The causes of itchy body in 90-year-old people include allergy, combined internal diseases and dry skin. 1. Allergy: some people will be allergic to certain substances after contact, the patient will appear all over the body itching, and may be accompanied by red rashes, this part of the patient can be treated with oral antihistamines and apply dexamethasone cream, commonly used antihistamines are loratadine, cetirizine and so on. 2. Combined visceral diseases: some patients with liver disease, diabetes and kidney disease will have symptoms of generalized itching. 3. Dry skin: the elderly sebaceous glands atrophy, more likely to have dry skin than young people, especially in the winter, prone to pruritus resulting in itching. 90 year olds itchy body need to be in the hospital dermatology department, the above drugs need to be used in accordance with the doctor’s instructions.