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Acne vulgaris

Also known as: acne, spots, breakouts, acne vulgaris

Acne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit, involving follicular hyperkeratinisation, sebum production, Cutibacterium acnes and innate immune activation. It presents as comedones, papules, pustules, nodules or cysts, most often on the face, chest and back.

Evidence status

Strong

Acne has a current NICE guideline with network meta-analyses behind its treatment recommendations — the strongest evidence position of any entry in Skinipedia, though it is the guideline for England and is available rather than mandatory in Wales, with separate arrangements in Northern Ireland and Scotland. What is NOT strongly evidenced is the aesthetic side: NICE recommends exactly one physical treatment for acne, and the peel literature is very low to moderate quality. Note what that means and does not mean — NICE's stated reason is that the evidence was very limited, which is a statement about certainty rather than a finding that the treatments do not work.

What it is#

Acne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit. It presents as comedones, papules, pustules, nodules or cysts, most often on the face, chest and back.

It is also the one condition in Skinipedia with a current national guideline behind it — NICE NG198, with network meta-analyses under its treatment recommendations. So this entry does something the others cannot: it tells you exactly where a skincare professional stands relative to a national standard of care.

Which nation, though. NG198 is the guideline for England. The Welsh Government has an agreement that all NICE guidelines are available to use in Wales, but — except for technology appraisals — their use is not mandatory. In Northern Ireland, NICE guidance is reviewed locally for applicability and endorsed by the Department only where it is found to apply.[7, 8]Scotland has its own arrangements. If you practise outside England, check the pathway that actually applies to you before quoting NG198 as “the” standard.

What actually drives it#

Four processes, running together rather than in sequence:

  • Follicular hyperkeratinisation — the follicular lining fails to shed normally, forming the microcomedone.
  • Sebum production — androgen-driven, and altered in composition as well as quantity.
  • Cutibacterium acnes — a commensal, in a changed follicular environment.
  • Innate immune activation — the inflammation that turns a blocked follicle into a lesion.

The fourth is where the field has moved most, and where practitioner teaching has moved least.

The bacteria question#

Almost every practitioner has been taught that acne is bacterial overgrowth. The evidence does not support that as stated.

One review puts it directly: “proliferation of P. acnes is not the trigger of acne as patients with acne do not harbour more P. acnes in follicles than normal individuals” — the proposed driver being loss of skin microbial diversity together with activation of innate immunity.[2]

Where that needs qualifying

Total follicular carriage and lesion-site abundance are different measurements, and it is worth not flattening one into the other.

Researchers sampled 10 adolescents with severe acne and 10 controls, and found significantly lower alpha diversity in inflammatory lesions than in non-inflammatory lesions or healthy skin — with the species-level difference driven by overabundance of C. acnes at the inflamed site, and phylotype IA1 more represented in acne patients.[3]

And phylotype appears to matter more than count. IA1 isolates showed more efficient early adhesion, greater biomass production, and significantly increased antibiotic tolerance than other phylotypes.[3]

Read the second paragraph carefully, because we did not the first time. The adhesion, biomass and antibiotic-tolerance results are laboratory work on isolates cultured from that skin — the antibiotic experiment used ten lesional IA1 strains in vitro. A twenty-person sampling study does not make every downstream culture experiment a clinical measurement in those twenty people.

The honest synthesis: acne is not a person having too many bacteria. It is a follicle whose environment has shifted, losing diversity and selecting for more virulent strains, in skin whose innate immune system is responding. Which is why “antibacterial” as a product positioning is a poor description of what helps.

Grading it the way NICE does#

Useful because it is numerical, so two practitioners can agree — and because it is the threshold that determines what happens next.

  • Mild to moderate— any number of comedones, up to 34 inflammatory lesions, or up to two nodules.
  • Moderate to severe— 35 or more inflammatory lesions, or three or more nodules.[1]

Counting to 35 in a consultation is not realistic, and it is not the point. The point is that “a few nodules” is a different category from a face full of papules, and it is the category that changes the pathway.

What NICE recommends#

A short version of a long guideline, focused on the parts a non-prescriber needs to recognise.

