This leads to an accumulation of the skins natural oils and bacteria (Propionibacterium acnes) in the skin (which feed on the oils and keratin) which further inflame the gland causing acne.
Common causes of drug-related cheilitis include Etretinate, Indinavir, Protease inhibitors, Vitamin A and Isotretinoin (a retinoid drug).
Isotretinoin (13-cis-retinoic-acid; brand name Roaccutane), which is often used to treat severe acne, is such a strong teratogen that just a single dose taken by a pregnant woman may result in serious birth defects.
Patients on Retin-A, Renova, Differin or isotretinoin have been advised by doctors not to have waxing performed; these medications can weaken the skin, and lead to tearing of the skin.