The difference between high blood sugar itch and allergic itch lies in the etiology, clinical manifestations, treatment methods and other aspects. 1. Etiology: high blood sugar itchy skin is mainly considered to be caused by diabetes mellitus, usually diabetic patients with immune dysfunction, elevated blood glucose levels, thus causing itchy skin. Some patients can also be due to diabetic peripheral neuropathy and sensory abnormalities, which is manifested as itchy skin. For allergy-induced itching, it is mainly related to the patient’s exposure to allergens. 2. Clinical manifestations: high blood sugar itchy skin may be manifested as symmetrical numbness of the distal limbs, ants and other unusual sensations, but also easy to accompany the spontaneous burning pain, lightning-like pain, cold skin, hyperpigmentation and other symptoms. Itchy skin caused by allergy can be manifested as erythema, papules, blisters, swelling, etc., and is also easily accompanied by other symptoms such as dyspnea, tearing, tachycardia, and so on. 3. Treatment: If high blood sugar and itchy skin are caused by diabetes mellitus, vitamin B1 and other nutritive nerve drugs, and metformin, insulin and other hypoglycemic drugs can be used as prescribed by the doctor. For clear allergies caused by itchy skin, you can first use running water to clean or ice packs on the skin, or follow the doctor’s instructions with benadryl, loratadine and other antihistamines or glucocorticosteroid treatment. It is recommended that people with itchy skin consult a doctor for examination in order to identify the cause of the disease and then follow the doctor’s instructions for treatment, so as to improve the discomfort and quality of life.