Pemphigus is the term used to describe a group of autoimmune diseases that cause the skin and mucous membranes to become blistered. The conditions may therefore affect areas of the body such as the mouth, eyes, nose, throat, or genitals. In some cases, these diseases may be fatal if they are left untreated.

Pemphigus affects individuals from various races and ethnicities, but some studies have shown that European Jewish individuals and individuals of Mediterranean descent are more prone to these diseases. One form of the disease is more common among people who live in the Brazilian rain forests. Pemphigus affects men and women equally and several studies have demonstrated that the diseases are associated with a genetic predisposition to developing them. The onset of disease symptoms usually begins during adulthood, although symptoms have been found to occur in children.

There are several forms of pemphigus, depending on which layer of the skin is blistered and where the blistering is located. The blisters always appear on or near the skin surface. The different forms of pemphigus are described in more detail below.

Pemphigus Vulgaris

This is the most common form of pemphigus. The condition usually affects the mouth first and it can be painful. The blisters start to appear on skin and mucous membranes that were previously healthy looking. They form inside the deep layer of the epidermis and the skin becomes so delicate that simply rubbing it with a finger can cause it to fall off. Usually, the blisters heal without causing any scarring, but some areas of the skin that have become pigmented may stay so for several months.

Pemphigus Foliaceus

Pemphigus foliaceus is another common form of pemphigus. In this type, blisters or crusty sores initially develop on the scalp and face, with other areas of the body such as the chest becoming affected later. The lesions are often itchy, but are not usually as painful as those that develop in pemphigus vulgaris. Areas of the skin may also become moist, loose, and scaly.

Pemphigus Vegetans

This form of the disease causes thick sores to arise under the arms and in the groin area.

IgA Pemphigus

Here, immunoglobulin A (IgA), an antibody  different from the antibodies involved in other forms of the condition binds to the epidermis cell surface. The resulting blisters are similar to those that develop in pemphigus foliaceus, although sometimes pus-containing bumps also arise. IgA pemphigus is the least harmful type of pemphigus.

Paraneoplastic Pemphigus

This is a rare condition that is not actually pemphigus, but shares some of the disease characteristics. It develops in people with certain cancers and leads to ulcers forming in the mouth and on the lips. The skin also becomes blistered and the eyelids may become cut and scarred. The antibody that binds to the surface of epidermis cells also targets the membranes of the airways and hence patients with this condition can develop fatal lung problems.