Small blisters on the arm is very itchy consider papular urticaria, acute contact dermatitis, acute eczema, etc., the main treatment is drug therapy, according to the specific cause of the selection of appropriate drugs. 1. papular urticaria: most of them are caused by bites of bedbugs, mosquitoes, fleas, lice, mites, etc., and a few are related to food allergies. You can apply glycerine lotion, compound beclomethasone camphor cream, etc., and for those with severe symptoms, you can take diclofenac tartaridine and diphenhydramine orally. 2. Acute contact dermatitis: If the arm area comes into contact with irritating substances, such as strong acid or alkali, an acute inflammatory reaction will occur, with small blisters appearing, which should be rinsed with saline or flowing water, and localized hydrocortisone cream and trimethoprim cream should be applied, and oral ipecac or ibogaine can be used if the itching is severe. 3. Acute eczema: acute eczema is a bad lifestyle and environmental factors, mental factors caused by inflammatory skin diseases, if there is no ooze or oozing is not much, you can apply glycerine lotion, mometasone furoate cream, if oozing is more you can choose the boric acid solution and isacridine solution wet compresses, itching serious can be taken orally cyproheptadine, sitelizine. Itchy small blisters on the arm, there may be other reasons, it is recommended to go to the hospital for a detailed examination, to clarify the cause of the standardized treatment, the above drugs should be used in accordance with the doctor’s instructions.