Common causes of itchy blisters on the back of the hands include eczema, contact dermatitis and ringworm. 1. Eczema: can be caused by a variety of reasons, such as the presence of chronic foci of infection in the body, eating allergic foods, chemical fiber clothing stimulation. In the acute stage, there are usually blisters, papules, vesicles and oozing at the lesions, which can appear on the back of the hands, but also on any part of the body. 2. Contact dermatitis: an inflammatory reaction that occurs when the skin on the back of the hands is exposed to certain sensitizing or irritating substances. It can also cause itchy blisters on the back of the hands. 3. Ringworm: mostly caused by fungal infections, mainly involving the thumb, palm of the hand, when the lesion is serious, can spread to the back of the hand, manifested as dry, flaky, blisters and other symptoms, can be accompanied by itching. It can be spread through direct contact and indirect contact. As you can see, when small blisters appear on the back of the hand is very itchy, it is recommended to go to the regular hospital in time to clarify the diagnosis, according to the cause of the symptomatic treatment.