Description

• Bullous pemphigoid (BP) is an antibody-mediated blistering skin disease.
• Intraepidermal blistering with widespread eruption of tense, symmetric, pruritic blisters on apparently normal skin or mucous membranes
• Common sites are the oral cavity (10–20% of cases) and the skin of the inner thighs, flexor surface of the forearm, groin, axilla, and lower abdomen.

Epidemiology

• ∼61% of affected persons are females. Most common in persons age >60 years.
• Laryngeal mucous membrane pemphigoid disease has similar frequency in men and women.
• Childhood BP is very rare, and it most commonly involves acral regions. It follows a benign, short course, <1 year in most cases.

Incidence
In the UK, occurrence is 4.28/100,000 person-years.

Prevalence
4.8 new cases/100 elder-years

Risk Factors

• Association with autoimmune disorders and inflammatory dermatoses, such as lichen planus and psoriasis. Association with neurologic disorders, such as multiple sclerosis, stroke, Parkinson disease, and psychiatric disorders
• Drug-induced BP is rare: Furosemide, NSAIDs, captopril, aldosterone antagonists, penicillin, sulfasalazine, salicylazosulfapyridine, phenacetin, nalidixic acid, topical fluorouracil
• Less frequent: Trauma, burns, surgical scars, ultraviolet (UV) radiation, and x-ray therapy
• Paraneoplasic (1)

Genetics
Expression of the major histocompatibility complex (MHC) class II allele DQB1*0301 appears to be a marker for enhanced susceptibility.

Pathophysiology

• Autoantibodies are formed against the protein components BP180 and BP230 of the hemidesmosomes in the dermoepidermal junction.
• IgG autoantibodies bind to these antigenic proteins, activating complement, which attracts inflammatory cells; inflammatory cells release proteases, which degrade the hemidesmosomes, leading to disruption of the dermoepidermal junction.
• BP180 appears to be the main pathogenic antigen causing subepidermal blister formation.
• A link between autoimmunity to BP230 and neurologic disease has been suggested.
• NC16A antibodies present in 82–94% of patients.
• IgE autoantibodies against BP180 seem to be associated with the early urticarial phase of the disease and are detected in 86% of untreated patients with BP. The presence of IgE autoantibodies correlates with a more severe form of BP that requires longer and more intensive treatments for remission and higher doses of corticosteroids.

Etiology

Autoimmune

Commonly Associated Conditions

Multiple sclerosis; hypereosinophilic syndrome; ulcerative colitis; neurological disease