It can be because of
dermatitis/
eczema or
allergy or dryness or
fungal infection or psoaiasis etc. I need details of case n preferably pics of affected area. In the meanwhile follow this
moisturize frequently.
Avoid sudden changes in temperature or humidity.
Avoid
sweating or overheating.
Reduce stress.
Avoid scratchy materials, such as wool directly in contact with skin.
Avoid harsh soaps, detergents, and solvents.
Be aware of any foods that may cause an outbreak and avoid those foods.
For this homeopathic treatment is very effective
for more details you can consult me.