Hi...thanks for posting here.Itchy rash
with central clearing and periphery spreading is suggestive of fungal infection
.It always occurs where there is moist environment like groins,inner part of belly.Try to keep area as dry as possible,Use loose clothings,take antiallegic tablets at night ,apply zimig cream at night for 2 weeks, still it persists then you better consult a dermatologist
and start oral medications.You can apply candid
soap for wash at day time.