Itchy red bumps in summer may be caused by sweat rash, insect bite dermatitis, folliculitis and other reasons. 1. Sweat rash: summer due to the sultry temperature, a large amount of sweat is not easy to evaporate, infiltration of the skin to make it swollen, resulting in narrowing or blocking of the sweat ducts, thus triggering sweat rash, which is mainly manifested in the skin with elevated pimples, blisters, or herpes papules, and may be accompanied by tingling or itchiness in some patients. 2. Insect bite dermatitis: In summer, due to the mosquitoes, after being bitten by mosquitoes, it is possible for the skin to have an allergic reaction, thus triggering insect bite dermatitis, which is manifested as solid pimples, redness, swelling, erythema, blisters and other symptoms of the skin at the place of the bite, accompanied by intense itching symptoms. 3. Folliculitis: poor personal hygiene, sweating, unhygienic swimming pools and other triggers, easy to lead to bacteria, fungi and other pathogens caused by follicle infections, often manifested in the formation of red papules around the follicle, accompanied by red, swollen, hot, painful inflammatory reaction, can be accompanied by itching, pain and other discomforts, the severe cases can also be pus, ulceration and so on. Summer itchy red bumps may also have other causes (such as eczema, etc.), it is recommended to go to the hospital in a timely manner to improve the examination, to give targeted treatment after the cause is clear, do not self-medication.