Itchy rings and rashes are often due to a fungal infection (like ringworm or tinea). Treatment usually involves antifungal creams or ointments applied to the affected area for 2 to 4 weeks. Keep the skin clean, dry, and avoid tight clothing, and wash clothes and bedding regularly. If the infection does not improve or spreads, see a doctor, who may prescribe stronger topical or oral antifungal medicines.