HOUSTON (FRONTLINE MEDICAL NEWS)The higher prevalence of chronic urticaria in patients with self-reported penicillin allergy suggests that these patients may be confusing one condition with the other, according to a late-breaking study presented at the annual meeting of the American Academy of Allergy, Asthma, and Immunology.

A retrospective chart review of 1,419 patients with self-reported penicillin allergy revealed that 175 patients (12.3%) had a diagnosis of chronic urticaria, a significantly higher percentage than the typical prevalence range of 0.5%-5% that has been reported in the general population.

“Patients are potentially mistakenly attributing symptoms of chronic urticaria to a penicillin allergy,” explained study author Dr. Susanna G. Silverman of the University of Pennsylvania, Philadelphia.

The study included patients at the University of Pennsylvania’s allergy and immunology clinic who self-reported penicillin allergy from June 2007 to August 2014. Patients were identified as having penicillin allergy if penicillin, amoxicillin, amoxicillin-clavulanate, or piperacillin-tazobactam were present on the allergy list of their medical records.

Dr. Silverman then identified all patients from that group who also received a diagnosis of urticaria – a total of 343 patients – then narrowed the list to those who were diagnosed with chronic urticaria or the presence of urticaria for at least 6 weeks.

Of the 175 patients who had chronic urticaria, all were between the ages of 20 years and 92 years; 84% were female, and 53% were white.

“We think it’s important for physicians to think about this and to ask patients about symptoms of chronic urticaria when they report penicillin allergy,” Dr. Silverman noted, “to better determine what is truly penicillin allergy versus simply chronic urticaria symptoms.”

Dr. Silverman did not report any financial disclosures.