After starting topical tretinoin for acne vulgaris, the patient reports that her acne is worse. Should she immediately discontinue the drug?

No. While many textbooks state that acne vulgaris may flare during initiation of topical treatment; current evidence suggests that this most likely represents normal fluctuation in the intensity of disease. Patients should not discontinue therapy and should understand that beneficial effects may not be seen for 6 weeks. Maximum improvement may take up to 6 months or more with continued therapy. The most common reasons for tretinoin failures are failure of the health care provider to instruct patients thoroughly about proper application and failure to provide an accurate assessment about expected results. Patients often discontinue therapy after failing to see improvement during the first month.

Yentzer BA, McClain RW, Feldman SR: Do topical retinoids cause acne to “flare”? J Drugs Dermatol 8:799–801, 2009.