What is the treatment for a 16-year-old female presenting with urticaria, wheezing, voice change, and vomiting after eating lunch, suggestive of an acute allergic reaction (anaphylaxis)?

From the Guidelines

This patient is experiencing anaphylaxis, a severe allergic reaction, and requires immediate treatment with epinephrine (adrenaline) 0.3mg (0.3mL of 1:1000 solution) administered intramuscularly in the mid-outer thigh, as recommended by the most recent guidelines 1. The patient's symptoms, including urticaria, wheezing, voice change, and vomiting, are consistent with anaphylaxis, a life-threatening condition that requires prompt treatment.

Treatment Approach

The first-line treatment for anaphylaxis is epinephrine, which should be administered without delay 1. After administering epinephrine, the patient should be placed in a supine position with legs elevated, unless she has respiratory distress. Supplemental oxygen should be provided if available, and IV access should be established for fluid resuscitation with normal saline.

Additional Medications

Additional medications, such as H1 antihistamines (diphenhydramine 25-50mg IV/IM) and H2 blockers (ranitidine 50mg IV or famotidine 20mg IV), may be used as adjunctive therapy, but should not be administered prior to, or in place of, epinephrine 1. Corticosteroids (methylprednisolone 125mg IV) may also be used, but their role in the acute management of anaphylaxis is limited due to their slow onset of action 1.

Monitoring and Follow-up

The patient's vital signs should be monitored continuously, and epinephrine should be repeated every 5-15 minutes if symptoms persist. The patient should be transported to an emergency department for observation for at least 4-6 hours, as biphasic reactions can occur 1.

Key Considerations

It is essential to note that epinephrine is the cornerstone of anaphylaxis management, and its administration should not be delayed 1. Antihistamines and glucocorticoids may be used as adjunctive therapy, but their role is secondary to epinephrine, and they should not be relied upon as the primary treatment for anaphylaxis 1.

From the FDA Drug Label

Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis. 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.

Antihistaminic For amelioration of allergic reactions to blood or plasma, in anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled, and for other uncomplicated allergic conditions of the immediate type when oral therapy is impossible or contraindicated.

The patient presents with symptoms of anaphylaxis, including urticaria, wheezing, voice change, and vomiting. The first line of treatment for anaphylaxis is epinephrine (IM) 2.

• Administer epinephrine (IM) as soon as possible.
• After the acute symptoms have been controlled, diphenhydramine (IV) can be used as an adjunct to epinephrine and other standard measures 3.

From the Research

Treatment Approach

The patient presents with symptoms of anaphylaxis, including urticaria, wheezing, voice change, and vomiting after eating lunch. The treatment approach for anaphylaxis is outlined in several studies 4, 5.

Immediate Treatment

• Intramuscular epinephrine is the immediate treatment for all patients with anaphylaxis 4.
• Intravenous epinephrine should be used in patients in shock, either as a bolus or infusion, along with fluid resuscitation 4.
• Airway obstruction must be recognized, and early intubation may be necessary 4.

Additional Treatment

• Antihistamines, such as second-generation antihistamines, may be used in addition to epinephrine, as they have been shown to be beneficial in anaphylaxis management 5.
• However, the use of corticosteroids in anaphylaxis should be revisited, as they may not be beneficial and may even be harmful 5.
• Diphenhydramine, a first-generation antihistamine, is not recommended due to its sedative effects and risk of toxicity in overdose 6, 7.

Disposition

• Disposition depends on patient presentation and response to treatment 4.
• Mandatory observation periods are not necessary, as biphasic reactions are difficult to predict and may occur outside of typical observation periods 4.