Not being a practitioner of ayurveda I am not sure what is available. But there are many over the counter remedies, lotions and salves that can relieve the itching. It very well could be an allergic reaction to the type of soap you use to wash your clothes with. Or even the soap you bathe with.

Try something like Cortaid, then also switch your soaps. When washing your clothes run them twice through the rinse cycle to be sure all the soap residue is removed. When bathing make sure you rinse and dry the problem area well.

Good luck and best wishes! 

You may also want to wear boxers instead of briefs to also help relieve the irritation.