Benzoyl peroxide attacks the P. acnes bacteria. However, one of its main side effects is dryness: If you’re going to use anything with benzoyl peroxide, make sure to moisturize afterwards. Sulfur and azelaic acid are less common and less severe alternatives to benzoyl peroxide. Dr. Peter Lio, assistant professor of clinical dermatology at Northwestern University, says sulfur-based treatments are “a good fit for patients who can’t tolerate the side effects of benzoyl peroxide.”
Topical antibiotics deemed safe during pregnancy include clindamycin, erythromycin, and metronidazole (all category B), due to negligible systemic absorption. Nadifloxacin and dapsone (category C) are other topical antibiotics that may be used to treat acne in pregnant women, but have received less study. No adverse fetal events have been reported from the topical use of dapsone. If retinoids are used there is a high risk of abnormalities occurring in the developing fetus; women of childbearing age are therefore required to use effective birth control if retinoids are used to treat acne. Oral antibiotics deemed safe for pregnancy (all category B) include azithromycin, cephalosporins, and penicillins. Tetracyclines (category D) are contraindicated during pregnancy as they are known to deposit in developing fetal teeth, resulting in yellow discoloration and thinned tooth enamel. Their use during pregnancy has been associated with development of acute fatty liver of pregnancy and is further avoided for this reason.
Any acne treatment is a weeks-long experiment that you’re conducting with your skin. Acne is slow to heal, and in some cases, it can get worse before it gets better (nearly every benzoyl peroxide product we looked at emphasized the likeliness of irritating acne further, and starting off with a lighter application). April W. Armstrong, a doctor at the University of California Davis Health System, recommends waiting at least one month before you deem a product ineffective.
Scars (permanent): People who get acne cysts and nodules often see scars when the acne clears. You can prevent these scars. Be sure to see a dermatologist for treatment if you get acne early — between 8 and 12 years old. If someone in your family had acne cysts and nodules, you also should see a dermatologist if you get acne. Treating acne before cysts and nodules appear can prevent scars.