Pemphigus is an autoimmune disorder. If you have it, your immune system attacks healthy cells in your skin and mouth, causing blisters and sores. No one knows the cause. Pemphigus does not spread from person to person. It does not appear to be inherited. But some people's genes put them more at risk for pemphigus.
Pemphigoid is also an autoimmune skin disease. It leads to deep blisters that do not break easily. Pemphigoid is most common in older adults and may be fatal for older, sick patients.
Doctors diagnose pemphigus with a physical exam, a biopsy, and blood tests. The treatment of pemphigus and pemphigoid is the same: one or more medicines to control symptoms. These may include
NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases