Acne is a chronic skin condition that affects most people at some point during their life. It causes spots to develop on the skin, usually on the face, back and chest. The symptoms of acne can be mild, moderate or severe.

Acne is thought to be caused by changes in hormones that are triggered during puberty.

Acne can cause great distress and have an adverse effect on a person's quality of life and self-esteem.

Therefore, healthcare professionals recognise that the condition requires effective and sometimes aggressive treatment.

How common is it?

Acne is the most common type of skin condition. It is most widespread among older children, teenagers and young adults. 

Around 80% of 11 to 30-year-olds are affected by acne. Most acne cases in girls occur between the ages of 14 to 17, and in boys the condition is most common in 16 to 19- year-olds.

Most people will experience repeated episodes, or flare-ups, of acne for several years before finding that their symptoms gradually start to improve as they get older. The symptoms of acne usually disappear when a person is in their twenties.

However, in some cases, acne can continue into adult life, with approximately 5% of women and 1% of men over 25 continuing to experience symptoms.


With treatment, the outlook for acne is generally good. Treatments can take between two to three months to work but, once they do, the results are usually effective.

Approximately 90% of people who seek treatment for acne will show at least a 50% improvement in their symptoms after three months. Once the symptoms are under control, additional treatments can be used to prevent the acne from recurring. This is known as maintenance therapy.

In cases of severe acne, scarring can occur. However, this can usually be prevented by seeking prompt treatment.


A nodule is a small growth or lump of tissue.
The onset is the beginning or early stages of a condition or disease.

Acne myths

Despite being one of the most widespread skin conditions, acne is also one of the most poorly understood and there are a wide range of myths and misconceptions about it. These are explained below.

  • 'Acne is caused by a poor diet.' There is no evidence that diet plays a role in acne. Eating a healthy, balanced diet is recommended because it is good for your heart and your health in general. However, it will not help your acne.
  • 'Acne is caused by having dirty skin and poor hygiene.' Most of the biological reactions that trigger acne occur beneath the skin, not on the surface of the skin. Therefore, how clean your skin is will have little to no effect on your acne. You should wash on a daily basis (and your face twice a day). More frequent washing will make no difference to your acne and could actually make your symptoms worse by aggravating your skin.
  • 'Squeezing blackheads, whiteheads, and spots is the best way to get rid of acne.' Squeezing or picking your acne could make your symptoms worse and may leave you with permanent scarring.
  • 'Sunbathing, sunbeds and sunlamps help improve the symptoms of acne.' There is no conclusive evidence that prolonged exposure to sunlight, or using sunbeds or sunlamps can improve acne. However, there is evidence to show that prolonged exposure to sunlight can increase your risk of getting skin cancer. Also, many of the medications that are used to treat acne can make your skin more sensitive to light, so prolonged exposure could cause painful damage to your skin.
  • ‘Acne is infectious.’ You cannot pass acne on to other people and the condition is not infectious.

Acne most commonly develops on:

  • the face: affecting 99% of all people with the condition,
  • the back: affecting 60% of all cases, and
  • the chest: affecting 15% of all cases.

Types of spots

Acne causes skin lesions that are commonly referred to as spots. A lesion is the medical term for damaged tissue.

There are six main types of spot caused by acne. These are described below.

  • Blackheads: small black or yellowish bumps that develop on the skin.
  • Whiteheads: have a similar appearance to blackheads but they can be firmer and have a white centre.
  • Papules: small red bumps that may feel tender or sore.
  • Pustules: similar to papules but they have a white tip in the centre that is caused by a build-up of pus.
  • Nodules: large hard lumps that build up beneath the surface of the skin and are usually painful.
  • Cysts: the most serious type of spot caused by acne. They are large, pus-filled lumps that look similar to boils. Cysts carry the greatest risk of causing permanent scarring.

When to seek medical advice

For some people, even mild cases of acne can cause distress. Therefore, if your acne is making you feel very unhappy, you should visit your GP.

Also see your GP if you develop nodules or cysts, because these are usually associated with severe acne. If necessary, your GP can then refer you to a dermatologist (an expert in treating skin conditions).



A nodule is a small growth or lump of tissue.

To understand better the causes of acne, it is useful to learn more about the sebaceous glands, which play a key role in the condition's development.

