Antibiotics for acne
Antibiotics are commonly used to treat acne. They are available as topical preparations for mild acne, and as tablets, capsules and elixirs for oral use in moderate and severe acne.
A doctor’s prescription is required to obtain antibiotics. The antibiotics listed on this page were available in New Zealand in April 2014. Other antibiotics or brand names are available on prescription in other countries.
Mechanism of action of antibiotics in acne
Antibiotics have two main effects in acne:
- They reduce the number of bacteria on the skin surface and in the follicles, including Propionibacterium acnes
- They have an anti-inflammatory action
- Topical antibiotics in acne
- Topical antibiotics require a prescription in New Zealand.
- Clindamycin – ClindaTech solution, Topicil solution and Duac Once Daily gel
- Erythromycin – Eryacne gel
Side effects and risks of topical antibiotics
Dryness of the treated area is usually mild but is a common side effect of topical antibiotics. If the skin is visibly scaly, apply a light non-oily moisturiser.
Skin irritation from topical antibiotics is rarely severe. Occasionally, irritation means that the patient should stop using the product. Lotions are less likely to cause irritation than solutions or gels.
Contact dermatitis (red, dry, itchy skin) can be due to irritancy or allergy. It can be treated with a topical corticosteroid such as hydrocortisone cream (available at a NZ pharmacy without prescription).
Bacterial resistance to antibiotics most frequently arises with intermittent use of topical antibiotics. To reduce the chance of bacterial resistance, apply topical antibiotics liberally twice daily and also use benzoyl peroxide and/or a topical retinoid.
Side effects and risks of oral antibiotics (see also, DermNet’s page on tetracycline)
Allergy – oral antibiotics can cause a variety of rashes in those susceptible. These can be mild or life-threateningly severe. Allergy to a tetracycline or to erythromycin is very uncommon, but more than 2% of those on trimethoprim or cotrimoxazole become allergic to it. Tell your doctor if you have ever reacted badly to an antibiotic.
Photosensitivity may be a problem for those taking doxycycline. Taking the medicine after the evening meal reduces the risk of sunburn. Dress up and protect your skin from exposure to the sun.
Gastrointestinal disturbance affects about 5% of patients and includes nausea, colicky pain and diarrhoea.
Thrush (Candida albicans infection) affects 5% of treated women and most often affects the vagina. Thrush can also affect the oral mucosa or body folds (intertrigo), particularly in diabetics or in obesity. Thrush is less likely with erythromycin than with tetracycline.
Bacterial resistance may occur but is less common with the use of oral antibiotics than with topical antibiotics.
Acne antibiotics are unlikely to result in failure of the oral contraceptive pill but if you are concerned, add a barrier method and talk to your doctor about your risks.
Antibiotics and how they work in acne
Antibiotics work by killing germs (bacteria) that contribute to the cause of acne. They also have a direct effect of reducing inflammation. Antibiotics usually work well to clear inflamed acne spots and any surrounding skin inflammation.
However, they have little effect on unplugging blocked pores – which you can see as blackheads and whiteheads (comedones). So, if you only have mild acne with just blackheads and whiteheads, you are better off using a rub-on (topical) treatment that unblocks holes in the skin (pores). If you have a lot of blackheads and whiteheads as well as inflamed acne spots, you may be advised to use a topical treatment such as benzoyl peroxide in addition to taking an antibiotic tablet.
Always read the leaflet that is in the packet of antibiotics. Things such as precautions and possible side-effects vary between antibiotics. The following are some general points.
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