Table of Contents
Definition of Pemphigus
Pemphigus is an autoimmune disorder in which large, painful bullae (blisters) form on the SKIN and mucous membranes. The bullae develop within the epidermis, the skin’s uppermost layer, giving them a very thin surface. They rupture and tear easily, exposing the skin to INFECTION and interfering with the skin’s ability to carry out its numerous functions.
The ruptured bullae form crusts while they heal, though typically heal without scarring. Some forms of pemphigus can cover large portions of the skin’s surface are potentially fatal. There are three main forms of pemphigus:
- pemphigus vulgaris, the most common form in which bullae develop in the MOUTH and under the eyelids as well as on the skin surfaces of the face, neck, chest, axillae (underarms), and groin
- pemphigus foliaceus, the mildest form in which bullae develop mostly on the skin of the scalp and face though sometimes involve the back and chest
- paraneoplastic pemphigus, which occurs only secondarily to CANCER and can involve the mucous membrane lining the ESOPHAGUS and airways (TRACHEA and bronchi)
Pemphigus occurs when antibodies the IMMUNE SYSTEM produces attack and destroy certain proteins on the surface of epidermal keratinocytes, the skin cells that make up the epidermis, causing them to separate from one another. The proteins are like glues that hold the keratinocytes together. Dermatologists do not know what causes pemphigus to develop as an autoimmune process, though occasionally it occurs as an ADVERSE REACTION to certain medications, notably penicillamine (taken to treat severe RHEUMATOID ARTHRITIS) and carbidopa/levodopa (taken to treat PARKINSON’S DISEASE).
Symptoms and Diagnostic Path
The primary symptom of pemphigus is the appearance of bullae that start as small blisters. In early outbreaks the blisters may rupture and heal without taking the characteristic bulla form. As outbreaks become more frequent and progressive, however, the blisters enlarge over several days to a week. In the early stages of the disorder’s manifestation, the pattern and appearance of bullae may be similar to other autoimmune symptoms, notably the sores that can appear with HIV/AIDS. Biopsy of the lesions can help to rule out other causes.
The location and extent of the bullae characterizes the form of pemphigus. Pemphigus vulgaris typically begins with blisters in the mouth, with outbreaks quickly following on other skin surfaces as well as the mucous membranes lining the NOSE and the URETHRA. The bullae of paraneoplastic pemphigus, which only occurs in conjunction with cancer, also originate in the mouth though quickly involve the esophagus as well as the skin. Pemphigus foliaceus bullae are smaller and remain confined primarily to the head (scalp and face), and do not involve the mouth or other mucous membranes.
Treatment Options and Outlook
Treatment targets relief of symptoms during outbreaks and mitigation of future outbreaks to the extent possible. Treatment varies with the form and severity of pemphigus, though typically includes oral or injected CORTICOSTEROID MEDICATIONS along with oral ANALGESIC MEDICATIONS for PAIN relief and ANTIBIOTIC MEDICATIONS to treat infection when necessary. Severe outbreaks may require IMMUNOSUPPRESSIVE MEDICATIONS to subdue the IMMUNE RESPONSE, or PLASMAPHERESIS, a therapy that cleanses the blood’s serum of antibodies. Cytotoxic drugs such as those used in CHEMOTHERAPY also improve symptoms in some people with severe outbreaks.
The most serious complication of pemphigus itself is loss of the skin’s ability to protect the body from bacterial invasion, resulting in widespread skin or systemic infection. However, pemphigus is a chronic condition that requires ongoing medication therapy. For many people who have pemphigus vulgaris, the more common and more severe form, the most significant complications arise from the long-term use of the medications necessary to control outbreaks.
These medications all have serious side effects and adverse consequences for other body structures and functions. Pemphigus that appears as an adverse DRUG reaction typically ends when the person stops taking the medication. Paraneoplastic pemphigus improves with treatment for the underlying cancer, though may cause life-threatening pulmonary complications when it affects the airways.
Risk Factors and Preventive Measures
Because doctors do not know the mechanisms that set pemphigus in motion, there are no identified risk factors. The condition tends to first manifest in people who are age 40 or older, though can occur at any age. Researchers suspect GENE mutations underlie pemphigus as they do other AUTOIMMUNE DISORDERS, though have not yet been able to identify them. Early diagnosis and aggressive treatment are key to mitigating symptoms and outbreaks, improving QUALITY OF LIFE as well as helping preserve other structures and functions. People who have milder forms of pemphigus may go extended periods without symptoms.