Sebaceous glands

Sebaceous glands are tiny glands found near the surface of your skin. The glands are attached to hair follicles. A hair follicle is a small hole in your skin that an individual hair grows out of.

The purpose of sebaceous glands is to lubricate the hair and the skin in order to stop it drying out. The glands do this by producing an oily substance called sebum. In acne, the glands begin to produce too much sebum. The excess sebum mixes with dead skin cells and both substances form a plug in the follicle.

If the plugged follicle is close to the surface of the skin, it will bulge outwards, creating a whitehead. Alternatively, the plugged follicle can be open to the skin, creating a blackhead.

Normally harmless bacteria that live on the skin can then contaminate and infect the plugged follicles, resulting in papules, pustules, nodules, and cysts. See types of spots.

The triggers of acne


Cases of teenage acne are thought to be triggered by increased levels of a hormone called testosterone that occurs during puberty. The hormone plays an important role in stimulating the growth and the development of the penis and testicles in boys, and maintaining muscle and bone strength in girls.

The sebaceous glands are particularly sensitive to hormones, so it is thought that the increased testosterone causes the glands to produce much more sebum than the skin actually needs.


In cases of adult acne, over 80% of cases occur in women. It is thought that many cases of adult acne are a result of the changes in hormone levels that many women will experience at certain points during their life. Possible triggers for adult acne include:

  • Periods: some women experience a flare-up of acne just before their period is due.
  • Pregnancy: many women experience symptoms of acne during pregnancy, usually during the first trimester (first three months).
  • Polycystic ovary syndrome: this poorly understood, but common condition can cause acne, weight gain and the formation of small cysts inside the ovary.
  • Side effects of medication: in some people, certain types of medication can cause acne, e.g. steroid medication and lithium (which is often used to treat depression and bipolar disorder).


Testosterone is a male sex hormone, which is involved in making sperm and sexual characteristics such as the voice getting deeper. Testosterone is also found in small amounts in women.
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.
Genetic is a term that refers to genes- the characteristics inherited from a family member.
A nodule is a small growth or lump of tissue.
Ovaries are the pair of reproductive organs that produce eggs and sex hormones in females.

Your GP will be able to make an initial diagnosis of acne based on the appearance of your skin. This will involve examining your face, chest and back for the different types of spot, such as blackheads or sore, red nodules.

The number of spots that you have, and how painful and inflamed they are, will help your GP to assess the severity of your acne, which plays an important part in the planning of your treatment.

Acne is classified as mild, moderate or severe. The severities are described below.

  • Mild acne: where you mostly have blackheads and whiteheads that are usually confined to your face.
  • Moderate acne: where you have a combination of whiteheads, blackheads, papules and pustules that may extend to your shoulders and back.
  • Severe acne: as well as the papules and pustules, you also have nodules and cysts and the spread of the acne may be extensive.

Your GP will discuss with you the history of your symptoms and any previous treatments that you have used, including over-the-counter (OTC) products. You may also want to discuss the psychological effects of having acne and whether it makes you feel upset or embarrassed.


A nodule is a small growth or lump of tissue.

Your treatment plan

Your recommended treatment plan will depend on whether your acne is mild, moderate or severe.

Mild acne is treated using gels or creams (topical treatments) such as:

  • benzoyl peroxide,
  • topical retinoids,
  • topical antibiotics, or
  • azelaic acid.

Moderate acne is usually treated using a combination of the medications that are mentioned above. In some cases, antibiotic tablets (oral antibiotics) may also be used.

If you have severe acne, you will usually be referred to a dermatologist (an expert in treating skin conditions). A combination of oral antibiotics and topical treatments (see below) are usually the first treatment option. If this proves to be ineffective, a medication called isotretinoin (Roaccutane) may be prescribed.

Benzoyl peroxide

Benzoyl peroxide works in two ways:

  • it helps prevent dead skin plugging up hair follicles.
  • it kills the bacteria on the skin that can cause plugged follicles to become infected.

Benzoyl peroxide is usually available in cream or gel form and used either once or twice a day. It should be applied, 20 minutes after washing, to all of the parts of your face affected by acne. It should be used sparingly as too much can harm your skin.

