Acne is often considered by GPs to be a minor affliction. Most patients with the condition rely on OTC remedies and only a small proportion of those affected by acne consult their GP about it.
However, patients with acne often suffer from poor self-image, and because it commonly affects teenagers this can result in impaired social development. Fortunately there are many effective treatments.
Causes of acne
Acne develops when the normal drainage of sebum from the sebaceous glands to the skin surface is blocked.
The blockage usually consists of a mixture of hair, sebum and dead skin cells shed by the lining of the follicle.
This mixture of oil and dead cells allows the bacteria Propionibacterium acnes that live on the surface of the skin to grow in the plugged hair follicles.
These bacteria produce chemicals that attract white blood cells and cause inflammation.
When the wall of the plugged follicle breaks down the sebum, shed skin cells and bacteria are spilled into the nearby skin, leading to lesions or pimples.
Patients with acne frequently have a variety of lesion types. The basic acne lesion, called the comedone, is an enlarged and plugged hair follicle.
If the comedone stays beneath the surface of the skin, it is called a closed comedone and produces a white bump called a whitehead.
A comedone that reaches the surface of the skin and opens up is called an open comedone or blackhead, because it looks black on the skin's surface.
This black discoloration is caused by changes in sebum as it is exposed to air. Other acne lesions that can develop include papules, pustules, nodules and cysts (see box).
There are a number of factors that can contribute to the development of acne or worsen pre-existing acne.
Hormone changes at puberty, in pregnancy or as a result of taking the oral contraceptive Pill can increase the production of sebum. This increases the likelihood of developing acne.
Oil from skin products such as moisturisers or cosmetics, or grease encountered in the work environment can also cause skin pores to become blocked.
Environmental irritants such as pollution and high humidity can worsen acne.
Squeezing or picking at blemishes, hard scrubbing of the skin and stress are also aggravating factors.
There are many treatments for acne, and the majority of patients can expect to have good symptom control in primary care.
Most patients' acne will respond to simple treatment with topical retinoids combined with antibiotics.
In rare cases, three treatments are needed (see box right).
Patients should be warned that it takes time for acne products to begin working. As a rule of thumb, it takes six to eight weeks before the patient will begin to see an improvement.
Hormonal treatments are useful in women. Most women with acne have normal hormone levels but those who fail to respond to usual treatment regimens should have their hormonal status checked.
If testosterone levels are raised they can be managed with oral contraception, the anti-androgen cyproterone acetate (as co-cyprindiol) or spironolactone.
Isotretinoin is effective for the treatment of severe nodular acne and severe acne unresponsive to other treatments but needs specialist initiation and careful follow-up.
Pre-treatment tests include liver function tests and a FBC. Women also need to have two negative pregnancy tests since isotretinoin is highly teratogenic. These tests need to be repeated after one month of treatment.
Common side-effects include dry skin, hyperlipidaemia and an initial acne flare-up. Uncommonly, it can also cause alopecia, myalgia and visual defects.
It has also been suggested that isotretinoin may be linked to an increased risk of depression and suicide, but there is insufficient evidence to confirm this link.
It is important that patients with acne understand that the condition is not caused by poor diet or lack of cleanliness.
Any medical treatments given should be supported by advice on self-care.
Patients should be advised not to pick at acne. This can make it worse by spreading inflammation. Gentle washing of the face twice a day with a mild cleanser and patting it dry is advised.
Acne is not caused by poor hygiene, and vigorous washing and scrubbing will not clear the skin. In fact, scrubbing can irritate skin and make acne worse. The way to clear acne is with appropriate acne products.
Patients should also be advised to use a minimum of cosmetics. Skin creams and make-up increase the chances that the pores will become blocked. Hair that falls over the face and greasy hair products should also be avoided.
Dr Merriman is a GP in Oxford.
|Types of acne lesions|
|Treatments for acne|
Mild papulopustular acne
Severe papulopustular or nodular acne