Azelaic acid is recommended as a useful second line or adjunctive treatment for mild to moderate severity acne. It is anti-inflammatory and antibacterial and also works actively against comedones. Azelaic acid is particularly useful where there is post-inflammatory hyperpigmentation because of its lightening effect, and may be better tolerated than tretinoin.[1][2][3]

A clinical trial in Leeds, UK, matched 20 pairs of patients to 20% azelaic acid against its base, applied twice daily. They found a significant reduction in inflamed and non-inflamed lesion count compared to placebo. Azelaic acid was also shown to reduce the density of the bacterium species propionibacterium[4].

In a trial of 289 patients with comedonal acne, azelaic acid was equally as effective as tretinoin at reducing the number of comedones, but was tolerated better than tretinoin, causing fewer local side effects[1]

In one study, 55 women with adult acne (18-45) were received either azelaic acid or adapalene gel. Treatment with Azelaic acid was found to be non-inferior (within 50% margins) compared to adapalene gel, but dryness and scaling were not as severe as the adapalene group[5].

Azelaic acid has been shown to be a good option for patients with mild-to-moderate acne, associated with moderate-to-severe post inflammatory hyperpigmentation, as it has been shown to reduce both the acne and the post-inflammatory hyperpigmentation[6].