Pimple formation

Acne is a skin problem that usually starts in your teens. Your skin becomes greasy, skin pores become blocked and you develop whiteheads, blackheads, pimples or cysts.

Key points

  • Acne is very common in teenagers (80-90% develop some acne)
  • Acne is related to hormonal changes and is not contagious
  • Acne may improve with topical treatments available over the counter
  • Treatments may take several weeks or months to work
  • If you have persistent or severe acne, see your doctor.
  • There are other treatments that can help and sometimes referral to a dermatologist is needed.

Learn About Acne

(excellent video by Associate Professor Mike Evans, Toronto University)


During teenage years, young men and women often have a slight hormonal imbalance in favour of the male hormone testosterone. Testosterone makes the glands in hair follicles on your face, back or neck produce too much oil (sebum), which then gets clogged in the pores. Bacteria grow in the trapped oil and break it down to produce fatty substances that irritate your skin. This gives you whiteheads, blackheads, pimples or deep cysts.

How did I get acne?

  • Acne is common in teenagers because of the normal hormonal changes occurring at that age.
  • There may be a hereditary factor making it more common in some families.
  • In some girls, testosterone levels may be too high, so if your acne is severe this possibility may need to be investigated by your doctor.
  • If girls/young women have other symptoms as well as acne, such as hirsutism (excessive body/ facial hair) and irregular periods, they may have polycystic ovarian syndrome (PCOS).
  • Acne can be made worse by some drugs, such as steroids and anti-epilepsy pills, and some contraceptive pills.
  • Women may find acne gets worse around their monthly period.

Symptoms and diagnosis

Types of acne

Whiteheads - Whiteheads are round, white blemishes that form when hair follicles become blocked by a plug of sebum and dead skin cells. Blackheads - Blackheads are round, dark blemishes that form when the sebum and skin cell plug reaches the skin’s surface and the air.


Pimples are red, swollen bumps that form when the plugged follicle walls break near the skin’s surface. Deep cysts are red, pus-filled pimples. They form when plugged follicle walls break deep within the skin.



Topical treatments (applied to the skin) are usually tried first. Some of these are available from the pharmacy without a prescription. If your acne is severe, it may be best to talk with a doctor first. Otherwise, talk with your local pharmacist about which products are best for you.

Topical treatments for acne include:

  • acne face washes/cleansers can be used to reduce the greasiness of the skin. These products may include an antiseptic or antibacterial agent, or mild salicylic acid.
  • benzoyl peroxide (cream, lotion, gel), gets rid of some of the bacteria on the skin and makes the top layer of skin peel off, unblocking the pores. It can help if you have a lot of blackheads but may irritate your skin. If so, use a lower strength or every second night.
  • antibiotic liquids or lotions can help stop infection if you have pus-filled spots. They do not help blackheads or whiteheads. Dab it on once or twice a day over your whole face, not just on the spots. The liquid can be very drying.
  • retinoid gels or creams (eg, tretinoin or Differin), which are mainly for blackheads, make the skin dry and peel. They can be very irritating so only spread a small amount very thinly on your face, no more than once a day. They may make your acne worse at first, but it should improve after a few weeks. Take care in the sun – you may burn more easily, and you should not use them if you are pregnant or there is any likelihood of becoming pregnant.
  • azelaic acid cream, (eg Skinoren, Acnederm) which is put on twice a day. If it irritates your skin, use less or use only once a day.

Treatments take time to work

  • Acne treatments don't do much for existing pimples - their job is to help prevent the next round. Therefore, treatments can take some weeks or months to show an improvement in the acne.
  • Try any new cream or lotion on a small area first, in case of irritation. Then apply to face, shoulders and back (if affected) rather than just the individual spots (follow specific product directions).
  • Stop using lotion/cream if severe irritation develops, and talk to your doctor or pharmacist.
  • If one product doesn’t help, there will be another product or type of treatment you can try. Ask your pharmacist/doctor for advice.
  • Also see ‘Lifestyle measures’ further below.

Treatments for severe acne

See your doctor if your acne doesn’t respond to topical treatments, makes you feel down (depressed) or is severe. Early treatment for severe acne may help prevent scarring.

Treatments may include:

  • oral antibiotics - these may need to be taken for three months or more, depending on the acne. Many antibiotics used for acne cannot be taken in pregnancy (or if you may become pregnant while taking) or given to children under 12 years old.
  • oral retinoids (isotretinoin) - Some family doctors may be able to prescribe isotretinoin, though you may need to be referred to a dermatologist (skin specialist). Isotretinoin may be helpful in treating acne but it also carries a range of possible side effects, some of which can be serious, so its use has to be monitored carefully. It is not suitable for women who are pregnant and women must not become pregnant during this treatment or for one month after treatment (high risk of causing damage to the baby). Your doctor or dermatologist will discuss this treatment further with you.
  • hormone treatments -This may be an option if hormonal imbalance is found.
  • other treatments. Dermatologists may suggest other types of treatments, such as blue-light or other light-based systems.

Self help

Lifestyle measures to help acne include:

  • gentle regular cleaning: avoid excessive scrubbing of the acne/skin
  • leaving acne alone: removing blackheads is not recommended. You should also try not to pick or squeeze pimples - it can make the inflammation worse and cause scarring
  • avoid high humidity, eg, saunas
  • avoid using oily moisturisers/make-up
  • be careful with sun exposure - some treatments make your skin more prone to burn

A low-GI diet may be beneficial

There may not be consensus in the medical field about the effect of diet on acne and it has been thought that no special diets are required. However, some studies have found a reduction in acne lesions in those who follow a low-GI (low Glycaemic Index) diet/.

A low-GI diet:

  • includes foods such as fresh fruit and vegetables, wholegrains, lean meats, seafood are included
  • excludes or keeps to a minimum, processed foods (such as biscuits, cakes, crisps, pastries, lollies)
  • avoids sharp rises and falls in the body’s blood-glucose and insulin levels. This can also help with weight loss, if overweight.

Making changes to dietary habits may not help everyone with acne; talk to your doctor or dietitian for further advice. A balanced diet is recommended for overall good health and nutrition.


Will acne go away?

Acne usually gets better with time, though may take some years to resolve. A few people, however, may have problems into their 30s and 40s, and those with severe acne may be left with some scars (early treatment may help prevent this).

Feeling down

You should try not to let acne lower your self-esteem or make you feel depressed. If you do find yourself feeling very 'down' over this, talk to your doctor or practice nurse. You might also find it helpful to discuss your feelings with a friend. A list of general support organisations which offer phone helplines is given below, under 'Further information and support'.

Clinical Resources

This section will be of most interest to clinicians (eg nurses, doctors, pharmacists and specialists).

The current recommendations state that patients prescribed isotretinoin should have a full blood count, fasting lipids and liver function tests performed before starting isotretinoin and at least once during a 16 to 30 week course of isotretinoin. (4)


  1. How to treat acne - In depth information on current treatments for acne from the NZ Best Practice Journal
  2. Acne (spots) - the essentials Best Health - UK
  3. Acne management - for mild, moderate and severe acne DermNet NZ
  4. Laboratory testing for isotretinoin - BPAC - June 2013

CREDITS: Original material provided by everybody 2012, reviewed by Health Navigator nz April 2014. Images from 

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Last updated on July 17, 2014