Hello. Thank you for writing to us at healthcaremagic I suggest a possibility of Fungal infection. This is not related to thyroid nodules. 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 in hot and humid weather of summers. 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. 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. Oral antifungal e.g fluconazole or terbinafine would be useful for faster symptomatic relief and faster clearance. An OTC oral antihistamine e.g cetrizine 10 mg once daily will provide you symptomatic relief from itching. Regards