Benzoyl peroxide makes your face more sensitive to sunlight, so you should avoid excessive exposure to sunlight and ultra-violet (UV) light, or wear sun cream.

Avoid contact with hair, clothes, towels and bed linen, as benzoyl peroxide can bleach these materials. Wash your hands after you finish applying the medication.

Common side effects of benzoyl peroxide include:

  • dry and tense skin,
  • a burning, itching, or stinging sensation, and
  • some redness and peeling of the skin.

Side effects are usually mild and should pass once the treatment has finished. Contact your GP if side effects become troublesome, as your dose may need to be adjusted.

Most people require a six-week course of treatment to clear most or all of their acne. You may be advised to continue treatment but less frequently to prevent acne returning.

Topical retinoids

Topical retinoids work by reducing the production of sebum while also preventing dead skin cells plugging hair follicles.

Tretinoin and adapalene are used to treat acne. They are available in a gel or cream and usually applied once a day before going to bed.

Apply it to all of the parts of your face affected by acne, 20 minutes after washing your face.

It is important to apply topical retinoids sparingly and avoid excessive exposure to sunlight and UV.

Topical retinoids are not suitable for use during pregnancy as they carry a risk of causing birth defects.

The most common side effects of topical retinoids are mild irritation and stinging of the skin.

A six-week course is usually required but you may be advised to continue medication after this on a less frequent basis.

Topical antibiotics

Topical antibiotics help kill the bacteria on the skin that can infect plugged hair follicles.

Topical antibiotics are available as a lotion or gel and applied once or twice a day.

A six to eight-week course is usually recommended. After this, treatment is usually stopped as there is a risk that the bacteria on your face could become resistance to the antibiotics. This could make your symptoms worse and cause additional infections.

Side effects are uncommon but can include:

  • minor irritation of the skin,
  • redness and burning of the skin, and
  • peeling of the skin.

Azelaic acid

Azelaic acid is often used as an alternative treatment for acne if the side effects of benzoyl peroxide or topical retinoids are particularly irritating or painful.

Azelaic acid works by getting rid of dead skin and killing bacteria.

It is available in cream or gel form and is usually applied twice a day (or once a day if your skin is particularly sensitive).

The medication does not make your skin sensitive to sunlight so you do not have to avoid sun exposure.

You will usually need to use azelaic acid for a month before you notice a significant improvement in your symptoms.

The side effects of azelaic acid are usually mild and include:

  • burning or stinging skin,
  • itchiness,
  • dry skin, and
  • redness of the skin.

Oral antibiotics

Oral antibiotics are usually used in combination with a topical treatment to treat moderate to severe acne.

In most cases, a class of antibiotics called tetracyclines is prescribed. Pregnancy or breastfeeding women are usually advised to take an antibiotic called erythromycin, which is known to be safer to use during pregnancy and breastfeeding.

It will usually take about six weeks to notice a significant improvement in your symptoms. Depending on how well you react to the treatment, a course of oral antibiotics can last between four to six months. Treatment is usually stopped after six months to reduce the risk of antibiotic resistance.

Side effects of tetracyclines include:

  • nausea,
  • vomiting, and
  • diarrhoea.

Tetracyclines can make your skin sensitive to sunlight and UV light and also make the oral contraceptive pill less effective during the first few weeks of treatment.You will need to use an alternative method of contraception, such as a condom, during this time.

The most common side effects of erythromycin are:

  • nausea, and
  • mild stomach pain.

Taking erythromycin with food should help to reduce the severity of these side effects.


Women with acne who require contraception are advised to take a type of oral contraceptive (the pill) called co-cyprindiol. One of the beneficial side effects of co-cyprindiol is that it helps to improve the symptoms of acne.

You will probably have to use co-cyprindiol for between two to six months before you notice a significant improvement in your acne.

The side effects of co-cyprindiol are similar to other oral contraceptives and include:

  • breast tenderness
  • weight gain, and
  • mood changes, such as irritability or low mood.


Isotretinoin works in the same way as topical retinoids but the medication has a much stronger effect. Due to this, isotretinoin can only be prescribed by a dermatologist (an expert in treating skin conditions) and not by your GP. Isotetinoin is used with caution with people who suffer from depression

Isotretinoin is taken in tablet form, with most people taking four to six-month course. You may find that your acne gets worse during the first seven to 10 days of treatment. However, this is normal and is caused by the medication pushing out bacteria present in the deeper layers of your skin.

