Micro & Immunology · patient case question
With a patent airway and stable blood pressure, what is the appropriate management of the cutaneous reaction?
Patient case: Rash After Local Anesthetic in a Child
Patient: 10-year-old male
Chief Complaint: Restorative treatment on two mandibular molars.
Background: Healthy, no known allergies, no previous dental treatment requiring anesthesia. Immunizations current.
Medications: None
Vital Signs: Baseline: BP 100/62 mmHg · HR 86 bpm · RR 18 · T 98.4°F
Findings: Twenty minutes after administration of 2% lidocaine with 1:100,000 epinephrine, he develops a generalized raised urticarial rash over the trunk and arms, accompanied by nausea, one episode of vomiting, and loose stools. Mild expiratory wheeze is audible. Airway is patent, phonation is normal, and blood pressure remains stable at 98/60 mmHg.
Show answer and explanation
Correct answer: A. Administer a systemic antihistamine such as diphenhydramine
- A. Correct. For a reaction limited to skin and mild gastrointestinal symptoms with a stable airway and stable hemodynamics, an H1 antihistamine is appropriate. Discontinue the suspected agent, monitor closely, and arrange medical evaluation with allergy referral for definitive identification of the trigger.
- B. Incorrect. Intramuscular epinephrine is the immediate treatment for anaphylaxis — airway compromise, stridor, significant bronchospasm, or hypotension. His airway is patent and pressure is stable. That said, if his condition deteriorates at any point, epinephrine must be given without hesitation and takes absolute priority.
- C. Incorrect. Observation alone is inadequate when a systemic reaction with cutaneous, gastrointestinal, and respiratory features is already established.
- D. Incorrect. A topical agent cannot treat a systemic reaction involving multiple organ systems.
Note: Do not become complacent because vitals are currently stable. Biphasic anaphylaxis can recur hours after apparent resolution, which is why medical evaluation and a period of observation are part of the plan.
Practice Micro & Immunology questions Micro & Immunology study notes