  • A 12-week course of one first-line option, with the explanation that positive effects can take six to eight weeks to become noticeable. Topical benzoyl peroxide and retinoids are started alternate-day or short-contact to reduce irritation.[1]
  • No antibiotic monotherapy. NICE says explicitly not to use a topical antibiotic alone, an oral antibiotic alone, or the two together — and to continue any antibiotic-containing option beyond six months only in exceptional circumstances, reviewing three-monthly.[1]
  • Diet: the recommendation is a single line — advise people that there is not enough evidence to support specific diets for treating acne.[1]

That last one deserves emphasis, because dietary advice is one of the commonest things offered in a skincare consultation. The national guideline’s position is that the evidence is not there. Saying so is more useful to a client than a dairy elimination they will abandon in three weeks.

The physical-treatments problem#

This is the part of the entry that matters most.

NG198 has a section headed “Physical treatments”. It contains one recommendation:

“Consider photodynamic therapy for people aged 18 and over with moderate to severe acne if other treatments are ineffective, not tolerated or contraindicated.”[1]

That is the whole section. No chemical peels for active acne. No LED. No microneedling. No extraction. No microdermabrasion.

But be precise about what that means

Not recommended is not the same as refuted, and this page said otherwise until August 2026. NICE’s own rationale is that “the evidence for physical treatments for mild to moderate acne was very limited”, and that because of the limited evidence, the committee decided to prioritise a research recommendation on the effectiveness of physical treatments.[1] A research recommendation is an evidence gap. It is a statement about how certain the committee could be, not a finding that these treatments do nothing.

That distinction cuts both ways, and it should. You cannot say “NICE recommends this”. You also cannot say “NICE found it doesn’t work”.

The peel literature says something more specific

A 2018 systematic review found 12 small, heterogeneous randomised trials involving 387 participants, at very low to moderatemethodological quality and too varied to pool. Common peels appeared similarly effective for mild-to-moderate acne and were well tolerated — but two comparisons did separate: glycolic acid beat placebo, and combined salicylic and mandelic acid beat glycolic acid. The authors’ conclusion is that a robust conclusion cannot be drawn about any definitive superiority or equality among current peels.[4]

“No established winner” and “they are all the same” are different claims, and this entry made the second one until it was corrected. The underpowered literature does not support it, and it is the claim that quietly justifies selling whichever peel you happen to stock.

“Probably helps a bit, no idea which one is best, evidence weak” is a defensible thing to say to a client. “This peel clears acne” is not.

Where a skincare professional stands#

The reading of the above that we would push back on is “therefore we have no role”. That is not what the guideline says either.

Three things a skincare professional legitimately owns:

  1. The skin care advice. Recommendations 1.2.1 to 1.2.4 are, almost word for word, a description of a skincare consultation — and they are the part of the pathway a GP has seven minutes to cover.
  2. Recognition and referral. You see faces at length, repeatedly, in good light. Spotting nodulo-cystic acne, scarring beginning, or a client whose acne is destroying their week is real clinical value.
  3. The post-acne work. Pigmentation and scarring, in their proper pathways — which is where the aesthetic modalities actually have evidence.

What is not in scope is presenting a facial as acne treatment while a client’s nodulo-cystic acne scars for another eighteen months. The risk of scarring rises with the severity and the duration of acne[1] — so a course of treatments that delays referral is not neutral. It has a cost, and the client pays it in scars.

The skin care advice#

NICE’s version, which is worth quoting to clients as such:

  • A non-alkaline — pH-neutral or slightly acidic — synthetic detergent (syndet) cleansing product, twice daily on acne-prone skin.
  • Avoid oil-based and comedogenic skincare and sunscreens.
  • Avoid oil-based and comedogenic make-up, and remove make-up at the end of the day.
  • Persistent picking or scratching increases the risk of scarring.[1]

Four lines. No twelve-step routine, no acid rotation, no double-cleansing protocol. When a client asks what they should be doing at home, this is the nationally recommended answer, and you can say where it comes from.

When to refer#

Same day

Acne fulminans — a very severe form of acne conglobata with systemic symptoms — is an urgent same-day referral to the on-call hospital dermatology team, for assessment within 24 hours.[1]

Refer

Diagnostic uncertainty, acne conglobata, or nodulo-cystic acne — to a consultant dermatologist-led team or an accredited GPwER working within a dermatologist-agreed pathway.[1]

Consider referral

Mild-to-moderate acne that has not responded to two completed courses; moderate-to-severe that has not responded to a course containing an oral antibiotic; acne leading to scarring; or acne with persistent pigmentary changes.

