I think it's due to dryness ..so plz apply oil like coconut oil or almond oil.n see it should work .<br>

May be due to sweat.. can apply coconut oil mixed with equal quantity of castor oil.. if still there then always good to consult the paed...

It's like fungal infection due to sweat...please apply coconut oil+neem paste...and give him a bath with few drops of neem paste in water...as it doesn't go then visit your doctor