<prompt> Topical azelaic acid is used in -Hyperpigmentary disordersDermatophvte infectionsVitiligoMixed infections  <response>: Topical azelic acid is used in treatment of melasma a hyper pigmentation disorder. azeliac acid is a competitive tyrosinase inhibitor that inhibit the synthesis of melanin. It is used as 10-20 cream and is as efficacious as hydroquinone. IADVL textbook of dermatology , pigmentary disorders page 750 