Itchy blisters on the back of the feet may be caused by eczema, contact dermatitis, tinea pedis and other diseases. 1. Eczema: Eczema is a chronic inflammatory itchy skin disease, the cause of which is related to genetics, immune abnormalities, endocrine and metabolic diseases, often appearing in the head, face, hands and feet, etc., localized polymorphic rashes, initially in the erythema on the basis of the appearance of millet-sized papules, accompanied by intense itching. 2. Contact dermatitis: contact dermatitis is caused by skin contact with exogenous substances that irritate the skin or cause an allergic reaction. Patients will appear localized skin intensive pimples, blisters, accompanied by itching and other symptoms. 3. Tinea pedis: Tinea pedis is caused by dermatophyte infection, manifested as blisters, keratinization, desquamation, etc. Patients will be self-conscious of itching, often occurring in the foot. The back of the foot is very itchy blisters cause more reasons, it is recommended to consult a doctor to check, a clear diagnosis.