Hot weather back itchy red rash may be eczema, prickly heat, tinea corporis, etc., patients should consult a doctor in a timely manner to clarify the cause of the disease and then carry out the appropriate treatment. 1. Eczema: a chronic inflammatory skin disease caused by a variety of internal and external factors, which can lead to the appearance of erythema, papules, oozing, vesicles, erythema and other polymorphic skin lesions on the back. 2. prickly heat: when the weather is hot, the temperature and humidity are relatively high, if there is an itchy, densely arranged pinpoint-sized pimples and papules on the back, it should be considered to be prickly heat caused by the narrowing or blocking of sweat ducts, and sweat stagnation in the sweat ducts. 3. Ringworm: associated with fungal infection, summer heat and humidity, conducive to fungal reproduction, easy to induce ringworm. Ring-like skin lesions may appear, accompanied by papules, papules, scales, itching and other manifestations. There are many other causes of itchy red rashes on the back, and it is recommended to consult a doctor in time for a clear diagnosis.