i have quite similar problem too; my skin gets itchy only if i ate food that triggers the rash
Hello,
Although it is difficult to confirm the diagnosis without examination but the symptoms can be due to fungal infection or tinea cruris. Wash your groin daily and then dry thoroughly by pat drying, not rubbing. A hairdryer is useful if you have hairy groins. The damp groin is an ideal site for fungi to multiply. Also wear cotton underwear and change them twice a day and do not share other people’s towels.Application of local antifungal cream(terbinafine, clotrimazole, econazole, ketoconazole, miconazole) and oral antifungal drugs are the mainstay of treatment. If the symptoms persist then a dermatologist’s evaluation will be the best.
I hope it helps. Take care and please do keep me posted on how you are doing or if you have any additional queries. Kind regards.