QUINOLONE HYPERSENSITIVITY REACTION: A DIFFERENCE BETWEEN GENERATIONS; PLEASE MIND THE GAP

Abstract

Introduction Hypersensitivity reactions to fluoroquinolones continue to be rare with documented cases of low cross-reactivity between different classes. The reference standard is open oral challenge as there is no validated skin test. This case presents a unique presentation of levofloxacin allergy with tolerance to ciprofloxacin. Case Description A 53-year old gentleman, with a history of liver transplantation due to primary sclerosing cholangitis, presented to outpatient Allergy clinic for history of urticaria of the posterior neck and chest, diarrhea, and hypotension after receiving one dose of levofloxacin for acute cholangitis one month prior. The patient had recurrent episodes of cholangitis requiring quinolones as the drug of choice for treatment with no equally efficacious alternatives available. The patient underwent skin testing to published non-irritant concentrations of levofloxacin, ciprofloxacin, and moxifloxacin that were all negative. Next, he underwent an open oral challenge test to levofloxacin, in which he tolerated the 50 mg dose but did not tolerate the full therapeutic dose of 500 mg. He developed urticaria on his posterior neck (Figure 1) within 10 minutes which resolved after treatment with diphenhydramine. One week later the patient tolerated an open oral challenge to ciprofloxacin without adverse reactions. Conclusion This case demonstrates the importance of completing allergy evaluations with an open oral challenge after negative skin testing in patients with fluoroquinolone hypersensitivity. Cross-reactivity is less common between 1st (ciprofloxacin) and 3rd (levofloxacin) generation quinolones. Allergy evaluation can aid with antibiotic stewardship in determining which antibiotics can be safely administered.