Localised bullous pemphigoid overlying knee arthroplasty: a diagnostic challenge

Area of Science:

• Dermatology
• Immunodermatology
• Surgical Complications

Background:

• Bullous pemphigoid (BP) is an autoimmune blistering disease.
• Total knee arthroplasty (TKA) is a common orthopedic procedure.
• Post-surgical blistering can have various etiologies.

Observation:

• An elderly woman developed blistering post-TKA for osteoarthritis.
• Initial differential diagnoses included soft tissue swelling, bullous impetigo, and allergic contact dermatitis.
• Blistering progressively spread down the legs and to the hips over weeks to months.

Findings:

• Histopathology (H&E) and direct immunofluorescence confirmed bullous pemphigoid.
• A concomitant wound infection was identified and managed.
• The patient's bullous pemphigoid responded favorably to superpotent topical corticosteroids and local wound care.

Implications:

• This case highlights bullous pemphigoid as a rare but possible complication following total knee arthroplasty.
• Early diagnosis through biopsy and immunofluorescence is crucial for appropriate management.
• Multifaceted treatment addressing both the blistering disease and any concurrent infection is essential for patient recovery.