topical therapy alone has not proved sufficient.
  • May also be started in milder cases if the patient, for example, is concerned about acne induced scarring. Systemic antimicrobials are not effective in comedonal acne.
  • Topical treatment must continue during systemic treatment. Antimicrobial therapy alone, either systemic or topical, is not recommended in the treatment of acne; it should always be combined with topical treatment with either vitamin A (adapalene or tretinoin), benzoyl peroxide or azelaic acid, or a combination gel (adapalene and benzoyl peroxide, benzoyl peroxide and clindamycin, or tretinoin and clindamycin).
  • Drugs used in systemic treatment include
    • as the first choice, doxycycline 50–100 mg once daily or lymecycline 150–300 mg once or twice daily
    • as an alternative, tetracycline 250–500 mg once or twice daily or erythromycin 250–500 mg once or twice daily.
      • Tetracyclines (particularly doxycycline and tetracycline) may sensitise the patient to sunlight.
      • Tetracyclines should not be given to children younger than 8 years, nor during pregnancy or lactation.
  • It is advisable to continue with systemic treatment until the acne has clearly settled down; this usually takes 2 to 3 months. In some cases the treatment can be prolonged up to 3 to 6 months. Longer treatments are not recommended. The daily dose may be reduced after 1 to 2 months if adverse effects emerge.
  • Except in exceptional cases, the monitoring of laboratory parameters during the treatment is not necessary.

Evidence Summaries

Other treatment

  • Hormonal therapy in women
    • Where contraception is required, the antiandrogenic properties of combined oral contraceptives can be exploited (cyproterone acetate, drospirenone or desogestrel and oestrogen) [Evidence Level: A].
    • Low dose oral progestogen only contraceptives with no androgenic properties are also suitable in acne.
  • Phototherapy
    • In special cases, additional therapies may be used to enhance the treatment, for instance SUP therapy during the dark winter months. It may be possible for a general practitioner to prescribe such treatment. The treatment is long and consists of a course of 15–20 regular sessions, carried out 3 times a week, and requires a well motivated patient [Evidence Level: D].
  • Acne scarring
    • Treatment of acne scars with laser or dermabrasion should not be considered until the active disease has become totally quiescent. An attempt may be made to flatten prominent keloid scars with corticosteroid injections or cryotherapy [Evidence Level: D].
  • Collaboration with a cosmetician (beautician)
    • Correctly carried out deep skin cleansing by a cosmetician is often of benefit in the treatment of comedonal acne. A cosmetician will also give information about the correct make-up to use and skin cleansing.
  • There is no evidence on special diets (e.g. with low glycaemic index), herbal medicines, vitamins, trace elements or CAM treatments (e.g. acupuncture) in the treatment of acne [Evidence Level: D].

Specialist consultation

  • A dermatologist should be consulted in severe forms of acne (acne cystica, conglobata, fulminans, inversa)
  • Acne that starts at a very young age may need the involvement of an endocrinologist.
  • In severe acne with a significant number of inflammatory lesions leading to scarring, the first line treatment is isotretinoin therapy, which can only be prescribed by a dermatologist.
    • Can also be started if the patient fails to respond to all other, properly carried out, treatment options or if acne recurs after 2–3 adequately long courses of correctly dosed antimicrobials combined with topical treatment
    • Isotretinoin is sometimes also used in milder cases, if the patient is concerned about scarring.
    • Teratogenicity is a particular problem. Women of childbearing age must use effective contraception for at least one month before starting treatment and for one month after the end of treatment (oral contraceptives or an IUD).
    • Before treatment is started the following laboratory parameters should be checked, this can be done by the referring physician in primary care: the serum level of human chorionic gonadotropin (qualitative), plasma ALT, cholesterol, triglycerides.
      • A negative pregnancy test must always be obtained before treatment and 5 weeks after the end of treatment, also during the treatment if considered necessary. The dates and results of the laboratory monitoring must be documented.
      • Liver enzymes and lipid values must be checked before the treatment is started, after the first treatment month, and thereafter regularly every 3 months during treatment, unless more frequent testing is warranted.
        • Isotretinoin treatment has been associated with increased plasma triglyceride levels.


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6. Dréno B, Kaufmann R, Talarico S et al. Combination therapy with adapalene-benzoyl peroxide and oral lymecycline in the treatment of moderate to severe acne vulgaris: a multicentre, randomized, double-blind controlled study. Br J Dermatol 2011;165(2):383-90.  [PMID:21495995]

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