- Patients who report antibiotic allergies often receive antibiotics that are less effective against the infections they may have, or are associated with higher toxicity risk and/or cost than the standard therapy.
- The majority of patients who report antibiotic allergies do not have true IgE-mediated allergic reactions to those drugs. Therefore, careful assessment of the reported reaction is needed to determine the risk for cross-reactivity and inform appropriate selection of therapy.
- True IgE-mediated reaction consists of urticaria (hives), angioedema (swelling), respiratory distress, vomiting, hypotension, or other findings of anaphylaxis.
- Amoxicillin and Ampicillin are associated with development of a delayed maculopapular rash in ~5-10% of patients who receive these drugs. These reactions are not IgE-mediated; careful history should be obtained to differentiate from an IgE-mediated reaction.
- Refer to the Inpatient Beta-Lactam Allergy Guideline for evaluation and management of patients with a documented beta-lactam allergy.
Reference: Weiss, ME, et al. Drug allergy: an updated practice parameter. Ann Allergy Asthma Immunol 2010;105:273.e1-273.e78