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Comedonal acne is the pattern dominated by blackheads and whiteheads — open and closed comedones — driven by follicular plugging with little inflammation. It is not caused by dirty skin. First-line is over-the-counter actives (salicylic acid, adapalene, benzoyl peroxide), then prescription topical retinoids. One tier gets 8–12 weeks before stepping up.

Acne pattern

Comedonal Acne

Comedonal acne is the pattern of acne dominated by blackheads and whiteheads — open and closed comedones — with little surrounding inflammation. It is caused by follicular plugging rather than infection, and it is not caused by dirty skin. It is the mildest of the acne patterns and usually the most responsive to a consistent topical routine, but it needs the right actives used for long enough, and it can progress to inflammatory acne if the plugging continues.

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By Dr Christopher Irwin, MBChB, FRACGP, MMed (Skin Cancer), FACAM, MSCCA

Last reviewed 2026-07-26 · Editorial policy

Comedonal acne is the pattern of acne made up mostly of comedones — blackheads and whiteheads — with little surrounding inflammation. It is driven by follicular plugging rather than infection, it is not caused by dirty skin, and it is usually the most responsive acne pattern to a consistent topical routine. (1)

What comedonal acne looks like

Comedonal acne presents as open comedones (blackheads) and closed comedones (whiteheads) — follicular plugging with little inflammation. The dark colour of blackheads comes from oxidised material and pigment, not dirt. Lesions occur commonly on the face, chest, back and jawline.

Compared with inflammatory acne, there is little of the surrounding redness and tenderness that comes with papules and pustules — which is also why this pattern carries a lower scarring risk, and why the goal of treatment is to keep it from escalating.

Where it begins — the microcomedo

The earliest acne lesion is microscopic: a microcomedo, a tiny plug formed by sticky keratin cells inside the lower part of the follicle. Over time, this can evolve into visible acne lesions:

  • When sebum and keratin accumulate behind the plug, it becomes a closed comedo (whitehead).
  • As the pore opening stretches, it can become an open comedo (blackhead). The dark colour comes from oxidised material and pigment — not dirt. Oxidation is exactly the same as how the inside of an apple turns brown if you take a few bites out of it and leave it open to the air for a few hours.
  • If inflammation escalates, papules and pustules develop. If the follicle wall ruptures, inflammation can spill into the deeper skin and form a nodule, increasing scarring risk. (1)

This is why acne treatment focuses on preventing plugs and calming inflammation early.

Increased oil (sebum) production contributes by promoting follicle blockage, and changes in the follicle microbiome — especially Cutibacterium acnes — are part of the picture too. Acne is not simply an infection; what appears to matter is an imbalance rather than “too much bacteria”. (2)

Why scrubbing does not work

Acne is not caused by dirty skin. In fact, harsh scrubbing, strong astringents and irritant routines can rupture comedones and worsen inflammation — disrupting the skin barrier and triggering more of exactly the process you are trying to settle. (1)

A gentle, barrier-friendly routine is the foundation of treating this pattern, not an optional extra alongside it.

How comedonal acne is treated

Evidence-based over-the-counter actives — salicylic acid, adapalene and benzoyl peroxide — are first-line for mild acne. Where that is not enough, prescription topical therapy adds a topical retinoid (adapalene, tretinoin) combined with benzoyl peroxide and/or topical antibiotics — first-line evidence-based treatment for mild-to-moderate acne. (1)

Because the target is follicular plugging, topical actives are used across the affected area continuously rather than dabbed onto individual spots.

Our over-the-counter acne treatments guide → sets out the actives and typical strengths in detail, and prescription acne treatments → covers the next tier. For the supporting routine around them — cleanser, moisturiser and sunscreen — see skincare for acne-prone skin →.

When it might not be comedonal acne

Not every small bump is a comedone. Milia → are firm keratin cysts that look like whiteheads but do not respond to acne actives, and keratosis pilaris → produces rough, uniform papules on the upper arms, thighs or cheeks. If the plugging pattern is not behaving as expected, the diagnosis is worth revisiting.

When to see a doctor

See a doctor if a structured over-the-counter routine has not worked after 8–12 weeks, if inflamed papules and pustules are developing on top of the comedones, if anything is starting to scar, or if your skin is affecting your confidence at any severity. Inflammatory acne is far more likely to scar than purely comedonal acne — and scarring is irreversible, so prevention is far easier than treatment.

