Safety and outcomes of "at-home self-provocation tests" in patients with mild nonsteroidal anti-inflammatory drug-induced urticaria/angioedema.

Background: Nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity is common; however, many patients do not receive an accurate diagnosis and are using unnecessary alternative drugs or have medication restrictions.

Objective: To establish a protocol for provocation tests that can be performed safely and effectively at home to give patients an accurate diagnosis, whereas also delabeling NSAID hypersensitivity.

Methods: We retrospectively analyzed the medical records of 147 patients with NSAID hypersensitivity. All patients had NSAID-induced urticaria/angioedema with less than 10% body surface area skin involvement. One specialist developed the protocol through history taking and chart review. If NSAID hypersensitivity was confirmed, an oral provocation test was performed to confirm the safe alternative medications (group A). If it was undetermined, an oral provocation test was performed to confirm the diagnosis and alternative medications (group B). All oral provocation tests were performed by patients in their homes according to the protocol.

Results: Approximately 26% of group A patients had urticaria or angioedema symptoms with alternative drugs, whereas the remaining 74% was safe. In group B, 34% of the patients were diagnosed with having NSAID hypersensitivity. However, 61% did not respond to the culprit drug; therefore, NSAID hypersensitivity had been misdiagnosed. During this at-home self-provocation test, no severe hypersensitivity reactions occurred.

Conclusion: Many patients originally suspected of having NSAID hypersensitivity were confirmed to have been misdiagnosed. We successfully conducted an effective and safe at-home self-provocation test.