Hello. Thank you for writing to us I would like to keep a possibility of Tinea/ fungal infection. Buttocks and groin area is particularly predisposed to fungal infections. Heat and sweaty conditions are conducive to fungal growth. Fungal infections are usually itchy as well as scaly, patches of expanding skin lesions with peripheral raised rim and central clearing. KOH wet preparation made by scraping a small amount of scale can be examined under the microscope to look for fungal elements. I would suggest you to try an OTC topical antifungal e.g clotrimazole 1% cream, twice daily for a few days. An OTC oral antihistamine e.g cetrizine 10 mg once daily will provide you symptomatic relief from itching. Regards