If there is no rash on the arm, consider itching due to dry skin from sun exposure. Topical application of a mild, non-irritating moisturizing cream solution 2-3 times a day can provide gradual relief and avoid excessive washing. If accompanied by a rash considered to be due to allergies caused by dermatitis, eczema or ultraviolet radiation caused by solar dermatitis, you can use glucocorticoid cream for treatment, such as mometasone furoate cream, morning and evening once a small amount of external application. It should be noted that if the rash has exudation, local saline wet compresses need to be applied first, and the exudation improves before using cream treatment. If the rash occurs on the wrist, itches at night and is contagious, attention needs to be paid to exclude scabies, which can be treated with sulfur cream.