Why is a patient with anaphylaxis presenting with symptoms of urticaria, wheezing, voice changes, and vomiting?

From the Guidelines

A patient with anaphylaxis presents with urticaria, wheezing, voice changes, and vomiting because these are classic manifestations of a severe, systemic allergic reaction affecting multiple organ systems, as described in the 2020 practice parameter update 1. Anaphylaxis is a life-threatening emergency caused by the massive release of inflammatory mediators, primarily histamine, from mast cells and basophils in response to an allergen. The skin symptoms (urticaria or hives) represent the most common manifestation, occurring in about 90% of cases. Respiratory involvement causes bronchospasm leading to wheezing, while laryngeal edema results in voice changes, both indicating potentially dangerous airway compromise. Gastrointestinal symptoms like vomiting occur due to smooth muscle contraction and increased vascular permeability in the digestive tract.

Key Symptoms and Treatment

• Urticaria: occurs in about 90% of cases
• Wheezing: due to bronchospasm
• Voice changes: due to laryngeal edema
• Vomiting: due to smooth muscle contraction and increased vascular permeability This multi-system involvement (cutaneous, respiratory, and gastrointestinal) meets the diagnostic criteria for anaphylaxis and requires immediate treatment with intramuscular epinephrine (0.3-0.5mg of 1:1000 concentration in adults, 0.15mg in small children) into the mid-outer thigh, which should be repeated every 5-15 minutes if symptoms persist, as recommended in the 2020 practice parameter update 1.

Additional Treatments

• Oxygen
• IV fluids
• Antihistamines: although they are often used as adjunctive therapy, they should not be administered before, or in place of, epinephrine, as stated in the study 1
• Corticosteroids: also used as adjunctive therapy, but their role in the acute management of anaphylaxis is limited due to their slow onset of action, as discussed in the study 1

From the FDA Drug Label

The signs and symptoms associated with anaphylaxis include flushing, apprehension, syncope, tachycardia, thready or unobtainable pulse associated with hypotension, convulsions, vomiting, diarrhea and abdominal cramps, involuntary voiding, airway swelling, laryngospasm, bronchospasm, pruritus, urticaria or angioedema, swelling of the eyelids, lips, and tongue. Through its action on alpha-adrenergic receptors, epinephrine lessens the vasodilation and increased vascular permeability that occurs during anaphylaxis, which can lead to loss of intravascular fluid volume and hypotension Through its action on beta-adrenergic receptors, epinephrine causes bronchial smooth muscle relaxation and helps alleviate bronchospasm, wheezing and dyspnea that may occur during anaphylaxis Epinephrine also alleviates pruritus, urticaria, and angioedema and may relieve gastrointestinal and genitourinary symptoms associated with anaphylaxis

The patient with anaphylaxis is presenting with symptoms of urticaria, wheezing, voice changes (likely due to laryngospasm), and vomiting because these are common signs and symptoms associated with anaphylaxis, as described in the drug label 2 and 2.

• Urticaria and angioedema are skin symptoms that occur due to increased vascular permeability during anaphylaxis.
• Wheezing and bronchospasm are respiratory symptoms that occur due to smooth muscle contraction in the airways during anaphylaxis.
• Vomiting is a gastrointestinal symptom that may occur during anaphylaxis due to the effects of the allergic reaction on the stomach and intestines.
• Voice changes can occur due to laryngospasm, which is a symptom of anaphylaxis that can cause airway swelling and obstruction.

From the Research

Symptoms of Anaphylaxis

• Urticaria, difficulty breathing, and mucosal swelling are the most common symptoms of anaphylaxis, as stated in the study 3
• The patient's symptoms of urticaria, wheezing, voice changes, and vomiting are consistent with anaphylaxis, which can present with a range of symptoms including respiratory, cardiovascular, and gastrointestinal manifestations 3, 4
• Voice changes can be a symptom of anaphylaxis due to mucosal swelling and airway obstruction 3

Pathogenesis of Anaphylaxis

• Anaphylaxis is a life-threatening systemic reaction, normally occurring within one to two hours of exposure to an allergen 3
• The exact mechanism of anaphylaxis is complex and involves the release of immunomodulators, including histamine, which can cause blood vessels to dilate and smooth muscle to contract 5

Diagnosis and Management of Anaphylaxis

• The diagnosis of anaphylaxis is primarily clinical, based on the presence of characteristic symptoms and signs 3, 4
• Epinephrine is the first-line treatment for anaphylaxis, and early administration is critical to prevent a potentially fatal outcome 3, 6, 5
• Antihistamines and corticosteroids may be used as adjunctive treatments, but their role in anaphylaxis management is still being studied 6, 5

Urticaria and Anaphylaxis

• Urticaria is a common symptom of anaphylaxis, and can also occur as a separate condition, such as chronic spontaneous urticaria (CSU) or chronic inducible urticaria (CIndU) 7
• The management of urticaria aims for the complete control and absence of its signs and symptoms, and may involve the use of antihistamines, corticosteroids, and other treatments 7