Itchy red patches on the skin may be caused by ringworm, insect bite dermatitis, eczema and other causes. 1. Ringworm: ringworm is a skin disease caused by fungal infections such as dermatophytes, mainly manifested as red spots, pimples and blisters on the skin surface, accompanied by peeling and itching. 2. Insect bite dermatitis: insect bite dermatitis is an allergic reaction to insect bites, which is characterized by red patches and blisters on the surface of the skin, accompanied by intense itching. 3. Eczema: Eczema may be related to endocrine diseases, exposure to allergens, immune abnormalities and other factors, manifested as red patches on the surface of the skin, papules, mossy changes, accompanied by intense itching. Red itchy skin may also have other causes, it is recommended to go to the hospital in a timely manner to improve the examination, to clarify the cause of the disease to give targeted treatment.