Itchy bumps on the back are considered to be caused by folliculitis, papular urticaria, nodular itchy rash and other diseases. 1. Folliculitis: often manifested as red papules centered on hair follicles, accompanied by itching or pain, can be seen in all parts of the body. The cause is mainly due to bacteria, fungi and other pathogens infected hair follicles, trauma, wearing tight clothing, sweating and other factors can also trigger folliculitis. 2. Pimple urticaria: Pimple urticaria is an allergic dermatosis caused by insect bites, which occurs in exposed areas, such as the head, face, hands and feet, waist and back, etc. Localized pimples will appear, accompanied by itching and other symptoms. 3. nodular itchy rash: nodular itchy rash with itching, nodules as the main feature, the cause is not yet clear, some patients are the onset of mosquito bites, but also with gastrointestinal dysfunction and endocrine disorders have a certain relationship. Causes of itchy back with small bumps of more reasons, it is recommended that patients seek medical examination to clarify the cause of the disease.