When assessing clients for evidence of a penicillin allergy, which of the following symptoms may not be considered to be a true hypersensitivity reaction?
A. Wheezing
B. Nausea
C. Urticaria
D. Angioneurotic edema
Correct Answer: B. Nausea
GI disturbances such as nausea are usually caused by direct irritation or overgrowth of gram-positive bacteria or yeasts and are not indicative of a true penicillin allergy. Anaphylaxis, characterized by symptomatic hypotension with associated dyspnoea, urticaria, and possibly gastrointestinal (GI) symptoms, is the most severe manifestation of IgE-mediated drug allergy. It is most common after parenteral drug administration and is rare with oral or cutaneous exposure.
Option A: Anaphylaxis results when antigen-specific IgE is present on mast cells and systemic exposure to antigen occurs, cross-linking the IgE. This results in the simultaneous degranulation of large numbers of mast cells.
Option C: Mast cells contain histamine and other vasoactive mediators. Their sudden release, due to either an IgE-mediated anaphylactic reaction or a similar non-IgE-mediated reaction (referred to as an “anaphylactic” reaction), results in a sudden drop in blood pressure and blood volume, flushing, itching, and potentially respiratory compromise, bowel edema, and potential death
Option D: If a patient has exhibited signs of a true allergic reaction, re-exposure to penicillin or related antibiotics can trigger life-threatening anaphylaxis. It has been estimated that up to 60% of penicillin-allergic patients will experience another allergic event if given the drug again. However, new data suggest that this rate is less than 2%.