Pemphigus is a rare disease and autoimmune disorder that is characterized by group of skin disorders that cause blisters and sores on the mucous membranes of the nose, eyes, mouth, and genitals. It is not contagious. There are two main types of pemphigus: pemphigus vulgaris and pemphigus foliaceus. Pemphigus vulgaris is the most common type. Pemphigus can occur at any age, however, people who are middle aged or older are most often affected. It is estimated that about 1 in 20,000 to one in a million people develop some form of pemphigus each year.