Importance Predominantly neutrophilic infiltrates are seen in a subset of patients with urticaria. The lesions tend to be less itchy and poorly responsive to standard therapy, including antihistamines. We describe 2 patients having neutrophilic urticaria with systemic inflammation (NUSI) without known connective tissue disorder or malignancy. We propose the term NUSI to help classify a previously undefined multisystemic inflammatory entity likely mediated by interleukin 1 (IL-1).
Observations Patient 1, a 47-year-old woman, was seen with urticaria and associated night sweats, fevers, and polyarticular arthritis. Acute-phase reactants were elevated with worsening of symptoms. Initial treatment with a combination of topical and systemic corticosteroids, antihistamines, and immunosuppressants was unsuccessful. A 100% clinical resolution was achieved with anakinra, an IL-1 receptor antagonist. Patient 2, a 24-year-old woman, was seen with urticaria and associated joint pain and swelling. Initial treatment included a combination of antihistamines, colchicine, and dapsone. Only colchicine provided moderate benefit but was stopped because of significant gastrointestinal tract discomfort. Anakinra was initiated; the patient achieved 100% control while receiving daily therapy.
Conclusions and Relevance The diagnosis of NUSI is important to consider in patients who are seen with antihistamine-resistant urticaria in combination with systemic inflammatory symptoms. Interleukin 1 blockade is a viable option for therapy.