Arm skin blisters (i.e. blisters) with itching are associated with many diseases, common diseases such as chickenpox, eczema, contact dermatitis and so on. 1. Chickenpox: Chickenpox is usually a contagious disease caused by infection with varicella zoster virus, which may appear on the whole body with erythematous spots, papules, blisters, scabs, which may be accompanied by fever, itching and other symptoms, and therefore the symptoms of blisters with itching on the arm skin will appear. 2. Eczema: the cause of this disease is not known, it is a kind of inflammatory skin disease caused by internal and external factors, usually related to genetic, allergy, immunity and other factors. Patients may have symmetrical erythema, papules, papules on the skin of the arms, accompanied by itching, scratching can lead to skin erosion, oozing and so on. 3. Contact dermatitis: when the skin is in contact with allergic substances caused by allergic reactions, common allergic substances include soap, moisturizer, etc., arm area contact can appear erythema, papules, papules, with itching and other symptoms. Small blisters on the arm skin with itching symptoms may also be caused by other diseases, it is recommended that patients go to the hospital in a timely manner, a clear diagnosis under the guidance of the doctor for targeted treatment.