Suggest Treatment For Hard Skin Patch On My Ankle

hi, i've got a dark very tough skinned patch on my left ankle, no where else... it rarely itches but it is always dry and scaly hard like a very very dry elbow... i've tried every kind of oil and lotion... gets less when i go to hot climates and worst in cold dry... what can i do to get rid of it or lessen it (am in cold climate now).