Women at Greater Risk for Penicillin Allergy than Men

January 6, 2005
Internal Medicine World Report, January 2005,

Women at Greater Risk for Penicillin Allergy than Men

For the first time researchers have identified female gender as a risk factor for a penicillin allergy. Among patients with a history of penicillin allergy who were skin tested for penicillin, the majority of those who tested positive were women, data presented at the American College of Allergy, Asthma & Immunology meeting show.

Lead investigator Miguel Park, MD, of the Mayo Clinic, Rochester, Minn, presented the results of the study. “We found that women seem to have a 4-fold greater risk than men of having a positive penicillin skin test. The literature indicates that people who say they have a penicillin allergy will only have a positive skin test for penicillin 10% of the time. This study is the first to look at gender and analyze what percentage of women who report having a penicillin allergy will have a positive skin test,” Dr Park said.

This study included 19,429 patients who were seen in the preoperative evaluation clinic between June 2002 and June 2004. Of this cohort, 1921 patients were identified with a history of positive penicillin allergy, of which 1759 (mean age, 60 years) underwent skin testing for penicillin.

A total of 64 patients (3.6%) tested positive for penicillin allergy. The surprising finding was that of these, 53 (83%) were women and only 11 (17%) were men. Of those with a negative/equivocal penicillin skin test, 960 (57%) were women compared with 720 (43%) men. Even when adjusting for age and history of multidrug allergies, female gender was still associated with a positive penicillin test in a multivariate logistic regression analysis.

“Primary care physicians should be a little more careful with women patients. This was a retrospective study, and we need to do a prospective study, but physicians should be aware that female patients who have a history of penicillin allergy might have a true penicillin allergy more often than their male counterparts,” explained Dr Park. “The literature seems to suggest that women are more prone to having an adverse drug reaction than men, so this study is in line with the literature.”

Todd Mahr, MD, of the University of Wisconsin, La Crosse, noted that although this study had a large number of patients, it was conducted at just 1 institution, and that these findings need to be replicated in a multicenter study. If these findings are replicated, current prescreening questions before surgery may need to be changed and physicians may also want to be more careful when evaluating their female patients before prescribing penicillin for them, he noted.

“Primary care providers may want to key in on female patients and screen them a little bit further. The data are not firm. This is a preliminary result but it might lend itself to more research,” said Dr Mahr. “Maybe just plain simple chromosomes, X or Y, may tell us that you need to do a greater history on drug allergy.”

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