Bullous Pemphigoid (BP)

Figure 3.26 A: Bullous pemphigoid (Courtesy of Dr. Paul Getz) B: Bullous pemphigoid (Courtesy of Dr. Iris K. Aronson) C: Bullous pemphigoid (Courtesy of Dr. Iris K. Aronson)

• Most common autoimmune bullous disorder with chronic nature; typically in patients over 60
• Autoantigen:
  • BPAG2 (collagen XVII): 180 kDa (NC16A domain), transmembrane hemidesmosomal protein
  • BPAG1: 230 kDa, cytoplasmic plaque protein
• Clinical: often presents with initial urticarial lesions which evolve into large, tense bullae over medial thighs, groin, abdomen, and legs; ± pruritus initially with subsequent tenderness; no constitutional symptoms unless extensive disease; 10–35% with oral involvement
• Drug-induced: furosemide, NSAIDs, phenactin, PCN- derivates, gold, potassium iodide, captopril, enalapril, D-penicillamine, sulfasalazine



Drug-induced: PF ChaNGSPenicillamine PCN-derivates Phototherapy Furosemide Captopril NSAID Gold Sulfasalazine



• Histology: subepidermal bulla with ↑↑ eosinophils and lymphocytes in papillary dermis, ± neutrophils
• DIF: linear C3 and IgG (latter weaker) at BMZ
• IIF: + in 60–80%; IIF on salt-split skin (SSS) shows binding to epidermal side of split (roof of blister)
• Treatment: oral corticosteroid, steroid-sparing agent (azathioprine, mycophenolate mofetil, etc.), TCN + nicotinamide, dapsone; good prognosis