Grading of acne severity and treatment
First line treatments
- Topical retinoids, the first line treatment for mild acne, have comedolytic, anti-comedogenic, and anti-inflammatory effects and are good in early and established acne and as maintenance therapy. The most common side effects are dryness and irritation, which can be avoided by application on alternate days initially. In theory retinoids are teratogenic, so women should be advised about this.
- An alternative to topical retinoids is benzoyl peroxide. It is highly effective at reducing antibiotic sensitive and resistant propionibacterium acnes so is good for inflammatory acne and is more effective than topical antibiotics. It has mild comedolytic activity but no anti-comedogenic action. It can cause dryness and irritation, so start with a low strength cream formulation and titrate up. Advise that it can bleach clothes.
- Topical antibiotics are also helpful in mild to moderate inflammatory acne but should be used as combination formulations with benzoyl peroxide to help reduce the risk of bacterial resistance.
Second line treatments
- Topical azelaic acid 20% works in a similar way to benzoyl peroxide and retinoids but is less irritating. It is likely to be much less effective than retinoids and benzoyl peroxide but is helpful in patients with post-inflammatory pigmentation.
- For moderate acne a generic tetracycline (but not minocycline, because of the risk of skin pigmentation and other more serious adverse effects) is recommended for at least six weeks, in combination with topical treatment. Combining an oral antibiotic with benzoyl peroxide helps to reduce the risk of bacterial resistance. Advise female patients that tetracyclines are contraindicated in pregnancy and that they should take adequate measures to avoid conceiving. Tetracyclines should not be prescribed to children aged under 12 years, because of potential staining of teeth enamel.
- Hormonal treatment may improve acne in some women. There is little evidence that any is better than the others. Given the potential for adverse effects, particularly venous thromboembolism (VTE), you should consider the risk-benefit ratio when prescribing hormonal treatment. Any hormonal treatment is contraindicated in women with focal migraine or a higher than normal risk of VTE. Co-cyprindiol has a product licence for severe acne and can improve acne in up to 90% of female patients. Because of concerns about the risk of VTE, the advice is that this be given for 3-4 cycles after the acne is completely resolved then withdrawn (repeat courses may be given for recurrence). However, a recent paper by S Franks and colleagues (see Further Reading) has shown that this is not necessary, as there is no good evidence to confirm an increased VTE risk, and there are moves to change this recommendation.
- Consider referral if the above described treatments do not result in the desired outcomes (see box).