Isotretinoin carries a very high risk of causing serious birth defects.

If you are a woman of childbearing age, you will only be prescribed isotretinoin following a negative pregnancy test.This is repeated throughout treatment.

Contact your dermatologist immediatel if you think you might be pregnant, either during treatment or in the first month after treatment.

Common side effects of isotretinoin are listed below.

  • Inflammation, dryness and cracking of the skin and lips. This can usually be relieved by applying moisturising cream and lip balm.
  • The inside of your nose may become dry, leading to mild nosebleeds Applying a thin layer of petroleum jelly to the inside of your nose should help.
  • Headaches.
  • Skin rash. Mild itching and a slight peeling of the skin.
  • Inflammation of your eyelids (blepharitis).
  • Inflammation and irritation of your eyes (conjunctivitis).
  • Back, muscle and joint pain. This is usually worse during and after exercise.
  • Blood in your urine.
  • You may bleed and bruise more easily.

In recent years, there have been a number of news stories about people committing suicide while taking isotretinoin, prompting speculation that the medication may cause depression and suicidal thoughts.

There is no medical evidence to support this.

You should contact your GP or your dermatologist immediately if:

  • you experience a sudden mood change, such as anxiety or depression or, if you are already depressed, a sudden worsening of your depression,
  • you experience aggressive or violent thoughts or tendencies,
  • you begin to think suicidal thoughts, or
  • you begin to act in ways that you would never normally do.


Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Treatment Pros Cons
Gel or cream to unblock pores and kill bacteria
Benzoyl peroxide. This works as a peeling agent, increasing skin turnover. It kills bacteria, reduces inflammation, and helps to unplug blocked pores
  • Available in pharmacies
  • Effective in treating mild acne
  • Can stain sheets, clothes, etc
  • Can make skin more sensitive to sunlight, mild burning, itchiness, redness of skin
Vitamin A gel or cream

Gels or creams known as topical (rub-on) retinoids are derived from vitamin A. They unblock pores, and reduce production of skin oil (sebum)

  • Effective clearing whiteheads, blackheads and smaller spots
  • Not suitable in pregnancy
  • Possible side effects: make skin more sensitive to sunlight, mild irritation, stinging of the skin
Antibiotic gel or cream

Topical (rub-on) antibiotics are used to kill bacteria

  • Effective in treating inflamed spots
  • Less irritation to the skin than other anti-acne creams or gels
  • May be less effective on blackheads and whiteheads
  • Can only be used for up to eight weeks due to the risk of antibiotic resistance
Azelaic acid gel or cream
Azelaic acid unblocks pores and kills bacteria
  • Effective for mild acne for people who find side effects of other treatments troublesome
  • Does not make skin sensitive to sunlight
  • Month before symptoms improve
  • Can cause mild burning, stinging, dryness, itchiness of the skin
Antibiotic medicines

Taken by mouth, these kill bacteria and are usually used in combination with a gel or cream

  • Effective in treating mild to severe acne
  • Six weeks before improvement in symptoms
  • Makes contraceptive pill less effective; alternative contraception should be used
  • Can only be used for six months due to the risk of antibiotic resistance
  • Can make skin more sensitive to sunlight, nausea, vomiting, diarrhoea and mild stomach pains
Vitamin A medicine
Isotretinoin, taken in capsules or tablets, is derived from vitamin A. It works in the same way as retinoid gel or cream but is more powerful
  • Effective in treating severe acne
  • Can only be prescribed by dermatologist, not by a GP
  • High risk of causing serious birth defects in women, reliable contraception must be used
  • Can cause inflammation and dryness of lips, nosebleeds, headaches, inflammation of the eyelids and/or eyes, skin rashes, muscle, joint and bone pain, blood in urine, causes a person to bruise and bleed more easily

Acne scarring

Acne scarring can sometimes develop as a complication of acne when the most serious types of spots, nodules and cysts, rupture (burst) damaging nearby skin.

Scarring can also occur if you pick or squeeze your spots, so it is important to avoid doing this.

