Acne

Acne is a disorder of the oil-producing glands and the hair follicles they empty into. The lining of the follicle sheds cells faster than it clears them, sebum production rises under the influence of hormones, the follicle blocks, and inflammation follows. That sequence produces the whole range of what acne looks like: blackheads and whiteheads where the blockage is the main event, papules and pustules where inflammation is, and nodules and cysts where it goes deep.

It affects the large majority of people at some point, most often from the early teens and usually settling in the twenties, though a substantial number of people — women more than men — have it well into adult life or get it for the first time then.

One correction belongs at the very top, because almost everything that is wrongly recommended for acne follows from getting it wrong. Acne is not an infection. A bacterium, Cutibacterium acnes, lives in follicles and contributes to the inflammation, but it is a normal resident of human skin and acne is not caught, not contagious and not a matter of the skin being dirty or insufficiently washed. This is also why antibiotics are never used on their own for acne: they work in it partly as anti-inflammatories, and used alone they breed resistance without addressing the blockage.

What makes it worse, and what does not

Picking and squeezing. This is the one with the clearest consequence: it raises the risk of permanent scarring, and UK guidance says so explicitly. It is also the hardest advice in the subject to follow.

Washing too much. Scrubbing, exfoliating and washing repeatedly through the day strips the skin barrier and inflames the follicles further. Twice daily is the figure.

Oily and comedogenic products — heavy moisturisers, oil-based sunscreens and make-up, hair oils and pomades that run onto the forehead. Make-up itself is fine; the formulation matters, and so does taking it off at the end of the day. Face oils, coconut oil and olive oil belong in this group rather than in the remedies one.

Sustained friction and occlusion — a chinstrap, a tight collar, a phone held against the jaw, sports equipment. Resting a hand on the face occasionally is not a cause of acne, despite how often it is listed as one.

Diet, honestly. There is observational evidence associating acne with a high glycaemic load and, more weakly, with milk. There is not enough evidence to recommend any specific diet for acne, and current UK guidance says exactly that: eat a balanced diet. Claims that sugar has been proven to cause acne, or that a vegan diet is the answer, go well past what is known — and restrictive diets adopted in the teens, for a condition that is going to be treated with medicines anyway, carry costs of their own. Chocolate's reputation is not supported, and caffeine has no established role at all.

Stress probably aggravates existing acne. It does not cause it, and there is not much to do with the information beyond the general case for managing stress.

Genetics matters a good deal, and is the one factor nobody can act on. It is worth knowing anyway, because it answers the question of why one person doing everything right has worse skin than another doing nothing.

Skin care that helps

Modest and specific. A gentle non-soap facial wash — a synthetic detergent cleanser rather than ordinary soap, which is alkaline and tends to irritate — twice a day. A light, non-comedogenic moisturiser, which matters more once treatment starts, since most acne treatments are drying. A non-comedogenic sunscreen, which matters for the reasons under marks and scars below. No scrubs, no astringents, no steam-and-squeeze routines.

That is the whole of it. Skin care manages the condition's surroundings; it does not treat it.

What actually treats it

Something available without a prescription is a reasonable starting point for mild acne: benzoyl peroxide is the mainstay, and it works — slowly, with some initial dryness and irritation, and with a real tendency to bleach towels and pillowcases. Starting every other day, or washing it off after a short period at first, makes it tolerable. Preparations containing salicylic acid, azelaic acid or niacinamide are also sold over the counter.

Beyond that, UK guidance sets out a clear first line, and the pattern is worth knowing because it is not what most people expect. Treatment is a fixed combination of two active ingredients, applied once daily in the evening for twelve weeks, then reviewed. The combinations used are adapalene with benzoyl peroxide, tretinoin with clindamycin, or benzoyl peroxide with clindamycin.

For moderate to severe acne, a topical treatment is combined with an oral antibiotic — lymecycline or doxycycline once daily — or topical azelaic acid is used alongside one. And there are firm rules around those antibiotics:

• Never an antibiotic alone, topical or oral.
• Never a topical and an oral antibiotic together.
• Courses beyond six months are exceptional, and reviewed every three months.
• At twelve weeks the oral antibiotic stops if the acne has cleared, while the topical treatment continues.

For people who have periods, a combined oral contraceptive is an option alongside topical treatment, and is particularly relevant where there are other signs of excess androgen or a diagnosis of polycystic ovary syndrome.

Isotretinoin taken by mouth is for severe acne that has not responded to proper courses of the above, or acne that is scarring. It is effective and it is a serious drug: a specialist prescribes it, pregnancy must be prevented throughout because it causes severe birth defects, and mental wellbeing is monitored during treatment.

Two expectations worth setting against all of it. Nothing works overnight, and twelve weeks is the standard interval before judging a treatment. And skin often looks worse in the first few weeks of a retinoid before it looks better, which is the point at which most people stop.

The remedies, assessed one at a time

Acne attracts an enormous amount of home treatment, and it is not all of a piece — one of these has better evidence behind it than its reputation suggests, and two of them cause harm.

