Hi Welcome to the MedHelp forum!
Itchy localized rash can be due to allergic dermatitis, eczema, contact dermatitis, shingles, psoriasis, fungal infection like or Tinea corporis. It is difficult to comment beyond this at this stage without examining the rash. Please consult a skin specialist. There are high chances of fungal infection.
Hope this helps. Please let me know if there is any thing else and do keep me posted. Take care!
Is there any sores in your mouth? it could be hand foot and mouth disease. my brother got that from some kind of parasite on a beach one summer! you should get it looked at!