• The diagnosis is based on the patient's history and clinical presentation.
  • Treatment is chosen according to the subtype of the patient’s acne.
  • The treatment response requires time and the patient should be motivated towards a long term therapy.
  • The condition may cause cosmetic problems and it may have an impact on psychosocial health.

Epidemiology and aetiology

  • A common skin disease, with lifetime prevalence of 60–80%
  • 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 with a fluctuating clinical course
  • Usually most prevalent on the face, upper back and chest.
  • May leave disfiguring scars and cause psychosocial problems.
  • Scar formation is individual; more common in severe acne.
  • Divided into subtypes, which may co-exist.
    • Comedonal acne (acne comedonica; 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.
    • Other variants of severe cystic acne
      • 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 often accompanied by fever as well as joint and muscular pains.


  • 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 (glucocorticoids, 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 usually 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 subtype of the patient’s acne.
  • Medicinal ointment is usually applied in the evening to all areas where acne has occurred.
  • 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, as required, continued long term, for example twice a week (using a medicinal ointment suitable for maintenance therapy, see below).
  • Medicinal ointments 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 and benzoyl peroxide gel 0.1% or stronger 0.3%
      • 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).
  • Maintenance therapy
    • Once the skin is in better condition, the treatment is continued, as required, with a medicinal ointment suitable for maintenance therapy (not containing antimicrobials).
      • Adapalene gel
      • Tretinoin (Vitamin A) cream 0.025% or 0.05%
      • Azelaic acid cream 20% or gel 15%
      • Benzoyl peroxide gel or wash gel 5%
      • Adapalene and benzoyl peroxide gel 0.1% or 0.3%

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.
  • 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).
  • Systemic treatment is carried out with doxycycline 50–100 mg once daily, lymecycline 150–300 mg once or twice daily, or tetracycline 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 breastfeeding.
    • If tetracyclines cannot be used, drugs of the macrolide group have been used (evidence is scarce in the treatment of acne): for example erythromycin 250–500 mg twice daily, azithromycin 500 mg once daily (3-day course that is repeated once or twice in a month), roxithromycin 150–300 mg once daily.
  • It is advisable to continue with systemic treatment until the acne has clearly settled down; this usually takes 1 to 3 months. The daily dose may be reduced when the acne has settled down.
  • 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.
  • Photo and laser therapies
    • There is no strong evidence on the efficacy of photo therapies (e.g. PDT, blue light, infrared) and laser therapies in acne, but they may be beneficial to some patients as additional therapy[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 glucocorticoid 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)
  • In severe acne with a significant number of inflammatory lesions leading to scarring, isotretinoin therapy is used, guided 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
    • 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 (two methods, e.g. oral contraceptives or an IUD and a condom).
    • Before treatment is started the following laboratory parameters should be checked, this can be done by the referring physician in primary care: ALT, cholesterol, triglycerides and, in women, additionally the serum level of human chorionic gonadotropin (qualitative).
      • 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
    • Acne that starts at a very young age may need the involvement of an paediatrician or a paediatric endocrinologist.


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