Diagnosis and Clinical Management of Drug Allergies in Obstetrics and Gynecology: An Expert Review.
Review
Overview
abstract
Drug allergies, specifically antibiotic allergies, are frequently encountered in obstetrics and gynecology as10% of the United States population reports a penicillin allergy. This poses a particular challenge to the obstetrician-gynecologist as beta-lactam antibiotics are indicated as first-line therapy for the treatment and prevention of most specialty-specific infections. Alternative antibiotic use in the setting of a reported allergy, is not benign and has been associated with increased cesarean delivery, endometritis, wound complications, and increased lengths of hospital stay in pregnant patients, increased Group B Streptococcus sepsis, neonatal length of stay and neonatal lab draws in neonates born to allergic patients and increased surgical site infections in gynecologic patients. Furthermore, alternative antibiotic use leads to increased antibiotic resistance, toxicity and healthcare cost. . Administration of antibiotics in a patient with a history of a Type I immediate hypersensitivity reaction, however, poses the risk of anaphylaxis with repeat exposure. Fortunately, over 90% of patients who report a penicillin allergy are not truly allergic and would tolerate penicillins if administered. This can be due to either mislabeling of the index reaction as an allergy (when it was due to a drug intolerance or a viral exanthem) or due to waning Immunoglobulin E-mediated immunity over time. Given this, allergy evaluation is widely recommended, even in pregnancy. Allergy evaluation involves a detailed patient history and when appropriate allergy testing with skin testing and/or oral challenge. These tools when used appropriately have been found to be safe and effective in gravid as well as non-gravid individuals and result in increased use of first line antibiotics. Furthermore, even in the setting of a true penicillin allergy, cross-reactivity with cephalosporins is extremely low and estimated at 2-3% among patients with a verified penicillin allergy and significantly lower than this among patients with an unverified penicillin allergy. Guidelines support routine use of cephalosporins without testing or additional precautions in patients with an unverified nonanaphylactic penicillin allergy as well as routine use of structurally dissimilar cephalosporins (specifically ancef) even in patients with an anaphylactic penicillin allergy. In cases where there is no appropriate alternative antibiotic than to the one which the patient is allergic such as with syphilis in a penicillin allergic pregnant patient, desensitization can be performed. This process involves temporary induction of drug tolerance through exposure of small amounts of the allergen until a therapeutic dose is achieved and has been safely performed in pregnancy. Desensitization requires expert supervision and is most often performed in the intensive care setting with a multidisciplinary team. The other two most common antibiotic allergies encountered in obstetrics and gynecology are to cephalosporins and metronidazole. Cephalosporin allergies are managed similarly to penicillin allergies with readily available skin testing and oral challenge. Skin testing for metronidazole allergy lacks sensitivity and specificity and thus oral challenge or desensitization procedure is the preferred approach for low risk and high-risk patients respectively. When it comes to drug allergies, and specifically antibiotic allergies, the role of the obstetrician-gynecologist is to identify patients with a reported allergy and to refer patients to a specialist for further evaluation as soon as possible. Allergy evaluation by means of a detailed patient history and allergy testing (skin testing and/or oral challenge) when indicated has been shown to be safe and effective and is an important part of antibiotic stewardship.
