ABSTRACT
The Center for Disease Control guidelines recommend desensitization to metronidazole in patients with trichomoniasis and hypersensitivity to metronidazole. There is only one published oral metronidazole desensitization protocol. The purpose of this study was to design a new, more gradual oral desensitization protocol to decrease systemic reactions that may occur when using the previously published protocol. We present two patients with presumed IgE-mediated allergy to metronidazole who underwent oral desensitization using our modified protocol. Case 1 was a 65-year-old woman with trichomoniasis who presented for metronidazole desensitization with a history of intraoperative anaphylaxis and positive skin tests to metronidazole. The patient tolerated six doses of the modified desensitization but developed systemic symptoms of nasal congestion and diffuse pruritus after the 25- and 100-mg doses. Both reactions were treated with intravenous (i.v.) antihistamines. Because of gastrointestinal irritation, the desensitization was completed at a dose of 250 mg orally every 6 hours. Case 2 was a 42-year-old woman with trichomoniasis and a history of hives immediately after administration of i.v. metronidazole who presented for desensitization. The patient had negative skin-prick and intradermal testing to metronidazole. She developed lip tingling and pruritus on her arms 15 minutes after the 10-mg dose. Fexofenadine at 180 mg was given orally and symptoms resolved. She tolerated the rest of the protocol without reaction and received a total dose of 2 g of metronidazole. Our oral metronidazole desensitization for presumed IgE-mediated reactions offers a second option for physicians wishing to use a more gradual escalation in dose.
ABSTRACT
BACKGROUND: Laboratory tests are routinely ordered to identify or rule out a cause in patients with chronic urticaria/angioedema (CUA). The results of these tests are usually within normal limits or unremarkable. OBJECTIVE: To investigate the proportion of abnormal test results in patients with CUA leading to a change in management and in outcomes of care. METHODS: Retrospective analysis of a random sample of adult patients with CUA from 2001-2009. RESULTS: Cases totaled 356: 166 with urticaria and angioedema (AE), 187 with urticaria, and 3 with only AE. Patients were predominately women (69.1%) and white (75.6%), with a mean age of 48 ± 15 years. Abnormalities were commonly seen in complete blood counts (34%) and in complete metabolic panels (9.4%). Among the 1,872 tests that were ordered, results of 319 (17%) were abnormal. Of 356 patients, 30 underwent further testing because of abnormalities in laboratory work. This represented 30 of 1,872 tests (1.60%). Only 1 patient benefited from a subsequent change in management. CONCLUSIONS: Laboratory testing in CUA patients referred for an Allergy and Immunology evaluation rarely lead to changes in management resulting in improved outcomes of care.
