Desensitization in patients with beta-lactam drug allergy.

BACKGROUND

Patients with a history of beta-lactam antibiotic allergy are often admitted to the hospital with severe or life-threatening infections requiring beta-lactam antibiotics. Strict avoidance of beta lactams to such patients may prevent them from getting adequate coverage and can lead to an increase in the use of alternative antibiotics, which can predispose to antibiotic resistance. Past studies revealed a lower incidence of pen allergy then patients' histories suggest. Fortunately today, there are three options for patients presenting with a history of beta-lactam allergy. Penicillin skin testing, beta-lactam challenge or beta-lactam desensitization. Recently Pre Pen has been FDA re-approved and when combined with Pen G is a valid way to determine if patients are able to tolerate beta-lactam antibiotic. When these agents are not available one must decide about desensitization or challenge. When a patient has a positive penicillin skin test, desensitization or beta-lactam avoidance are the only options. This paper reviews the safety of beta-lactam desensitization.

OBJECTIVE

To perform a chart review on patients desensitised with beta lactam to determine if desensitizations can be performed safely without minimal complications.

METHODS

A retrospective chart review was performed on allergy and immunology inpatient consultations for beta-lactam desensitization between September 2003 and August 2006 at the Cedars-Sinai Medical Centre in Los Angeles. Patient data and outcomes of desensitization were analysed.

RESULTS

A total of 13 intravenous desensitizations were performed on 12 patients. The patients consisted of eight females and four males with an average age of 65 years. Age range was 36-92 years old. All 13 intravenous desensitizations were completed without complications. No patient required a slower rate of desensitization or discontinuance of the desensitization. Patients were able to tolerate the initial therapeutic dose of their beta-lactam antibiotic and were then able to complete full therapeutic courses of their antibiotic.

CONCLUSION

Beta-lactam antibiotic sensitivity continues to present a challenging problem for physicians. Patients with drug resistant infections who are unable to obtain skin testing or who test positive to skin tests may need either a challenge or desensitization. Desensitization, saved for those with a convincing beta-lactam hypersensitivity history is often the choice of last resort given the associated cost and risk of anaphylaxis. However, once desensitization is complete, patients are usually able to tolerate full doses of antibiotics for full treatment length with minimal side effects.