Hello mr. Prasad
The rashes are usually taken as allergic manifestation. In ayurveda the usual treatment for such condition is taken on two flanks, first is blood purifiers and other is immuno boosters. Many a times this allergy
can be from intrinsic reasons also. Get stool test
done if worms are there then have some wormicide first. Haridra khand and mahamanjishtha arisht will cure it.