Hello,
Without examination,it is very difficult to confirm a diagnosis,but it can be due to
heat rash,contact dermatitis to socks or shoes,rashes due to friction rub, sweat dermatitis, fungal infections,nummular eczema or venous indsufficiency.
Oral antihistaminics like benadryl or claritin,oral steroids and topical application of steroids and calamine are the minstay of treatment.If the itchy rashes still persist then consultation of a dermatologist will be the best.
Hope it helps.