And — separately from all of the above — acne of any severity that is causing or contributing to persistent psychological distress or a mental health disorder.[1]

Severity of disease and severity of impact are treated as separate questions in the guideline, and they should be in your consultation too. Mild acne can be devastating.

Scarring#

NICE’s scarring pathway is specific, and it is stricter than the aesthetics market behaves.

If acne-related scarring is severe and persists a year after the acne has cleared, refer to a consultant dermatologist-led team with expertise in scarring management — and in that setting, consider CO2 laser treatment, alone or after punch elevation, or a glycolic acid peel.[1]

Be clear what the one-year point is. It is a service-pathway threshold, and NICE gives two reasons for it — that in the committee’s experience tissue remodelling and healing continue for up to about a year after the acne clears, and that the evidence was not strong enough to recommend referral for everyone with scarring, which would also have significant resource implications.[1] Both are honest reasons. Neither is a biological law saying no scar can be helped before twelve months.

And NICE names three options — glycolic acid peel, CO2 laser alone, or CO2laser after punch elevation — on the basis that they “showed some efficacy”, in a dermatologist-led setting, with the committee prioritising further research on the remaining uncertainty. That is not the same as calling them the best-evidenced treatments available.

The wider evidence supports the caution. Cochrane, across 24 trials and 789 adults, found a lack of high-quality evidence throughout acne scar treatment, and on needling specifically no comparison rose above low-quality evidence.[5]

Clients on isotretinoin#

For procedures, the 2017 ASDS consensus found insufficient evidence to justify delaying superficial chemical peels or non-ablative lasers in patients currently or recently exposed to isotretinoin. Medium-depth and deep peels, ablative laser and mechanical dermabrasion are not among the procedures it cleared.[6] That is a finding to take to the prescriber, not a decision to make around them.

There is a second, less-discussed responsibility. NICE asks that anyone on oral isotretinoin has their psychological wellbeing reviewed during treatment and is monitored for developing or worsening mental health problems or sexual dysfunction.[1]

You may see that client more often than their prescriber does. You are not monitoring them — but if someone tells you in a treatment room that they have felt awful since starting, the right response is to tell them to contact their prescriber, and to mean it.

What remains uncertain#

  • Whether any chemical peel is consistently better than another for acne. Twelve small trials could not establish it — in either direction.
  • Whether phylotype-targeted or biofilm-targeted approaches translate into clinical benefit. The microbiology is ahead of the therapeutics.
  • The role of diet, which NICE currently describes as insufficiently evidenced rather than disproven.
  • Whether professional treatments alongside guideline therapy improve outcomes, adherence or neither — almost nothing tests the combination.
  • How much of what is sold as acne treatment in aesthetics is treating the acne and how much is treating its aftermath.

Common misconceptions#

“Acne is bacterial overgrowth.”

People with acne do not carry more C. acnes in their follicles than people without it. The shift is in diversity, phylotype and immune response.[2]

“Chemical peels are an evidence-based acne treatment.”

The only physical treatment recommended for acne in the NICE guideline is photodynamic therapy, for over-18s with moderate to severe acne, after other treatments have failed.[1]

“NICE looked at peels and LED and found they don't work.”

It found the evidence very limited and prioritised a research recommendation instead. That is an evidence gap, not a negative result — and saying otherwise is as inaccurate as the marketing it is meant to correct.[1]

“All the acne peels are basically equivalent.”

Two comparisons in the trial set did separate — glycolic acid over placebo, and salicylic with mandelic acid over glycolic acid. What could not be established was any consistent superiority across outcomes.[4]

“Cut out dairy and sugar.”

NICE's recommendation is to advise people that there is not enough evidence to support specific diets for treating acne.[1]

“Give it a few months of facials and see.”

Scarring risk rises with severity and duration. A course that delays effective treatment has a cost the client pays permanently.[1]

“It's only mild, so it doesn't warrant referral.”

NICE asks for referral consideration at any severity where acne is causing persistent psychological distress or a mental health disorder.[1]

“Long-term antibiotics are standard for acne.”

Antibiotic monotherapy is explicitly not recommended in any form, and antibiotic-containing regimens run beyond six months only in exceptional circumstances.[1]

Frequently asked questions#

Can I treat acne as a skincare professional?

