You haven't given much information. There are many diagnosis that it could be. Anything from a burrowing bug (scabies), to allergic reaction, to bacterial dermal infection, to fungal dermal infection and others. I suggest you look at images on line of impetigo, scabies, allergies, dermal fungal infections etc. Is it dry and scaly? Tiny fluid filled bumps? Large fluid filled bubbles? Give more information. Could be impetigo, exzema, allergy, staph, a reaction to chemical exposure etc.
Are you just itching or do you have any spots/rash that you can see?