Thanks for query.
There should be some allergen causing this rash
It may be from internal side like having worms infestation or external allergen like soap,duo
spray,clothes or taking some eatables items.
Try to identify the allergen and avoid it.
See that have you started wearing new clothes,synthetic clothes or changed the soap,duo or lotion etc.
Go for anti worm tablet like dewormin or Alminth
once in a week for 42 weeks.
Ok and bye.