Acne
Symptoms, Causes & Treatment
Understanding acne: what causes it, why some cases are severe, and the prescription treatments that clear skin when over-the-counter products have failed.
What Is Acne?
Acne (acne vulgaris) is a common inflammatory skin condition that occurs when hair follicles become blocked with dead skin cells and sebum (oil), creating an environment in which bacteria multiply and trigger inflammation. It most commonly affects the face, back, chest, and shoulders -- areas with the highest concentration of sebaceous (oil-producing) glands.
Acne is the most common skin condition in the UK, affecting up to 95% of people aged 11–30 to some degree. While it is most prevalent during adolescence, acne increasingly persists into adulthood -- approximately 3% of adults over 35 have acne, and adult-onset acne (particularly in women) is becoming more widely recognised.
Acne ranges from mild (a few blackheads and whiteheads) to severe (deep, painful cysts and nodules that can cause permanent scarring). The physical impact is compounded by a significant psychological burden: acne is strongly associated with reduced self-esteem, social anxiety, depression, and impaired quality of life.
Effective treatments are available for all types and severities of acne, and early treatment reduces the risk of permanent scarring.
What Are the Symptoms of Acne?
Acne presents on a spectrum from mild to severe. Understanding the type of lesions helps determine the appropriate treatment.
Comedones (blackheads, whiteheads) · Papules (red, tender bumps) · Pustules (pimples with pus) · Nodules (large, painful, solid lumps) · Cysts (painful, pus-filled — risk of scarring) · Oily skin · Scarring after severe lesions
Severe cystic acne unresponsive to antibiotics · Acne fulminans (sudden severe acne with systemic fever — rare emergency) · Acne with virilisation signs in women (suggesting PCOS or androgen excess) · Significant psychological distress, depression, or self-harm related to acne
Seek urgent review if acne is causing severe psychological distress, if nodulo-cystic acne is causing large painful cysts, or if acne appears alongside signs of hormonal disorder.
What Causes Acne?
Acne results from four interacting factors: excess sebum production, follicular hyperkeratinisation, C. acnes bacterial proliferation, and inflammation.
Acne vulgaris is caused by four interacting factors: excess sebum production, Cutibacterium acnes (formerly P. acnes) overgrowth, follicular hyperkeratinisation, and inflammation.
Androgen excess — from puberty, PCOS, or androgen-secreting tumours — stimulates sebaceous glands, producing excess sebum and promoting acne formation. This explains why the combined pill improves acne in many women.
Isotretinoin (Roaccutane) is the most effective acne treatment available. It reduces sebum by 90%, normalises follicular keratinisation, and reduces C. acnes colonisation. It is teratogenic and requires strict monitoring.
Multiple psoriasis triggers are recognised: streptococcal throat infection (especially guttate psoriasis), medications (lithium, beta-blockers, antimalarials, NSAIDs), stress, trauma (Koebner phenomenon), alcohol, and smoking.
Around 30% of people with skin psoriasis develop psoriatic arthritis — an inflammatory arthropathy with joint erosions, enthesitis, and dactylitis. It can be severe and requires DMARD treatment to prevent joint destruction.
Psoriasis is an immune-mediated chronic inflammatory skin disease. T-cell activation drives rapid keratinocyte proliferation (3–5 days instead of 28–30), producing the characteristic thickened plaques.
Key Risk Factors
How Is Acne Assessed?
Acne is diagnosed clinically. Assessment includes grading severity, identifying lesion types, reviewing previous treatments, and checking for hormonal causes in women.
How Is Acne Treated?
Treatment is matched to severity. Combination therapy is consistently more effective than monotherapy.
Supportive Measures
Use a gentle, non-comedogenic cleanser twice daily. Avoid scrubbing. Use oil-free moisturiser and sunscreen. Do not pick or squeeze spots. Give treatments 8–12 weeks before judging effectiveness.
Persistent or Returning Acne
Acne commonly recurs after stopping oral antibiotics or isotretinoin. Maintenance topical therapy (retinoid ± benzoyl peroxide) is recommended after completing antibiotic courses. Women with hormonal acne may benefit from ongoing combined oral contraceptive use.
When Should You Seek Medical Advice for Acne?
Acne is causing severe psychological distress or suicidal ideation · Large painful cysts are developing rapidly.
Over-the-counter treatments have not worked after 2 months · Acne is leaving scars · You want to discuss prescription options including isotretinoin · Acne is significantly affecting your confidence.
How Can You Manage Acne Long Term?
Acne management is long-term. These strategies help maintain clear skin between and after treatment courses.
Start with gentle, consistent moisturising before escalating to active treatments. Over-the-counter benzoyl peroxide (2.5–5%) and adapalene 0.1% (Differin) are effective for mild acne without a prescription.
Apply emollient to slightly damp skin immediately after bathing (within 3 minutes) to lock in moisture. Use at least 250–500g per week. Emollients are the most important eczema management tool — more important than any topical steroid.
Identify and avoid personal eczema triggers: dust mites, pet dander, pollen, food allergens, synthetic fabrics, perfumed products, and stress. Keep a symptom diary to identify patterns.
Wet wrapping in a flare (applying emollient-soaked bandages over affected areas) provides rapid relief and significantly reduces itch. It can be done at home after brief instruction from a nurse or dermatologist.
Frequent, effective milk removal is the most important mastitis prevention. Feed or express every 2–3 hours; never skip feeds. Get breastfeeding support from a midwife, health visitor, or lactation consultant early — before problems develop.
Ensure your baby latches on deeply and correctly. A poor latch causes nipple trauma (cracks), which are an entry point for bacteria. Ask for a latch assessment if breastfeeding is painful.
Speak to a Clinician About Acne
Through The GP Service, a licensed clinician can assess your acne, prescribe topical retinoids, antibiotics, or hormonal treatments, and refer for isotretinoin where appropriate.
Expert clinical advice, when you need it.
Acne FAQs
Adult acne is caused by the same mechanism as teenage acne — excess sebum, P. acnes bacteria, and follicular blockage — but is often driven by hormonal fluctuations, stress, certain medications, or skincare products rather than puberty.
Evidence suggests high-glycaemic-index foods and dairy may worsen acne in susceptible individuals. A low-GI diet rich in vegetables and whole grains may modestly improve acne, though dietary intervention alone is rarely sufficient for moderate-to-severe acne.
Oral antibiotics for acne are typically used for 3–6 months, then stopped to minimise antibiotic resistance. They are safe at standard acne doses for this duration. Long-term use beyond 6 months is generally avoided.
Yes. Combined oral contraceptives containing anti-androgenic progestogens (such as co-cyprindiol/Dianette) are effective for hormonal acne in women. They are typically prescribed after topical treatments have not achieved adequate control.
Most acne treatments take 6–12 weeks to show meaningful improvement. It is important to persist with treatment and not switch agents prematurely. Isotretinoin typically requires a 4–6 month course.
Post-inflammatory hyperpigmentation (flat dark marks) usually fades over months. True acne scars (pitted or raised) do not resolve without treatment. Dermatology referral for laser, microneedling, or chemical peels may be appropriate.
Isotretinoin is highly effective and can achieve long-term remission. It requires careful monitoring due to teratogenicity (must not be used in pregnancy), liver effects, and mood changes. It is prescribed under specialist supervision with mandatory contraception in women.
Yes. GPs can prescribe topical retinoids, antibiotics, and hormonal treatments for acne. Isotretinoin requires dermatologist initiation. An online GP consultation is an effective way to start or review acne treatment.