Acne is a chronic inflammatory skin condition that develops when hair follicles become blocked with excess oil (sebum), dead skin cells and bacteria. It affects people of all ages but is most prevalent during adolescence and early adulthood.
Acne, also known as acne vulgaris, occurs when the sebaceous glands attached to hair follicles become overactive. These glands produce sebum, an oily substance that helps protect the skin. When too much sebum is produced, it can combine with dead skin cells to block the follicle opening.
Within these blocked pores, naturally occurring skin bacteria (Cutibacterium acnes) can multiply. This process triggers inflammation, leading to the formation of visible acne lesions such as blackheads, pimples and deeper, painful lumps.
Most people experience acne at some point. It is especially common during adolescence due to hormonal changes, but many adults continue to have acne into their 20s, 30s and beyond. Adult acne is more common in women and often linked to hormonal fluctuations. Mild acne-like spots, often referred to as baby acne, can also occur in newborns and infants, but this form usually resolves on its own and is different from adolescent or adult acne.
Acne is one of the most common skin conditions in the UK and worldwide. The vast majority of teenagers experience acne at some stage, and many adults continue to have breakouts beyond their teen years. Around 85% of people aged 12–24 have acne to some degree, and a notable number of adults also experience ongoing spots past their twenties.
Genetics plays a significant role in acne susceptibility. Having a family history of acne increases the likelihood of developing the condition, suggesting inherited differences in sebum production and skin response.
Acne typically appears in areas with more oil glands — most often on the face, chest, upper back and shoulders. These are the parts of the skin most prone to clogged follicles and inflammation.
During adolescence, acne can be more severe in males. In adulthood, acne is frequently reported in women, often associated with hormonal changes such as menstrual cycles, pregnancy or menopause.
Acne can present as different lesion types, including:
When acne mainly consists of blackheads and whiteheads, it is referred to as comedonal acne. When inflammation is present, including papules and pustules, it is described as inflammatory acne. More severe forms include nodular acne and cystic acne, both of which develop deeper within the skin and are more likely to result in permanent scarring if not treated appropriately.
Hormonal acne commonly affects the lower face, jawline and chin and may flare in response to hormonal fluctuations. All forms of acne develop from blocked pores, but inflammatory and deeper lesions carry a greater risk of pain, pigmentation changes and scarring if left untreated.
Note: Some conditions, such as fungal acne (Malassezia folliculitis), can resemble acne but are caused by yeast rather than blocked pores and require a different treatment approach.
Common acne symptoms include:
Severity varies from occasional mild spots to widespread, inflamed lesions that can be painful and long-lasting.
Acne occurs when hair follicles become clogged with excess oil, dead skin cells and bacteria. Hormonal changes, particularly increased androgen levels, stimulate oil production and worsen blockage and inflammation. Genetics also influence susceptibility.
Stress does not directly cause acne, but it can aggravate existing acne by increasing inflammation and hormonal activity that stimulates oil production.
Hormones, especially androgens such as testosterone, increase sebum production and are a key factor in acne development. Hormonal fluctuations during puberty, menstruation and pregnancy are common triggers.
Common triggers and risk factors that can worsen acne include:
There is no strong evidence that poor hygiene causes acne; excessive washing may irritate the skin and make symptoms worse. While diet (e.g. high glycaemic foods or dairy) has been linked to acne in some studies, the evidence is not definitive and varies between individuals.
Acne is diagnosed clinically by a GP or dermatologist based on the appearance, number and type of lesions. A clinician may also ask about onset, triggers, sleep, diet and medication history. Hormonal tests may be considered if acne appears suddenly in adulthood or alongside other symptoms like irregular periods.
Acne is typically a common skin issue. However, when acne starts suddenly in adulthood or occurs alongside irregular periods or excess hair growth, underlying hormonal conditions such as polycystic ovary syndrome (PCOS) may be considered.
You should seek medical advice if:
A dermatologist can offer specialist care and advanced acne treatments.
Treatment depends on acne severity and individual factors. It aims to reduce sebum production, prevent blocked pores, limit bacterial growth and control inflammation. Many treatments take several weeks to months to show benefit.
Treatment choice depends on severity, skin type and individual response.
Yes. Acne can recur, especially if underlying triggers such as hormonal fluctuations persist. Maintenance treatment may help keep acne under control long-term.
Acne often improves with age, especially as hormone levels stabilise, but it can persist into adulthood for some people. Inflammatory acne, particularly cysts and nodules, has a higher risk of permanent acne scarring, especially if spots are picked or squeezed. Persistent acne may affect mental wellbeing, particularly when it is long-lasting or severe.
Yes. Acne can cause permanent scarring, particularly when inflammatory lesions (nodules and cysts) damage deeper skin layers. Picking or squeezing spots increases scar risk. Early, effective treatment reduces this risk.
While acne cannot always be prevented, flare-ups may be reduced by:
Lifestyle habits such as managing stress and maintaining a balanced diet may also support overall skin health.
See a GP or dermatologist if:
Early assessment can help guide appropriate treatment and reduce the risk of complications such as scarring.
If acne does not improve with over-the-counter treatments or is leaving marks or scars, professional treatment can help. Take a free online acne assessment with Aventus Clinic today for personalised guidance and support.