Book an acne consultation

This page covers one pattern. For the full picture — all four patterns, the staged treatment ladder and what acne leaves behind — see our acne hub →, or read about inflammatory acne → if red, tender pimples are the bigger problem.

Symptoms

Causes & contributors

Diagnosis

Comedonal acne is diagnosed clinically by a doctor. Assessment grades severity (mild, moderate, severe) and identifies the predominant lesion type — comedonal, inflammatory or nodulocystic — because the predominant lesion type is what determines the right starting treatment. The earliest acne lesion is microscopic: a microcomedo, a tiny plug formed by sticky keratin cells inside the lower part of the follicle, which can then evolve into the visible whiteheads and blackheads of this pattern.

Treatment options

Over-the-counter and skincare optimisation

Gentle, barrier-friendly routine — harsh scrubbing and irritating products often make acne worse. Evidence-based over-the-counter actives (salicylic acid, adapalene, benzoyl peroxide) are first-line for mild acne.

Prescription topical therapy

Topical retinoids (adapalene, tretinoin) combined with benzoyl peroxide and/or topical antibiotics for mild-to-moderate acne. First-line evidence-based treatment.

When to see a doctor

See a doctor if your acne is not responding to a structured over-the-counter routine after 8–12 weeks, if inflamed papules and pustules are developing on top of the comedones, if any lesion is starting to scar, or if the appearance of your skin is causing significant distress at any severity. Scarring is irreversible and prevention is far easier than treatment, so the point of review is before inflammation becomes established — not after.

Frequently asked questions

  • What is comedonal acne?
    Comedonal acne is the pattern of acne made up mostly of comedones — blackheads (open comedones) and whiteheads (closed comedones) — with little surrounding inflammation. It is driven by follicular plugging — sticky keratin cells form a microscopic plug inside the follicle, and sebum and keratin then accumulate behind it. It is the mildest acne pattern and usually the most responsive to a consistent topical routine.
  • Why are blackheads dark if they are not dirt?
    The dark colour of a blackhead comes from oxidised material and pigment — not dirt. A blackhead is an open comedo — the pore opening has stretched, exposing the plugged contents to air. This is why scrubbing does not clear blackheads, and why harsh scrubbing and irritating products often make acne worse by disrupting the skin barrier and triggering more inflammation.
  • What is the difference between a whitehead and a blackhead?
    Both are comedones — plugged follicles. When sebum and keratin accumulate behind a plug that remains closed, it becomes a closed comedo (whitehead). As the pore opening stretches and the plugged contents are exposed to air, it becomes an open comedo (blackhead). Both respond to the same category of treatment — actives that prevent follicular plugging.
  • What treats comedonal acne?
    Evidence-based over-the-counter actives — salicylic acid, adapalene and benzoyl peroxide — are first-line for mild acne, used within a gentle, barrier-friendly routine. If that is not enough, prescription topical therapy adds a topical retinoid (adapalene, tretinoin) combined with benzoyl peroxide and/or a topical antibiotic. Because acne treatment focuses on preventing plugs, topical actives are used continuously rather than only on individual spots.
  • How long does comedonal acne take to clear?
    Acne treatments work slowly. One treatment tier, used properly and consistently, gets 8–12 weeks before judging it — and if your skin is not clearly better after 8–12 weeks, the answer is usually to step up to the next tier rather than restart the same one. See a doctor if a structured over-the-counter routine has not worked in that time.
  • Can comedonal acne turn into inflammatory acne?
    Yes. If inflammation escalates around a plugged follicle, papules and pustules develop, and if the follicle wall ruptures, inflammation can spill into the deeper skin and form a nodule. Inflammatory acne is far more likely to scar than purely comedonal acne, which is why treating the plugging early — and stepping up when a tier is not working — matters.

References

  1. Zaenglein AL, Pathy AL, Schlosser BJ, et al. Guidelines of care for the management of acne vulgaris. J Am Acad Dermatol. 2016;74(5):945–973.e33.
  2. O'Neill AM, Gallo RL. Host-microbiome interactions and recent progress into understanding the biology of acne vulgaris. Microbiome. 2018;6:177.

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Medically reviewed by Dr Christopher Irwin, MBChB, FRACGP, MMed (Skin Cancer), FACAM, MSCCA · Last reviewed 2026-07-26 · Editorial policy