Hello and welcome to healthcaremagic
I am Dr. Kakkar. I have gone through your query and I have understood it. I have also reviewed the pictures.
This seems to be a case of fungal infection(Tinea corporis
and Tinea cruris
); well defined red, circular patches. Sweating, heat and humidity are the factors which encourage fungal growth.
If I was the treating doctor I would have asked you to use a topical antifungal
cream e.g clotrimazole
1% cream twice daily for 2-4 weeks.
An oral antifungal
e.g fluconazole 150 mg tablet, once every week, for 4 weeks is also advisable.
An OTC antihistamine e.g cetrizine 10 mg once daily would provide you symptomatic relief from itching.