Epidermolysis Bullosa Acquisita

Epidermolysis bullosa acquisita (EBA) is a rare, chronic autoimmune subepidermal blistering disease caused by IgG autoantibodies against type VII collagen of the anchoring fibrils.

• Incidence is 0.2 to 0.5 per million per year; onset in adults (30 to 60) but can occur in children.
• Associations: inflammatory bowel disease (especially Crohn disease), SLE, rheumatoid arthritis, thyroiditis, amyloidosis, and multiple myeloma.
• HLA-DRB1*15:03 is linked to EBA in some populations.
• Scarring, milia, and mucosal strictures can cause lasting disability.

• Classical (mechanobullous): non-inflammatory skin fragility with tense blisters on trauma prone areas (hands, knees, elbows, feet), healing with scars, milia, nail dystrophy and loss, hair loss.
• Inflammatory variants: BP-like, mucous membrane pemphigoid like, Brunsting-Perry (head and neck scarring), and linear IgA-like.
• Oral, ocular, oesophageal, laryngeal, and anal involvement with stricture formation.

• Biopsy: subepidermal blister with variable inflammatory infiltrate.
• DIF: linear IgG (with C3) at the dermal epidermal junction; on salt split skin, deposits on the dermal side (floor of the blister), distinguishing from bullous pemphigoid (roof).
• ELISA (type VII collagen NC1) and indirect immunofluorescence on salt split skin.
• Immunoelectron microscopy for deposition beneath the lamina densa (when needed).
• Exclude hereditary epidermolysis bullosa (dystrophic), porphyria cutanea tarda, bullous pemphigoid, and bullous lupus.
• Screen for Crohn disease, SLE, and myeloma.

• Avoid trauma, protective dressings (silicone, non-adherent), infection control, and nutritional support.
• Colchicine 0.5 mg twice daily, up to 1 to 2 mg daily; helpful in mild or mechanobullous disease.
• Prednisolone 0.5 to 1 mg/kg/day for inflammatory subtype, tapered slowly; combine with steroid sparing agents.
• Immunosuppression: dapsone 50 to 150 mg (inflammatory subtype), ciclosporin 3 to 5 mg/kg/day, azathioprine 2 mg/kg, mycophenolate 1 to 1.5 g twice daily, methotrexate 10 to 25 mg weekly.
• Refractory: rituximab 375 mg/m2 weekly for 4 doses or 1000 mg x 2, IVIG 2 g/kg monthly, extracorporeal photopheresis, plasmapheresis.
• Oesophageal and anal stricture dilatation, ophthalmology and ENT care, and treatment of underlying associated disease.