Itchy small pimples may be caused by folliculitis, eczema, insect bite dermatitis and other diseases. 1. Folliculitis: If the hair follicles and skin are damaged and then infected by bacteria, folliculitis is easy to cause, commonly due to Staphylococcus aureus. Common risk factors include decreased body immunity, obesity, etc. Folliculitis can occur in any number of different locations, and some patients will develop folliculitis in the form of itchy, painful red pimples. 3. Eczema: the cause of this disease is not clear, may be related to genetics, immune abnormalities, hormone level disorders, contact with allergens, mental stress and other factors, the common symptom is the appearance of skin pimples, blisters, can be accompanied by itching, scaling and other symptoms, can be manifested as itchy small pox on the body. 2. Insect bite dermatitis: Mosquito bites usually show up as one or a few obvious red pimples on the body, and the more you scratch, the more itchy it is called insect bite dermatitis. Bites usually appear on exposed skin, such as arms, shoulders, neck and face. They also cause an itchy red rash in sensitive people. 4. Other: In addition to this, you need to consider that it is caused by scabies, infectious molluscum contagiosum, contact dermatitis and other diseases. It is recommended that patients with itchy small pimples on the body go to the hospital to improve the relevant examination to clarify the specific cause.