Bullous Pemphigoid: Causes, Symptoms and Treatment
Bullous pemphigoid is a very rare autoimmune skin disorder. Its incidence is estimated at 2.8 patients per 10,000 people in the United States, almost always in their 60s. The condition causes a variety of symptoms on the skin, most notably blistering.
It’s generally considered benign, but an annual mortality rate of 23-28% of sufferers is reported. This may be related to the patients’ age and their fragile overall health, rather than by the disease itself. Interested in learning more about it?
What is bullous pemphigoid?
Bullous pemphigoid (BP) is the result of a dysfunction in the patient’s immune system. Specifically, patients present autoantibodies at the dermoepidermal junction, the structure that separates the dermis from the epidermis.
Biopsies of the lesions show type G immunoglobulin and components of Complement 3 (C3) in virtually all cases. Some accessory immunoglobulins, such as IgM, IgA, IgE or IgD, can also be observed in the blisters. In any case, as mentioned, IgG is the most prevalent, in almost 90% of cases.
The presence of these antibodies in the lesions is evidence that the immune system is mistakenly attacking the patient’s tissues. In this case, the antibodies work against the fibers connecting the dermis and epidermis. This results in localized inflammation and the lesions described above.
Thus, the pathogenesis of AP can be grouped into two distinct categories; an immunological response and one of an inflammatory nature. Both derive from the action of the cells that protect us against viral and bacterial infections.
The antibodies bind to BP180 and BP230 antigens, essential proteins in cell binding.
Causes of bullous pemphigoid
According to the MSD Manual, the cause of bullous pemphigoid is still unknown. However, here are some factors that may contribute to its occurrence.
1. Taking certain medications
Drugs such as furosemide, spironolactone, penicillin, antipsychotics and others can contribute to the appearance of bullous pemphigoid. According to a publication in DermNet NZ, the most common drugs that trigger it are PD-1 checkpoint inhibitors, which are essential in immunotherapeutic treatments for melanoma.
2. Physical factors
Physical trauma to the skin, radiation therapy for the treatment of cancerous tumors and phototherapy with ultraviolet light may also contribute to the development of bullous pemphigoid.
3. Predisposing conditions
Below is a list of diseases and health conditions that are related to bullous pemphigoid. Among them are the following:
- This pathology occurs in both sexes equally. It’s not linked to hormonal issues specific to men or women, as is the case with other disorders.
- A genetic predisposition is associated with the development of the disease.
- It’s more prevalent in elderly patients with neurological problems, such as people who’ve had a stroke or people with dementia.
- People with malignant neoplastic processes, i.e. some types of cancer, are more prone.
It’s important to note that this condition arises due to errors in the autoimmune system, so any factor that may “confuse” it may contribute to its development. As such, multiple pathologies are associated with bullous pemphigoid, but none is considered to be a trigger in all cases.
Generally, sufferers are over 60 years old. This condition is very rare in younger adults and children, but isolated cases have been reported in all age groups.
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Symptoms of bullous pemphigoid
The Spanish Academy of Dermatology and Venereology (AEDV) has carefully detailed a clinical description of the disease. First of all, a series of eczema-like lesions typical of urticaria – which are very itchy – appear, on which large blisters form which do not burst easily.
Itching is almost always the first symptom to develop, as the blisters may not show until several years after the disorder. As the immune system creates antibodies that damage the dermoepidermal junction, the blisters become more obvious, painful and reddened.
Typically, these blisters appear in skin folds, especially in areas where repeated bending movements occur. Because of this, it’s uncommon for patients to show blistering lesions on the head and neck.
The Cleveland Clinic emphasizes that the first step in diagnosing bullous pemphigoid is a physical examination. The medical professional will also ask the patient for a medical history, looking for certain relevant information, such as the following:
- When the symptoms first appeared
- The associated sensations
- Family history
After establishing a differential diagnosis, doctors will ask for blood tests and take a biopsy from the affected area. These may show the presence of antibodies that attack the body’s tissues, confirming the immune disorder.
Treatment of bullous pemphigoid
According to information from the U.S. National Library of Medicine, corticosteroids are usually the first line of treatment for BP. They relieve skin inflammation, burning sensations and pain. In addition, they contribute to the suppression of misdirected immune responses in the body.
The most commonly used corticosteroid is prednisone, a synthetic drug that’s usually taken orally, but can also be injected intramuscularly. It’s often used to treat flu, asthma, fever and coughs, as it acts to suppress almost the entire immune system of the person.
Prednisone treatment is often systemic and is prescribed as an oral tablet – 60 to 80 milligrams – once a day. In more localized variants of the disease, clobetasol, a topical cream that reduces symptoms and avoids the use of many general drugs, can be used.
If corticosteroids don’t work, other more potent immunosuppressive drugs will be used.
The death rate in patients with untreated bullous pemphigoid is 18% per year. However, this is related to the age and health of the presenting patients. In most cases, pemphigoid disappears after a few months or years, even without treatment.
Most affected individuals who respond to corticosteroid treatment show remission of symptoms within 2 to 10 months. Even so, patients may require oral medication for several years. This will prevent the immune system from getting out of control again and causing the epidermal damage discussed above.
What should you remember?
This is a clinical pathology that’s difficult to understand and deal with because, as with many other autoimmune disorders, finding a specific cause is a complex task. Certain predisposing factors exist, but none of them seems to be a clear and universal trigger of bullous pemphigoid.
In addition to the difficulty in finding the cause, it’s important to note that treatment isn’t effective in all patients. This fact can greatly worsen the prognosis of the disease, especially considering that most of those affected are already of advanced age and have other health conditions.It might interest you...