You can deliver the skin care advice in the national guideline, recognise what needs referring, and treat the aftermath. Presenting a treatment course as acne therapy is a different claim, and the guideline does not support it.[1]

What should I actually tell a client to use at home?

A pH-neutral or slightly acidic syndet cleanser twice daily, non-comedogenic and oil-free skincare, sunscreen and make-up, make-up removed at night, and no picking.[1]

Their GP started treatment six weeks ago and nothing's happening.

That is expected. First-line treatment is a 12-week course, and NICE asks clinicians to explain that effects can take six to eight weeks to become noticeable. Encouraging adherence is genuinely useful here.[1]

When can I treat their acne scarring?

NICE’s England pathway applies to scarring that is severe and persists a year after the acne has cleared, and routes it to a dermatologist-led team.[1] Treat the year as a referral threshold resting on committee experience of remodelling and on resource considerations, rather than as a point before which nothing can help anyone.[1]

Is it safe to peel someone on isotretinoin?

For a superficial peel, the 2017 consensus found insufficient evidence to justify a delay — a finding for the prescriber to act on, not a green light to proceed independently.[6]

References#

Each source is graded by evidence tier. Tier 4 material (manufacturer documents, expert consensus, practitioner experience) is useful for protocol and context, and is never presented as equivalent to independent clinical evidence.

