Self-reported penicillin allergy could be chronic hives

PHILADELPHIA, Feb. 3 (UPI) -- A new study published in the journal Annals of Allergy, Asthma and Immunology explores the large overlap of patients who experience chronic hives and have a self-reported penicillin allergy.

Researchers with the American College of Allergy, Asthma and Immunology suspect the sizable overlap is more than just a coincidence.

"We wanted to know if there was a correlation between self-reported penicillin allergy and chronic urticaria," lead study author Dr. Susanna Silverman, an allergist and ACAAI member, said in a news release. "We found higher than expected incidence compared to the general population, and we wondered if some patients who believed they had penicillin allergy might actually have chronic urticaria."

Chronic hives, or chronic urticaria, is a condition whereby hives are present on a patient's body continuously or on and off for longer than 45 days.

Researchers surveyed 11,143 patients receiving treatment at the University of Pennsylvania Health System Allergy-Immunology Clinic. They identified 220 patients with a self-reported penicillin allergy and chronic urticaria.

Their analysis showed that those with a self-reported penicillin allergy were three times more likely than other patients to experience chronic urticaria. And patients with chronic urticaria were three times more likely to self-report a penicillin allergy.

Patients with penicillin allergies are usually given alternative antibiotics. But researchers say it's possible many patients are misinterpreting their chronic hives as a reaction to penicillin.

"It's important for anyone who thinks they have a penicillin allergy to be tested by an allergist," said study co-author Dr. Andrea Apter, also an allergist and ACAAI member. "If testing finds that someone with chronic urticaria and self-reported penicillin allergy isn't allergic to penicillin, it may be that their hives are simply due to chronic urticaria, or they may be more prone to rashes and hives throughout their lives, possibly due to increased skin sensitivity."