Pemphigus (/ˈpɛmfɪɡəs/ or /pɛmˈfaɪɡəs/) is a rare group of blistering autoimmune diseases that affect the skin and mucous membranes. In pemphigus, autoantibodies form against desmoglein. Desmoglein forms the "glue" that attaches adjacent epidermal cells via attachment points called desmosomes. When autoantibodies attack desmogleins, the cells become separated from each other and the epidermis becomes "unglued", a phenomenon called acantholysis. This causes blisters that slough off and turn into sores. In some cases, these blisters can cover a significant area of the skin.