The appearance of a round skin rash, consider the coin-shaped eczema, lichen planus, ringworm and other diseases. 1. coin-shaped eczema: this is a special type of eczema, and drug stimulation, mental factors, alcohol and long-term use of soap, etc., also called discoid eczema, lesions usually occur in the limbs, mainly manifested as erythema, pimples, pimples or blisters, etc., and there will be obvious itching. 2. lichen planus: lichen planus is a fungal infection caused by malassezia invading the cuticle of the skin, mainly in the pores as the center, the border is clear rash, the beginning of the time is a point-like rash, with the development of the disease will appear flaky rash, the surface is covered with scales, and accompanied by a slight itching. 3. Ringworm: ringworm is a common fungal infection, caused by fungal colonization of the skin, more common in the groin, perineum, anus and buttocks and other parts of the body, mainly ring or semi-circular lesions, usually accompanied by intense itching. A circular skin rash, should go to the hospital for a detailed examination, for the cause of the symptomatic treatment, usually pay attention to keep the skin clean and hygienic, do not scratch.