Diabetic patients with red skin bumps itchy need to look for the cause, may be caused by diabetes resulting in capillary lesions, may also be caused by allergic factors. 1. capillary lesions: diabetic patients with glycoprotein deposition in the capillary basement membrane, affecting the capillary structure, resulting in thickening of the tube wall, tissue hypoxia leading to small capillary lesions caused by diabetic dermatosis, such as redness and itching, red bumps and so on. 2. Allergic factors: itchy red bumps on the skin are not necessarily caused by diabetes, but may also be caused by contact with allergens, and may be caused by mosquito bites and other reasons. Patients should do allergen testing and blood sugar check. Diabetic patients with itchy red bumps need to actively seek medical attention, patients should not self-medication, to avoid aggravating the condition.