Red bumps on the back can be caused by mosquito bites, folliculitis and other diseases, or acne, it is recommended to go to the hospital as soon as possible to find out the cause. 1. Insect bite dermatitis: Insect bite dermatitis can appear as a symptom of red bumps on the back. Insect bite dermatitis, also known as papular urticaria, is a localized skin allergic and inflammatory reaction that occurs after the skin is bitten by an insect, often manifested as a sudden appearance of the skin of the body, often accompanied by itchy red spots. 2. Folliculitis: Folliculitis can appear as a symptom of many red spots and bumps on the back. Folliculitis is a common inflammatory skin disease of the hair follicle, can occur in any hair follicle part of the body, often manifested as red papules around the hair follicle, can be accompanied by itching, pain, and even pus and other symptoms. The cause is related to infections such as Staphylococcus aureus and Malassezia. 3. Acne: Acne is a common chronic inflammatory disease of the sebaceous glands of the hair follicles, associated with heredity, sebum secretion, keratinization of the sebaceous gland ducts of the hair follicles and propagation of Propionibacterium acnes, etc. This disease can also lead to the symptoms of red dots and bumps on the back of the patient. In addition to the above factors, red dots and bumps on the back may also be caused by other diseases. If the symptoms continue to remain unrelieved, it is recommended to seek medical advice as soon as possible, and go to a regular hospital to find out the cause of the problem and for further treatment.