Azelaic acid is a naturally occurring, straight-chain dicarboxylic
acid which is effective in the treatment of
rosacea, presumably on account of its anti-inflammatory properties. In randomized, double-blind, multicenter studies involving patients with moderate papulopustular facial
rosacea, twice-daily topical application of
azelaic acid 15% gel to the face was significantly more effective than twice-daily administration of either its vehicle (two studies) or
metronidazole 0.75% gel (one study) in reducing inflammatory lesion counts and
erythema severity. However, neither active treatment had a clinically discernable effect on
telangiectasia. In all three studies,
azelaic acid 15% gel recipients experienced continuous decreases in lesion counts and
erythema throughout the 12- to 15-week treatment periods. However, the effects of
metronidazole 0.75% gel plateauxed after 8 weeks. In other efficacy assessments in these studies,
azelaic acid 15% gel was superior to its vehicle and
metronidazole 0.75% gel in both the investigators' global assessment of
rosacea and the investigators' end-of-study evaluation of overall improvement, and superior to its vehicle in the patients' end-of-study evaluation of overall improvement. The most frequent treatment-related cutaneous adverse events during administration of
azelaic acid 15% gel include burning/stinging/tingling and
pruritus (
itching); however, these events are predominantly transient in nature and mild-to-moderate in intensity.