Acne vulgaris is the most common skin condition in the UK, affecting an estimated 95% of people between the ages of 11 and 30 at some point in their lives. It ranges from a few occasional blackheads to severe, painful cysts that leave lasting scars. Understanding what acne is — and how it develops — is the first step towards managing it effectively.

What Is Acne?

Acne develops when hair follicles in the skin become blocked by a combination of dead skin cells, excess sebum (the skin’s natural oil), and bacteria — primarily Cutibacterium acnes. When a follicle is blocked, a spot forms. If this happens repeatedly across multiple follicles, the condition is diagnosed as acne vulgaris.

Acne is not caused by dirty skin or poor hygiene. It is driven predominantly by hormonal changes (which is why it peaks during adolescence and can flare during menstrual cycles), genetic predisposition, and the skin’s inflammatory response to bacterial colonisation. According to NHS estimates, acne affects around 80% of teenagers and persists into adulthood in a significant proportion of cases.

What Causes Acne?

Several factors contribute to the development of acne. The most significant are:

• Excess sebum production — driven largely by androgens (male hormones present in both sexes), which enlarge and overstimulate oil glands
• Abnormal skin cell turnover — dead skin cells shed too slowly and accumulate inside follicles, forming plugs
• Bacterial colonisation — C. acnes thrives in blocked follicles, triggering an immune-mediated inflammatory response
• Hormonal fluctuations — puberty, menstrual cycles, polycystic ovary syndrome (PCOS), and pregnancy can all worsen acne
• Certain medications — including corticosteroids, lithium, and some anticonvulsants
• Diet — emerging evidence suggests high-glycaemic foods and dairy may worsen acne in susceptible individuals

Types and Symptoms of Acne

Acne can appear on the face, chest, back, shoulders, and upper arms — wherever sebaceous glands are densest. Spots are classified into two broad categories:

• Non-inflammatory (comedones): blackheads (open pores filled with oxidised sebum) and whiteheads (closed, flesh-coloured bumps)
• Inflammatory lesions: papules (small red bumps), pustules (pus-filled spots), nodules (deep, painful lumps), and cysts (large, fluctuant lesions that frequently scar)

Severity is graded as mild (mostly comedones, few inflammatory lesions), moderate (mixed comedones and inflammatory spots, more widespread), or severe (extensive papules, nodules, cysts, with a high risk of scarring).

Medical Treatments for Acne

NICE guidelines recommend a stepwise approach to acne treatment. The right treatment depends on the type and severity of your acne. Most regimens take 6–12 weeks to show meaningful improvement — consistency is essential.

Topical Treatments

Oral (Systemic) Treatments

• Oral antibiotics (doxycycline, lymecycline) — for moderate-to-severe inflammatory acne; used for 3–6 months alongside a topical agent to reduce resistance risk
• Combined oral contraceptive pill — for women with hormonally-driven acne; co-cyprindiol (Dianette) is specifically licensed for acne
• Isotretinoin (Roaccutane) — for severe or scarring acne; highly effective, requires specialist monitoring including blood tests and strict pregnancy prevention

Acne Prevention: Practical Tips

• Wash your face twice daily with a gentle, non-comedogenic cleanser (avoid harsh scrubbing)
• Use oil-free, non-comedogenic moisturisers and cosmetics
• Remove all make-up before sleeping
• Avoid touching or picking spots — this worsens inflammation and increases scarring risk
• Shower promptly after exercise to remove sweat and oil
• Manage stress where possible — elevated cortisol can increase sebum production
• Consider reducing high-glycaemic foods and dairy if you notice dietary triggers