There are three main types of acne scars:

  • Ice-pick scars: small, deep holes in the surface of your skin that look like the skin has been punctured with a sharp object.
  • Rolling scars: caused by bands of scar tissue that form under the skin giving the surface of the skin a rolling and uneven appearance.
  • Boxcar scars: round or oval depressions, or craters, in the skin.

Availability of treatment for scarring

Treatments for acne scarring are regarded as a type of cosmetic surgery. As cosmetic surgery is elective, non-essential surgery, it is not usually available on the NHS. However, in the past, exceptions have been made when it has been shown that acne scarring has caused serious psychological distress.

See your GP if you are considering having cosmetic surgery. They will be able to discuss your options with you, and advise you about the likelihood of having the procedure carried out by the HSE

It is important that you have realistic expectations about what cosmetic treatment can achieve. While treatment will certainly be able to improve the appearance of your scars, it will not be able to get rid of them altogether. Following treatment for acne scarring, most people will notice a 50% to 75% improvement in appearance.

Types of treatment for scarring

Some of the available treatments for acne scarring are explained below.


Dermabrasion involves removing the top layer of skin using either lasers or a specially made wire brush.

After the procedure, your skin will look red and sore for several months, but as it heals, you should notice an improvement in the appearance of your scars.

Laser treatment

Laser treatment can be used to treat mild to moderate acne scarring. There are two types of laser treatment:

  • Ablative laser treatment: where lasers are used to remove a small patch of skin around the scar in order to produce a new smooth-looking area of skin.
  • Non-ablative laser treatment: where lasers are used to stimulate the growth of new collagen (a type of protein found in skin), which helps repair some of the damage caused by scarring and improve appearance.

Punch techniques

Punch techniques are a type of surgical treatment usually used to treat ice-pick scars and boxcar scars. There are three types of punch technique:

  • Punch excision
    Punch excision is used to treat mild ice-pick scars. The scar is surgically removed and the remaining wound is sealed. After the wound heals, it will leave a smoother and more even area of skin.
  • Punch elevation
    Punch elevation is used to treat boxcar scars. The base of the scar is surgically removed leaving the sides of the scar in place. The base is then reattached to the sides but lifted up so that it is level with the surface of the skin. This makes the scar much less noticeable.
  • Punch grafting
    Punch grafting is used to treat very deep ice-pick scars. As with a punch excision, the scar is removed, but the wound is then 'plugged' with a sample of skin that is taken from elsewhere on the body (usually from the back of the ear).


Subcision is a surgical treatment that can be used to treat rolling scars. During surgery, the upper layer of the skin is removed from the underlying scar tissue. This allows blood to pool under the affected area. The blood clot helps form connective tissue that pushes up the rolling scar so that it is level with the rest of the surface of the skin.

Once subscision has been completed, additional treatment, such as laser treatment and dermabrasion, can be used to further improve the appearance of the scar.


Acne can often cause intense feelings of anxiety and stress, which can sometimes make people with the condition become socially withdrawn. This combination of factors can lead to those with acne becoming depressed.

You (or your child) may be depressed if during the last month:

  • you (or your child) have often felt down, depressed, or hopeless, and
  • you (or your child) have little interest, or pleasure, in doing things.

If you think that you or your child may have depression, it is important that you speak to your GP.


Anxiety is an unpleasant feeling when you feel worried, uneasy or distressed about something that may or may not be about to happen.
Depression is when you have feelings of extreme sadness, despair or inadequacy that last for a long time.

Acne is not infectious and it is not caused by poor hygiene. However, a build-up of sebum (an oily substance that stops hair and skin drying out) and dead cells on the skin surface may increase the risk of blocked follicles and allow bacteria to multiply. You can help prevent this by washing your face with a gentle cleansing product. If you are wearing any make-up, make sure you wash it off before you go to bed.

There is no evidence that wearing make-up causes spots but the less you touch your skin, the fewer bacteria will be spread on your skin. To prevent the spread of bacteria, wash your hands before touching your face (for example to apply make-up).

There is also no evidence that certain foods, such as fried foods or chocolate, cause or aggravate acne. A good balanced diet is, however, important in keeping you healthy.


Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.

Content provided by NHS Choices and adapted for Ireland by the Health A-Z.

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