
A group of medications for normalizing the follicle cell lifecycle are topical retinoids such as tretinoin (brand name
Retin-A), adapalene (brand name Differin), and tazarotene (brand name Tazorac). Like isotretinoin, they are related to vitamin A, but they are administered as topicals and generally have much milder side effects. They can, however, cause significant irritation of the skin.
ref:http://en.wikipedia.