Ringworm is a fungal infection, and steroid-based creams (such as Cosvate GM) may temporarily reduce itching but can worsen or mask the infection and cause skin colour changes. It is better to avoid Cosvate GM and use a topical antifungal (such as clotrimazole or terbinafine) for at least 2 to 4 weeks, applied consistently. Oral itraconazole (like Itrasys) may be needed in stubborn or widespread cases, but should only be started and correctly dosed by your dermatologist, and seven days may be insufficient. It is best to confirm the treatment plan with your dermatologist before starting or changing medicines.