Acnepimples and blackheads

What is acne?

Acne is an inflammation of the skin with pimples and blackheads, also known as spots. It is one of the most common skin conditions in the world. Almost everyone develops acne during puberty. For some people, it is limited to a few pimples; for others, it is more widespread and has a greater impact. Acne can continue after puberty or start in adulthood. It is a visible condition that can be quite distressing and may cause psychological distress.

How does acne develop?

Acne is an inflammation around the hair follicles and sebaceous glands. Various factors cause a follicle to become blocked. This is how blackheads (comedones) form. A blocked follicle contains bacteria, and inflammation can follow. Sometimes this inflammation is severe. That is called acne conglobata, and it mainly affects men.

Acne can also come from outside factors. Think of follicles blocked by make-up and oil-based products. Medicines and supplements can cause or worsen acne too, for example vitamin B12.

Acne is not caused by poor hygiene or a vitamin deficiency. There is little evidence that a specific diet or supplements improve acne. The advice is to eat a varied and healthy diet.

What triggers acne or makes it worse?

Acne rarely has a single cause. Hormones and genetic predisposition are the main causes. There are also factors that can trigger acne or make it worse.

What is not a cause: poor hygiene or a vitamin deficiency.

What types of acne are there?

Not all acne looks the same, and that difference matters: the type of acne determines which treatment makes the most sense. Acne vulgaris is the most common form and the umbrella term for acne caused by blocked sebaceous glands.

Comedonal acne. Mainly open and closed comedones and little inflammation.

Hormonal acne. Spots that follow hormonal fluctuations, often on the jawline, chin and cheeks.

Inflammatory acne. Red, swollen pimples and pustules with a white or yellow head. With this presentation, early treatment can make a big difference.

Cystic acne. A severe form in which the inflammations sit deep in the skin, with large, red and painful bumps.

Acne conglobata. A rare, very severe form in which inflammations merge into large abscesses.

There are also two presentations that work slightly differently. In acne excoriée, picked spots and small wounds dominate the picture. And when acne first appears after the age of twenty-five, we call it acne tarda, also known as adult acne.

What does acne look like?

Acne consists of blackheads (comedones), red bumps and pimples. A blackhead is a white or black bump on the follicle, a build-up of dead skin cells. Sometimes larger inflammations (abscesses) develop. Scars can remain after healing. The more severe and the longer the acne lasts, the greater the risk of scarring.

Acne is not limited to the face. The back, chest and shoulders are the next most common areas. About half of the people with facial acne also have acne on the trunk.

Acne looks different on every skin. On lighter skin an inflammation can look bright red or pink. On darker skin the redness can be more subtle, and dark marks after an inflammation can be more noticeable.

Is acne contagious?

How does your doctor diagnose acne?

Your doctor usually recognises acne straight away from the skin. Extra tests are almost never needed. The severity is assessed from the number of bumps and pimples and how widespread it is: mild, moderate or severe. Whether there are scars also counts.

How is acne treated?

Dermatologists treat acne in steps, following the guidance of their professional association. First topical treatments, then stronger options through a doctor if these are not enough. Which step fits you depends on the type of acne, the severity and the risk of scarring. The guideline is also restrained with antibiotics: only when needed, always combined with a topical treatment, and always for a limited period.

Acne almost always needs long-term treatment. There are several options. Depending on the cause, acne cannot always be cured. Usually it is possible to calm the acne and keep it calm until it clears on its own.

Treatment often starts with a cream, gel or lotion. This is often a combination of ingredients that exfoliate and work against bacteria and inflammation. Examples are benzoyl peroxide, retinoids (such as tretinoin and adapalene) and antibiotics (such as clindamycin). Sometimes a course of antibiotics is added. The most commonly used is doxycycline. This treatment is often given for 3 months.

For severe acne, a tablet treatment with isotretinoin is started. This medicine contains an ingredient derived from vitamin A. Isotretinoin reduces sebum production and reduces the hardening of the skin, so the ducts of the sebaceous gland and follicle are less likely to become blocked. It also suppresses inflammation. The most common side effect is dryness of the lips, the lining of the nose, the eyes and the skin. Liver values and blood fats can sometimes rise during treatment. Regular blood tests are therefore needed. Isotretinoin carries serious risks during pregnancy. Women and girls must therefore not become pregnant during treatment and, if of childbearing age, must take a monthly pregnancy test. This treatment lasts an average of 9 months, but this varies from person to person. See also the isotretinoin leaflet.

The contraceptive pill can also reduce sebum production and so have a beneficial effect on acne. It is recommended for women who already want to use the pill alongside their acne treatment. Your doctor will discuss this with you.

Your doctor can also refer you to a skin therapist for skincare advice and supportive treatments. Acne can affect your mood. Psychological support can help some people.

What can you do yourself?

What does not work, or is not proven?

Stubborn myths surround acne. Here is what the research shows.

Worse first, then better: the first weeks

Many acne treatments require an adjustment period. In the first two to six weeks your skin can be drier, redder and more sensitive than usual. Some people even see slightly more pimples at first. That is well known and passes.

The effect of an acne treatment is only assessed after six to twelve weeks. So do not stop too early: most people who give up do so just before the result becomes visible.

Preventing scars and marks

An inflamed pimple damages the connective tissue in the deeper layer of the skin. Usually the skin repairs this neatly. But when the inflammation sits deep or lasts long, the repair sometimes goes wrong. A small pit forms in the skin, or a thickened area. That is a scar, and it no longer disappears on its own.

Red or dark marks left after a pimple are not scars but pigment changes. Those usually do fade.

The most important predictor is time. The longer an inflammation stays active, the greater the chance of permanent damage. Early treatment is therefore the best scar prevention there is. Beyond that, leave pimples alone, do not use aggressive scrubs and protect your skin from the sun during the day, because sunlight makes discolouration darker and more stubborn.

Does acne go away?

For many people acne calms down over the years. Depending on the cause, acne cannot always be cured, but it is usually possible to calm the skin and keep it calm until it clears on its own.

Important to know: a treatment suppresses the process in your skin, but does not take away the predisposition. Stop from one day to the next, and the pimples often start again within weeks to months. That is why maintenance is usually a light continuation of your treatment, at a lower frequency. If you want to reduce or stop, do it step by step and in consultation with your doctor.

Acne and your mood

Acne is a visible condition that can be quite distressing and may cause psychological distress. Acne can affect your mood. Psychological support can help some people. If your skin weighs on you, mention it in your consultation, and the dermatologist will look at what helps.

Acne-like rash during cancer treatment

Some cancer treatments cause a side effect that looks like acne. Yet it is slightly different: ordinary spots mainly appear during puberty and come with blackheads. This skin side effect can occur at any age and often has no blackheads. That is why it is called an 'acne-like rash'.

You can develop this side effect during treatment for cancer with certain medicines. This is mainly with newer cancer treatments such as eGFR, MEK and mTOR inhibitors. It can also result from supportive treatment with prednisolone. With chemotherapy, an acne-like rash is a rare side effect. The rash often appears in the first 4 weeks after the treatment starts, with red bumps and pimples on sun-exposed areas and on parts of the body with many sebaceous glands.

This information is based on guidance from the EADV Dermatology for Cancer Patients Task Force.

Frequently asked questions about acne

Sources and more information

• NVDV patient leaflet Acne vulgaris, version 2022
• NVDV patient leaflet Acne-like rash during cancer treatment (EADV), version 2022
• NVDV Acne Vulgaris guideline, 2022 revision
• NHG Practice Guideline Acne
• The Acne Guide 2026, 247dermatologist