PURPOSE OF THE STUDY.
To evaluate if it is adequate to identify clinically significant penicillin allergy by using only the commercially available penicilloyl-poly-lysine and penicillin skin tests followed by an oral amoxicillin challenge.
A total of 500 sequential subjects with a history of penicillin allergy evaluated at the Kaiser Permanente Health Care Program were included in this study. A potential case of allergy to penicillin was defined as any penicillin class antibiotic allergy entry in the drug allergy section of the electronic medical record. The mean age of participants was 40.7 years, with a range of 1.1 to 93.4 years (25% were 14 years of age or younger).
Subjects were evaluated by skin testing with penicilloyl-poly-lysine and penicillin performed by registered nurses. If the skin-prick test was positive (wheal >5 mm in diameter), no intradermal testing was done. If it was negative, then intradermal testing was performed. Patients with positive testing were told to continue to avoid penicillins. All patients who had negative skin tests underwent an oral amoxicillin challenge, followed by 1 hour of observation.
Only 4 subjects (0.8%) had a positive skin test result, all with intradermal testing. Only 4 persons (0.8%) had an acute objective oral amoxicillin challenge reaction. There were 15 patients (3.0%) who had subjective oral challenge reactions, either acute transient itching or dizziness. Eleven (73.3%) had multiple drug intolerance syndrome, and none had severe reactions or objective signs. In 90 days of follow-up, 68 subjects (13.6%) who had negative testing were exposed to 88 courses of penicillins; new reactions were reported after 4 courses (4.5%), 3 (75%) occurring in subjects with multiple drug intolerance syndrome.
This study found that penicillin skin testing, using only penicilloyl-poly-lysine and penicillin, followed by oral amoxicillin challenge if negative on skin testing can safely identify clinically significant immunoglobulin E–mediated penicillin allergy.
This study reinforces previous reports that very few patients with a history of penicillin allergy have positive testing, and of those with negative testing the likelihood of a reaction is extremely small, with a minimal chance of a severe reaction. It demonstrates that skin testing using only commercially available penicilloyl-poly-lysine and penicillin skin tests followed by an oral amoxicillin challenge is a safe and effective way to evaluate patients with reported penicillin allergy. The authors comment that allergists in the United States should be testing and challenging hundreds of thousands of persons annually, because there is widespread overreporting of penicillin allergy, with >20 million Americans having a history of an allergy to penicillin. Referral for penicillin allergy testing would allow more appropriate use of relatively narrow-spectrum penicillin class antibiotics.
- Copyright © 2013 by the American Academy of Pediatrics