  1. National Institute for Health and Care Excellence. Acne vulgaris: management. NICE guideline NG198. Published 25 June 2021; last updated 30 April 2026.Tier 1Supports: SEVERITY DEFINITIONS: mild to moderate acne is any number of comedones, up to 34 inflammatory lesions, or up to 2 nodules; moderate to severe is 35 or more inflammatory lesions or 3 or more nodules. SKIN CARE (1.2.1–1.2.4): advise a non-alkaline, pH-neutral or slightly acidic synthetic detergent (syndet) cleanser twice daily; avoid oil-based and comedogenic skincare, sunscreens and make-up; remove make-up at the end of the day; advise that persistent picking or scratching increases scarring risk. DIET (1.3.1): 'Advise people that there is not enough evidence to support specific diets for treating acne.' REFERRAL (1.4): acne fulminans is a same-day urgent referral to the on-call hospital dermatology team for assessment within 24 hours; refer for diagnostic uncertainty, acne conglobata or nodulo-cystic acne; consider referral for mild-to-moderate acne unresponsive to two completed courses, moderate-to-severe unresponsive to a course containing an oral antibiotic, acne leading to scarring, or acne with persistent pigmentary changes; consider referral for acne of ANY severity causing persistent psychological distress or a mental health disorder. TREATMENT (1.5.1): offer a 12-week course of one of five fixed-combination first-line options. (1.5.5) positive effects can take 6 to 8 weeks to become noticeable. (1.5.7) start topical benzoyl peroxide or retinoids alternate-day or short-contact to reduce irritation. (1.5.11) 'Do not use the following to treat acne: monotherapy with a topical antibiotic; monotherapy with an oral antibiotic; a combination of a topical antibiotic and an oral antibiotic.' (1.5.13) only continue an antibiotic-containing option beyond 6 months in exceptional circumstances, reviewing 3-monthly. (1.5.6) the risk of scarring increases with the severity and duration of acne. PHYSICAL TREATMENTS — the entire section is a single recommendation (1.5.29): 'Consider photodynamic therapy for people aged 18 and over with moderate to severe acne if other treatments are ineffective, not tolerated or contraindicated.' SCARRING (1.8.2): if scarring is severe and persists a year after the acne has cleared, refer to a consultant dermatologist-led team with expertise in scarring management, and in that setting consider CO2 laser treatment (alone or after punch elevation) or glycolic acid peel. ISOTRETINOIN: standard daily dose 0.5–1 mg/kg to a cumulative 120–150 mg/kg; review psychological wellbeing during treatment and monitor for developing or worsening mental health problems or sexual dysfunction.
  2. Dréno B, Pécastaings S, Corvec S, Veraldi S, Khammari A, Roques C. Cutibacterium acnes (Propionibacterium acnes) and acne vulgaris: a brief look at the latest updates. Journal of the European Academy of Dermatology and Venereology. 2018;32(Suppl 2):5–14.Tier 4Supports: States verbatim: 'contrary to what was previously thought, proliferation of P. acnes is not the trigger of acne as patients with acne do not harbour more P. acnes in follicles than normal individuals. Instead, the loss of the skin microbial diversity together with the activation of the innate immunity might lead to this chronic inflammatory condition.' Also covers the taxonomic rename from Propionibacterium to Cutibacterium acnes and the phylogenetic cluster groups.Funding / interest: A narrative review published in a JEADV supplement issue rather than the main journal. Supplement issues are commonly industry-supported; the specific funding for this article was not verified. Treat as expert opinion, not as an independent systematic assessment.
  3. Cavallo I, Sivori F, Truglio M, et al. Skin dysbiosis and Cutibacterium acnes biofilm in inflammatory acne lesions of adolescents. Scientific Reports. 2022;12:21104.Tier 3Supports: Microbiota analysis in adolescents. Significantly lower alpha diversity in inflammatory lesions than in non-inflammatory lesions of acne patients and in healthy subjects. Differences at species level were driven by overabundance of C. acnes AT THE INFLAMED SITE. Phylotype IA1 was more represented in acne patients than healthy subjects, and IA1 isolates showed more efficient early adhesion, greater biomass production and significantly increased antibiotic tolerance. The authors' framing is site-specific dysbiosis and virulent phylotype colonisation 'despite the universal carriage of the microorganism'. NOTE this partially qualifies the Dréno statement: the total-carriage argument and the lesion-site abundance finding are not the same measurement.Funding / interest: One co-author is affiliated with Biofilm Pharma SAS, a commercial company, in a paper concluding that biofilm-targeting antimicrobials may represent potential treatments. The authors declare no competing interests.
  4. Chen X, Wang S, Yang M, Li L. Chemical peels for acne vulgaris: a systematic review of randomised controlled trials. BMJ Open. 2018;8(4):e019607.Tier 1Supports: 12 randomised controlled trials, 387 participants; databases searched via OvidSP to April 2017. Commonly used chemical peels appeared similarly effective for mild-to-moderate acne and well tolerated, at very low to moderate methodological quality, with meta-analysis impossible because of clinical heterogeneity. TWO COMPARISONS DID SEPARATE and must not be flattened into 'none was superior': glycolic acid peeling was superior to placebo, and combined salicylic and mandelic acid peeling was superior to glycolic acid peeling. Conclusion verbatim: 'a robust conclusion cannot be drawn regarding any definitive superiority or equality among the currently used chemical peels'. That is a failure to establish superiority, NOT a finding of equivalence.
  5. Abdel Hay R, Shalaby K, Zaher H, et al. Interventions for acne scars. Cochrane Database of Systematic Reviews. 2016;(4):CD011946.Tier 1Supports: 24 trials, 789 adults. A lack of high-quality evidence across acne scar interventions, attributed to poor methodology, underpowered studies, no standardised assessment of improvement and differing baselines. On needling specifically, no comparison rose above low-quality evidence.
  6. Waldman A, Bolotin D, Arndt KA, et al. ASDS Guidelines Task Force: consensus recommendations regarding the safety of lasers, dermabrasion, chemical peels, energy devices, and skin surgery during and after isotretinoin use. Dermatologic Surgery. 2017;43(10):1249–1262.Tier 1Supports: Found insufficient evidence to justify delaying superficial chemical peels or non-ablative lasers in patients currently or recently exposed to isotretinoin. The cleared list is closed; medium-depth and deep peels, ablative laser and mechanical dermabrasion are not on it.
  7. Welsh Government. National Institute for Health and Care Excellence (NICE) guidelines. GOV.WALES. First published 8 June 2020, last updated 11 September 2024.Tier 1Supports: Verbatim: 'We have an agreement that all NICE guidelines and quality standards are available to use in Wales. Except for technology appraisal guidance (TAGs), their use is not mandatory. All NICE guidance used in Wales is subject to Welsh legislation.' Registered here to stop NG198 being described as a UK-wide pathway.
  8. Department of Health (Northern Ireland) / Strategic Planning and Performance Group. NICE Guidelines.Tier 1Supports: Verbatim: 'NICE guidance, published from 1 July 2006, is reviewed locally for its applicability to Northern Ireland and, where found to be applicable, is endorsed by the Department for implementation in Health and Social Care (HSC).' NICE guidance is therefore not automatically applicable in Northern Ireland; a revised governance process took effect on 18 December 2013.

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Skinipedia is written by the educators at MSTA, the medic-led skincare training academy in Liverpool.