its allergy..
both my nieces also have this and keep scratching..
they went to a doc in Johor specialised in allergy/eczema..
depending on the seriousness of the allergy/eczema, they need to stop eating certain food..
one stop eggs, one stop sugary food... on top of that, certain medicine to eat as well..
both of them recovered a lot but will need to balance out for a year before it clears off 100%..