title: Letter: Topical vitamin A acid.
mesh_terms: D000287:Administration, Topical; D006801:Humans; D011565:Psoriasis / Q000188:drug therapy*; D014212:Tretinoin / Q000008:administration & dosage* / Q000627:therapeutic use; D014801:Vitamin A / Q000031:analogs & derivatives*
chemical_list: D014801:Vitamin A; D014212:Tretinoin