Hello. Thank you for writing to us at healthcaremagic
I suggest a possibility of Tinea/
Fungal infection.
The anatomy of body folds is such that it provides an ideal environment for fungus to proliferate because of moisture and humidity that prevails in body folds, specially more in hot and humid weather of summers.
Being overweight adds to the predisposition.
A KOH wet preparation made by scraping a small amount of scale from the surface of skin lesions to look for fungal elements (hyphae) would confirm the diagnosis.
Topical steroids should be avoided because apart from providing symptomatic relief from itching they would rather help fungus proliferate by decreasing the local immunity.
I would suggest a
topical antifungal cream, twice daily for 4-6 weeks.
An OTC antifungal e.g
clotrimazole 1% cream can be used twice daily Or one of the prescription antifungals e.g
sertaconazole, luliconazole Or bifonazole may also be used.
Since you have an extensive involvement of multiple body folds therefore an
Oral antifungal e.g fluconazole or terbinafine would be useful for early symptomatic relief and faster clearance.
An OTC oral antihistamine e.g cetrizine 10 mg once daily will provide you symptomatic relief from itching.
Regards