For ringworm on the back, topical miconazole nitrate cream or terbinafine cream can be applied topically if the ringworm is caused by a fungal infection.1 If the infection is heavy and accompanied by significant flaking and dryness, you can also apply mucopolysaccharide polysulfate cream or urea cream, alternating between the two, topically as appropriate. At the same time, you need to take oral antihistamines, such as oral loratadine or epalrestin. If the infection is heavy, oral antifungal medication is also needed, such as oral itraconazole or terbinafine.2. If the lichen planus is caused by Malassezia infection, topical application of terbinafine cream and oral ketoconazole can also be used for antifungal effects. You also need to pay attention to local cleanliness and try not to use alkaline toiletries, and you can use sulfur soap for external washing as appropriate.