Autoimmune Blistering Diseases

The skin is the largest organ of the body. In addition to serving as a protective barrier, the skin is involved in many additional functions of the body such as regulating internal body temperature. Five distinct layers make up the skin; each layer is filled with specialized cells. The two main structural layers of the skin are the epidermis – the outermost, protective layer of skin – and the dermis – an underlying layer that contains numerous specialized cells, tissues, and structures. Specialized proteins and structures are required for the dermis and epidermis to stick together. When the epidermis separates from the dermis a blister? (bulla) may form.

A blister? can be either tiny or large and consists of a fluid-filled bubble that forms underneath the surface of damaged or dead skin. Most blisters develop in response to irritation or injury of the skin. In autoimmune? blistering diseases, blisters form because the body creates antibodies that attack certain proteins required for the proper health and function of the skin. In many cases, blisters can rupture becoming open sores or wounds.

In some autoimmune? blistering diseases, blisters or lesions can also form on the mucous membranes, the thin, moist coverings of many of the body’s internal surfaces. Mucous membranes line the esophagus and anus, the inside of the mouth, the nasal passageways, the genitals, and the throat. Associated symptoms depend on the location of blister? formation, but can include gastrointestinal bleeding, difficulty swallowing, or difficulty breathing.

There are several different categories of autoimmune? blistering diseases including pemphigus, pemphigoid, IgA-mediated dermatoses, and epidermolysis bullosa acquista. Pemphigus, pemphigoid, and IgA-mediated dermatoses can be further broken down into additional subtypes.

Pemphigus

The term pemphigus is a general term for a group of related autoimmune? blistering diseases. The two main types of pemphigus are pemphigus vulgaris and pemphigus foliaceus. Each type has additional subtypes.

Pemphigus vulgaris is the most common form of pemphigus. It is characterized by blisters that rupture easily and cause painful erosions. In most cases, pemphigus Vulgaris first develops in the mouth, followed by blistering of the skin. Any area may potentially be affected. The blisters are usually not itchy.

Pemphigus foliaceus is characterized by multiple small, blisters that quickly break apart to form itchy (pruritic), scaly, crusted lesions that affect the uppermost layer of the skin. The scalp and face are usually affected first. Eventually, the chest, and upper back may become involved. The lesions are usually not painful. The mucous membranes are usually not affected.

Additional disorders are sometimes classified as subtypes of pemphigus including paraneoplastic pemphigus and pemphigus IgA. Some physicians consider these disorders similar, yet distinct, autoimmune? blistering diseases.

Paraneoplastic pemphigus is a rare disease that occurs in individuals who have cancer, especially blood (hematologic) cancers such as leukemia or lymphoma. Paraneoplastic pemphigus is characterized by painful lesions affecting the mucous membranes, especially those found in the mouth and the lips. The mucous membrane lining the inside of the eyelids (conjunctiva) is also frequently affected. In other cases, the lesions can affect the linings of the gastrointestinal or respiratory tracts and potentially cause life-threatening complications. In some cases, lesions affecting the skin may develop. These lesions may vary from case to case and may appear as small, reddened bumps (erythematous macules), non-firm (flaccid) blisters, scaly plaques, pustules, or erosions.

Pemphigus IgA, also known as intraepidermal neutrophilic IgA dermatosis, is characterized by the development of fluid-filled blisters on the skin. The mucous membranes are usually not affected. In most cases, the trunk and the upper arms or legs are affected. The scalp can be extensively affected in some people.

Pemphigoid

Pemphigoid is a general term for a group of related diseases characterized by blistering skin eruptions. The main forms of pemphigoid are bullous pemphigoid, mucous membrane pemphigoid, and pemphigoid gestationis.

Bullous pemphigoid is a chronic? skin disease usually affecting the elderly that is characterized by firm, large blisters that develop on normal-appearing or reddened skin on the trunk or skin folds, sometimes around cuts or scars. Within weeks, blisters often spread to the groin, armpit, abdomen, and the skin where muscle contracts or flexes (flexor muscles). In some cases, the lesions may become widespread covering a significant portion of the skin and blisters may form inside the mouth. In most cases, the mucous membranes are not affected and, when they are, they tend to heal quickly. The lesions of bullous pemphigoid are often associated with intense itching.

Mucous membrane pemphigoid (MMP) is a rare group of chronic? autoimmune? diseases characterized by blistering lesions that primarily affect the various mucous membranes of the body. The mucous membranes of the mouth and eyes are most often affected. The mucous membranes of the nose, throat, genitalia and anus may also be affected. The symptoms of MMP vary among affected individuals depending upon the specific site(s) involved and the progression of the disease. Blistering lesions eventually heal, sometimes with scarring. Progressive scarring may potentially lead to serious complications affecting the eyes and throat. In some cases, blistering lesions also form on the skin, especially in the head and neck area. Mucous membrane pemphigoid has been known by many different names within the medical literature including benign? mucous membrane pemphigoid, cicatricial (scarring) pemphigoid and ocular cicatricial pemphigoid.

Pemphigoid gestationis occurs in women during pregnancy or shortly after birth (postpartum period). Affected individuals develop reddish bumps or hives usually around the navel (umbilicus) and the arms and legs. The rash? may spread to affect other areas of the body and may be extremely itchy. Eventually, the skin lesions progress to form blisters. Pemphigoid gestationis usually resolves within three months without treatment (spontaneously).

IgA Mediated Bullous Dermatoses

IgA-mediated bullous dermatoses are disorders characterized by elevated levels within the body of a specialized protein known as immunoglobulin A (IgA). In these disorders, IgA has a particular tendency to accumulate in the skin. Dermatitis herpetiformis and linear IgA disease are IgA-mediated bullous dermatoses. When liner IgA disease affects children, it may be known as the chronic? bullous disease of childhood.

Dermatitis herpetiformis, also known as Duhring disease, is characterized by red clusters of extremely itchy (pruritic) blisters. The elbows, knees, scalp, and buttocks are most often affected. The mucous membranes are rarely involved. The symptoms of dermatitis herpetiformis tend to come and go. Most cases of dermatitis herpetiformis are associated with Celiac disease, a digestive disorder characterized by intolerance to dietary gluten, which is a protein found in wheat, rye, and barley.

Linear IgA disease is characterized by blistering eruptions on the skin. The elbows, knees, and buttocks are most often affected. New blisters may arise in areas where older blisters are – a finding that creates a small group of blisters that may be described as a “cluster of jewels”. In some cases, itching (pruritis) maybe develop and may occur before the development of skin lesions. In approximately 50 percent of cases, the mucous membranes are affected as well, especially the mucous membranes of the mouth and eyes. The eye involved can cause blurred vision, irritation, light sensitivity, and corneal scarring.

Epidermolysis Bullosa Acquista

Epidermolysis bullosa acquista is a rare autoimmune? disorder of the skin that typically affects middle-aged and elderly people. The skin of affected individuals is extremely fragile. Trauma to the skin can cause blisters to form. The elbows, knees, pelvis, buttocks, and/or scalp are most often affected. Increased levels of a specialized protein known as immunoglobulin G are usually found around the blisters. After the blisters heal, scars and small white bumps or cysts (milia) may remain. The mucous membranes are rarely involved. A subset of patients with epidermolysis bullosa acquista has a widespread, inflammatory form of the disorder that develops rapidly and often involves the mucous membranes.