Tea tree oil is the one with real evidence. A five per cent gel has been tested in small randomised trials, including one directly against five per cent benzoyl peroxide. Both treatments reduced inflamed and non-inflamed lesions; benzoyl peroxide acted faster and somewhat more strongly, and tea tree was better tolerated, with less dryness and stinging. The trials are few, small and old, and none of them looked at scarring. But the honest summary is that a properly made five per cent preparation is a defensible option for mild acne, which cannot be said of anything else on this list.

With two conditions. It is used at that sort of dilution, not neat — and the broader reasons are under using essential oils safely. And tea tree is among the commoner causes of allergic contact dermatitis from essential oils, so a reaction is a reason to stop rather than persist.

Zinc taken by mouth has some weak supporting evidence, though less than benzoyl peroxide and with stomach upset at higher doses. The explanation usually offered for it — that it strengthens the immune system to fight the infection — is wrong twice over, since acne is not an infection.

Green tea brewed and applied to the skin, or drunk: no useful evidence either way.

Egg white masks do nothing, and the claim made for them is anatomically impossible. Pores do not open and close. They are follicle openings with a fixed size, and nothing applied to the surface shuts them.

Aloe vera and honey are harmless and weakly supported — aloe has some evidence as an addition to a topical retinoid rather than instead of one.

Lemon juice applied to the face should not be used, and it is worth being specific about why, because it is recommended constantly for exactly the marks it makes worse. Citrus juice contains furocoumarins, the compounds that make expressed bergamot and lime oil phototoxic. On skin, in daylight, they cause a burn that heals leaving lasting pigmentation. Its acidity damages the skin barrier as well. As a treatment for dark marks it produces the injury it claims to remove.

Neat essential oil left on the skin overnight — lavender is the one usually named — should not be used either. Undiluted essential oil on facial skin for hours risks chemical irritation and sensitisation, and the sensitisation is permanent once established.

Toothpaste and bicarbonate of soda, while on the subject: both are strongly alkaline, both damage the barrier, and neither treats acne.

Marks and scars, which are not the same thing

This distinction is the most useful thing in the article, and almost everything written about getting rid of acne scars ignores it.

Marks are flat and they fade. A red or purple patch left where a spot was is post-inflammatory erythema; a brown or grey one is post-inflammatory hyperpigmentation, which is commoner and more persistent in darker skin. Both are colour changes in otherwise intact skin, and both resolve on their own over months — sometimes many months, which is why they get mistaken for permanent damage. The useful interventions are patience, daily sunscreen, which stops pigmentation deepening, and not picking at the spot that is creating them.

Scars are textural, and they are permanent. Depressed ones come in recognised shapes — narrow and deep, square-edged, or broad and shallow. Raised ones occur more often on the chest, shoulders and back. Nothing applied from a bottle, kitchen or pharmacy, raises or flattens a scar, and anything claiming otherwise is not telling the truth.

The treatment for acne scarring is preventing it, which means treating the acne properly and early, and leaving the spots alone. Where scarring has already happened, the options are procedural rather than topical: laser resurfacing, techniques that lift or excise individual scars, and chemical peels, carried out by a dermatology service. UK guidance is that severe scarring still present a year after the acne has cleared warrants referral to a team with expertise in it.

The important consequence of this is about timing rather than technique. Acne that is scarring is a reason to be seen now, not after another few months of waiting for something to work.

Helping a teenager with it

Severe acne in adolescence is not a cosmetic inconvenience. It is strongly associated with low self-esteem, social withdrawal and depression, and it arrives at the age when appearance carries the most weight it will ever carry.

Most of what helps is unglamorous. Offering help early rather than waiting to be asked, since many teenagers are too embarrassed to raise it and will not. Treating it as a medical matter with a treatment rather than a hygiene failure to be lectured about, which is both kinder and more accurate. Buying something that works rather than whatever is advertised. Being realistic together about the twelve weeks, so that a treatment is not abandoned at week three. And going to a GP rather than persisting with the shelf at the chemist, because the effective combinations are prescription-only and there is nothing to pay for the appointment.

The argument for doing this early rather than eventually is not only about distress. It is that scarring is prevented and not cured.

When to be seen

• Any acne that is scarring, or leaving pigment changes that are not fading — promptly, for the reason above.
• Mild to moderate acne that has not responded to two completed courses of treatment.
• Moderate to severe acne that has not responded to treatment including an oral antibiotic.
• Deep, painful nodules and cysts, rather than surface spots.
• Acne with other signs of hormonal change — irregular periods, unusual hair growth — which may point to an underlying cause worth treating.
• Acne that appeared or worsened after starting a medicine, which may be the medicine.
• Sudden, severe, ulcerating acne with fever and feeling unwell, which is rare and needs same-day assessment.

And the one that UK guidance names outright and that nobody should feel awkward about raising: persistent psychological distress. Significant anxiety or depression about it, or a preoccupation with the appearance of the skin that has taken over, is a legitimate reason for referral in its own right — not something to be earned by having bad enough skin.

See also rosacea, which is frequently mistaken for acne and treated differently, and eczema.