Bullous pemphigoid, a variant of pemphigoid that mainly affects adults over 60, is an autoimmune skin condition that can cause blisters (called bullae) to develop between the dermal and epidermal layers of the skin. It is categorized as a type II hypersensitivity reaction, which results in the loss of keratinocytes’ ability to adhere to the basement membrane and the production of anti-hemidesmosome antibodies.
Symptoms and signs
Clinically, the first lesions may present as a red, raised rash that resembles hives, but they may also take the form of dermatitic, targetoid, lichenoid, nodular, or even be absent of a rash (essential pruritus). The inner thighs and upper arms are the most typical places for tense bullae to emerge, but the trunk and extremities are frequently also affected. The skin surface can be affected everywhere. In a small percentage of cases, oral lesions are present. The illness may be acute, but it also has a range in duration, with phases of exacerbation and remission, from months to years. Similar symptoms may also be present in other skin conditions. However, because to the deeper antigenic targets in epidermolysis bullosa acquisita, milia are more frequent. A more ring-like pattern with a central depression or bullae that have collapsed in the centre may be a sign of linear IgA illness. In contrast to pemphigus vulgaris, where it is positive, Nikolsky’s sign is negative.
Causes
There are typically no definite triggering factors found in cases of bullous pemphigoid. It has been suggested that radiation therapy and exposure to ultraviolet light are potential triggering factors.A number of medications, including furosemide, nonsteroidal anti-inflammatory medicines, DPP-4 inhibitors, captopril, penicillamine, and antibiotics, have also been linked to the onset of pemphigoid.
Pathophysiology
The development of IgG[6] autoantibodies against dystonin, also known as bullous pemphigoid antigen 1, and/or type XVII collagen, also known as bullous pemphigoid antigen 2, which is a part of hemidesmosomes, triggers an immunological response that results in the creation of the bullae. Neuropathy and a distinct type of dystonin are related. Following antibody targeting, a series of immunomodulators cause a varied influx of immune cells to the afflicted location, including neutrophils, lymphocytes, and eosinophils. The dermoepidermal connection gradually separates as a result of unknown causes, which stretches bullae.
Diagnosis
A bullous pemphigoid in microscopy- blistering beneath the epidermis and an influx of inflammatory cells, such as neutrophils and eosinophils, into the dermis and blister cavity.
The two out of three rule states that in order to diagnose an illness, at least two of the three criteria must be met. These criteria are: (1) pruritus and/or predominant cutaneous blisters; linear IgG and/or C3c deposits (in an n-serrated pattern) by direct immunofluorescence microscopy (DIF); and positive epidermal side staining by indirect immunofluorescence microscopy on human salt-split skin (IIF SSS)
Routine ELISA or H&E staining tests do not improve the initial diagnosis.
Treatment
Topical steroids like clobetasol and halobetasol are used as treatments and have been shown in certain studies to be somewhat safer and equally effective as systemic, or pill, therapy.
Systemic prednisone and potent steroid-free immunosuppressants such methotrexate, azathioprine, or mycophenolate mofetil may be necessary in difficult-to-treat or widespread instances, though.
Some of these drugs may cause serious side effects such kidney and liver damage, an increased risk of infection, and bone marrow suppression. Tetracycline and erythromycin are two antibiotics that may help treat the condition, especially in patients who are unable to take corticosteroids. It has been discovered that the anti-CD20 monoclonal antibody rituximab can treat some pemphigoid cases that are ordinarily resistant to treatment.
Even with typically effective drugs like rituximab, IgA-mediated pemphigoid can frequently be challenging to cure.
Bullous pemphigoid may self-resolve in a few months to many years even without therapy, according to the prognosis.
A worse prognosis is linked to poor general health in old life.
This video illustrates all the key facts of Bullous Pemphigoid.
I am Dr Shashikant, a pathologist,professor and medical writer by profession. Please contact-ruc.isha@gmail.com for medical writing, Pathology online tutoring for usmle,neetpg,plab,fmge,mbbs,md
