A nurse is assessing a patient who experienced a severe allergic reaction to peanuts 15 minutes ago. Which assessment finding would be the MOST concerning and require immediate intervention?

Stridor indicates laryngeal edema and upper airway obstruction, a life-threatening emergency requiring immediate intervention. Other options are symptoms of anaphylaxis but do not pose an immediate life threat.

Clinical Reasoning and Priority Setting in Anaphylaxis

When a patient presents with a severe allergic reaction, the nurse must rapidly triage assessment findings based on the principle of airway, breathing, and circulation (ABCs). The most concerning finding is stridor accompanied by difficulty speaking, as these are direct indicators of impending airway compromise. In the spectrum of anaphylactic reactions, the progression from mild symptoms to life-threatening multisystem involvement can occur precipitously, with airway edema posing the most immediate threat to life ^[1].

Pathophysiology and Clinical Significance of Stridor
Stridor is a high-pitched, turbulent sound generated by airflow through a narrowed upper airway, typically at the level of the larynx or trachea. In anaphylaxis, massive histamine release causes rapid angioedema of the laryngeal and pharyngeal tissues. When a patient exhibits stridor and can only speak with difficulty, this signals that the airway lumen is critically reduced. The work of breathing escalates, and without immediate intervention, total airway occlusion and respiratory arrest are imminent. This aligns with the emphasis in emergency protocols on early recognition of airway compromise as a trigger for immediate epinephrine administration and airway stabilization ^[1]. Notably, anaphylaxis can present with stridor that mimics other conditions like severe croup, which underscores the necessity for vigilant assessment and a high index of suspicion ^[2].

Analysis of Other Assessment Findings
While the other options represent true manifestations of anaphylaxis and require prompt treatment, they do not signal immediate, life-threatening airway loss in the same way stridor does.

- Generalized urticaria and pruritus (Option 2) are dermatologic signs of massive mast cell degranulation. They are distressing and confirm a systemic reaction but do not directly threaten the airway or circulation in the immediate term.
- Nausea and abdominal cramping (Option 3) result from histamine's effect on the gastrointestinal smooth muscle. These are common in food-induced anaphylaxis but are secondary to airway and hemodynamic concerns in priority.
- Swelling of the lips and eyelids (Option 4), or angioedema, is a concerning sign of a systemic reaction and can be a precursor to laryngeal edema. However, it is the progression of this swelling to the tongue, pharynx, and larynx—manifesting as stridor and dysphonia—that constitutes the airway emergency.

Immediate Nursing Intervention
The presence of stridor necessitates the highest-priority intervention: securing the airway and administering intramuscular epinephrine without delay. Epinephrine acts as a physiologic antagonist to the mediators of anaphylaxis, causing vasoconstriction, which reduces laryngeal edema, and bronchodilation. Emergency protocols dictate that recognition of anaphylaxis with airway involvement should lead to immediate epinephrine injection, preparation for potential advanced airway management, and rapid transfer to a higher level of care ^[1]. The case reports of anaphylaxis presenting with acute stridor further reinforce that rapid administration of intramuscular adrenaline is the critical, life-saving action that leads to recovery ^[2].