54: Bullous Pemphigoid Flashcards
What is bullous pemphigoid and how does it typically present in patients?
Bullous pemphigoid is the most common autoimmune blistering disorder in adults, typically presenting as pruritic, tense blisters often on a background of urticarial plaques. It occurs most frequently in older adults and is characterized by large, tense blisters arising on normal skin or on an erythematous or urticarial base.
What are the common clinical features and findings associated with bullous pemphigoid?
The classic form of bullous pemphigoid is characterized by large, tense blisters on normal or erythematous skin, most commonly found on flexural surfaces, lower abdomen, and thighs. It features negative Nikolsky and Asboe-Hansen signs, intense pruritus, and nonbullous lesions may be the first manifestation in almost half of patients.
What is the epidemiology of bullous pemphigoid regarding age and incidence?
Bullous pemphigoid typically occurs in patients older than 60 years of age, with a peak incidence in the 70s. There is no known ethnic, racial, or sexual predilection associated with the condition.
What are the complications associated with bullous pemphigoid?
Complications may include skin infections developing within denuded bullae, dehydration, electrolyte imbalance, possible death from sepsis, and complications caused by bacterial and viral infections.
What diagnostic methods are used to confirm bullous pemphigoid?
Diagnosis of bullous pemphigoid is confirmed by routine histology, direct immunofluorescence (IF), indirect IF, or enzyme-linked immunosorbent assay (ELISA).
What are the typical clinical features of bullous pemphigoid in older adults?
Bullous pemphigoid typically presents as large, tense blisters on normal skin or an erythematous/urticarial base, most commonly found on flexural surfaces, lower abdomen, and thighs. Pruritus is usually intense but can be minimal.
Discuss the immunological mechanisms involved in the pathogenesis of bullous pemphigoid.
Bullous pemphigoid is characterized by autoantibodies directed against hemidesmosomal proteins BP180 and BP230, triggering an inflammatory cascade leading to blister formation.
What are the potential complications associated with bullous pemphigoid?
Complications include skin infections, dehydration, electrolyte imbalance, and possibly death from sepsis, necessitating careful monitoring and management strategies.
What is the most likely diagnosis for a 70-year-old patient with large, tense blisters?
The most likely diagnosis is bullous pemphigoid. Diagnostic tests include routine histology, direct immunofluorescence (IF), indirect IF, or enzyme-linked immunosorbent assay (ELISA).
What could be the precipitating factor for localized tense bullae in a patient with a history of radiation therapy?
The localized bullous pemphigoid could be precipitated by changes induced by radiation therapy.
What is lichen planus pemphigoides?
This condition typically affects middle-aged patients and is more localized to the extremities with a less severe clinical course.
What is the role of the Bullous Pemphigoid Disease Area Index (BPDAI) in clinical practice?
The BPDAI is a validated tool used to objectively measure clinical disease activity in patients with bullous pemphigoid.
What percentage of patients with bullous pemphigoid exhibit elevated serum IgE levels and peripheral blood eosinophilia?
Approximately 75% of patients have elevated serum IgE levels, and more than half have peripheral blood eosinophilia.
What triggers the inflammatory cascade that results in blister formation in bullous pemphigoid?
Autoantibody binding to hemidesmosomal antigens triggers an inflammatory cascade that ultimately results in blister formation.
What are the two distinct antigens recognized by bullous pemphigoid autoantibodies?
Bullous pemphigoid autoantibodies recognize two distinct antigens with molecular weights of 230 kDa (BP230) and 180 kDa (BP180).
What is the predominant cell type found in the inflammatory infiltrate of bullous pemphigoid?
The predominant cell type found in the inflammatory infiltrate of bullous pemphigoid is eosinophils.
What role do IgG antibodies play in the pathogenesis of bullous pemphigoid?
IgG antibodies generate dermal–epidermal separation in the presence of complement and leukocytes, contributing to the pathogenesis of bullous pemphigoid.
What are some risk factors associated with bullous pemphigoid?
Risk factors include HLA-DQB1*0301 associated with classic bullous pemphigoid, certain HLA alleles in Japanese patients, and neurological diseases increasing the risk of developing BP.
What are the key immunopathological mechanisms involved in the formation of blisters in bullous pemphigoid?
The formation of blisters is primarily due to autoantibody binding, inflammatory cell infiltration, proteolytic activity, and recruitment of inflammatory cells.
How do BP180 and BP230 contribute to the pathophysiology of bullous pemphigoid?
BP180 is involved in anchoring the epidermis to the dermis, while BP230 stabilizes the cytoskeleton of basal cells. Autoantibodies against both trigger inflammatory responses leading to blister formation.
What role do risk factors such as HLA alleles play in the development of bullous pemphigoid?
Risk factors include HLA-DQB1*0301 associated with classic bullous pemphigoid, and specific HLA alleles linked to increased risk in Japanese patients.
What are the clinical implications of the presence of autoantibodies against BP180 and BP230?
Detection of these autoantibodies is crucial for diagnosis, correlating with disease severity and treatment response.
What are the potential triggers for bullous pemphigoid?
Potential triggers include ultraviolet light, radiation therapy, and certain medications.
What are the two main antigens targeted by autoantibodies in bullous pemphigoid?
The two main antigens are BP230 (BPAG1) and BP180 (BPAG2), located in the hemidesmosome and the basement membrane, respectively.
