Medical Encyclopaedia › Acne (short definition)
In brief: Acne (acne vulgaris) is a very common disease of the sebaceous gland follicles. It usually begins at puberty and appears mainly on the face, chest and back with blackheads, papules and pustules.
How does acne develop?
Four processes interact: under the influence of androgens, the sebaceous glands produce more sebum, the opening of the hair follicle becomes keratinised and blocked, the bacterium Cutibacterium acnes multiplies in the trapped sebum, and inflammation develops. Hereditary predisposition plays an important role; certain medicines, comedogenic cosmetics and hormonal changes can also promote acne. The influence of diet is debated – there is some evidence above all for very high-sugar diets and dairy products, but the data are not clear-cut.
Types and severity
A distinction is made between comedonal acne with predominantly open and closed comedones (blackheads and whiteheads), papulopustular acne with inflammatory papules and pustules, and severe acne conglobata with deep, painful nodules that can leave scars. Special forms include late-onset acne in adults and drug-induced acne.
Treatment
Treatment depends on severity. For mild forms, topically applied active substances such as benzoyl peroxide, retinoids (e.g. adapalene) or azelaic acid may be considered. In moderate acne, these are often combined with antibiotics, which should only be used for a limited time because of possible resistance. Severe cases are frequently treated with isotretinoin, which has strict contraception requirements because of its risk of birth defects. In women, hormonal approaches can also be useful. Many remedies only work after several weeks; initial skin irritation is common.
Everyday care
Gentle cleansing, non-comedogenic skincare products and not squeezing spots help to prevent inflammation and scarring. Strongly drying or alcohol-based products can irritate the skin further.
When to see a doctor?
In the case of inflammatory nodules, scarring, considerable distress, or if over-the-counter measures bring no improvement after about two to three months, a dermatological assessment is advisable. Acne that suddenly appears in adulthood can also have hormonal causes.
Related terms in the encyclopaedia
Comedones, Sebaceous glands, Benzoyl peroxide, Retinoids, Azelaic acid, Isotretinoin, Rosacea, Scar
Sources
- Deutsche Dermatologische Gesellschaft (DDG): S2k-Leitlinie zur Therapie der Akne, AWMF-Register 013-017
- European Dermatology Forum: European evidence-based (S3) guideline for the treatment of acne
- IQWiG: gesundheitsinformation.de – Gesundheitsinformationen des Instituts für Qualität und Wirtschaftlichkeit im Gesundheitswesen
Note: This article is for general information and does not replace advice, diagnosis or treatment from a doctor or pharmacist. Last updated: October 2026.