Around last 2 years, my father is having blisters forming on scalp, mouth. It is on and off. Has been receiving different medicines, it goes away and comes back. Offlet skin infection has also developed in lower part which again comes and goes. Consulted dermatologist who suggested Desmoglein 1&3 test which came back negative with primary titre 1:10. All other blood tests are normal. He is diabetic for over 7 years and on medication. The issue of skin is very difficult to get away. Please suggest and guide