Successful Diflunisal Desensitization in a Transthyretin Amyloidosis Patient with NSAID Allergy: A Case Report

Introduction: Amyloid diseases have been known to be hereditary, including transthyretin (TTR) amyloidosis where subunit protein mutations may occur in genes for TTR leading to the deposition of fibrils (low molecular weight subunits (5 to 25 kD) of proteins) in extracellular tissues. By reducing the formation of TTR amyloid, diflunisal, a nonsteroidal anti-inflammatory drug (NSAID), has shown to preserve the quality of life and significantly reduce disease progression. We report a case of successful diflunisal desensitization in a patient with transthyretin amyloidosis. Case description: A 61 year-old gentleman with history of ibuprofen allergy was diagnosed with transthyretin amyloidosis complicated with peripheral neuropathy, cardiac and liver amyloid. He developed bilateral eye swelling from ibuprofen oral provocation test. With a similar structural backbone of carboxylic acid, he could develop pseudoallergy to diflunisal, with unknown likelihood of developing an allergy reaction. The patient underwent a 14 steps diflunisal desensitization procedure and was able to tolerate diflunisal following the procedure. Conclusion: Diflunisal desensitization can be considered in patients with history of NSAIDs allergy if there is no alternative treatments available. To the best of our knowledge, this is the first article describing a patient with angioedema to ibuprofen who could tolerate oral diflunisal after desensitization.