From the Guidelines
For a patient experiencing lip swelling and itching from a food allergen without airway compromise, the most appropriate emergency treatment is to administer an oral antihistamine, such as diphenhydramine (Benadryl) 25-50 mg for adults or 1 mg/kg for children (maximum 50 mg), and closely monitor the patient for at least 4-6 hours, as allergic reactions can progress, as recommended by the guidelines for the diagnosis and management of food allergy in the United States 1.
The patient should be instructed to remove the allergen by stopping consumption of the triggering food and rinse the mouth if needed. Applying cold compresses to the lips can help reduce swelling, and if available, topical antihistamine creams may provide additional relief for itching. It is essential for the patient to avoid scratching to prevent further irritation. These measures work by blocking histamine receptors, reducing the inflammatory response triggered by the allergen.
If symptoms worsen, develop into difficulty breathing, throat tightness, or other systemic symptoms, the patient should seek emergency medical care immediately, as this may indicate progression to anaphylaxis requiring epinephrine. Patients with known food allergies should be advised to carry an epinephrine auto-injector for future reactions, as emphasized in the guidelines for the diagnosis and management of food allergy in the United States 1 and supported by the recommendations for epinephrine for first-aid management of anaphylaxis 1.
Key considerations in the management of food-induced anaphylaxis include:
- Dosing with IM epinephrine followed by transfer to an emergency facility for observation and possible further treatment
- Observation for 4 to 6 hours or longer based on severity of the reaction
- Education for patient and family on allergen avoidance, early recognition of signs and symptoms of anaphylaxis, and anaphylaxis emergency action plan implementation
- Epinephrine auto-injector prescription and training provided at the time of discharge
- Continuation of adjunctive treatment after patient discharge, including H1 antihistamine, H2 antihistamine, and corticosteroid, as recommended by the guidelines for the diagnosis and management of food allergy in the United States 1.
From the FDA Drug Label
Emergency treatment of allergic reactions (Type 1), including anaphylaxis Adults and Children 30 kg (66 lbs) or more: 0.3 to 0.5 mg (0.3 to 0.5 mL) intramuscularly or subcutaneously into anterolateral aspect of the thigh every 5 to 10 minutes as necessary Children 30 kg (66 lbs) or less: 0.01 mg/kg (0.01 mL/kg), up to 0.3 mg (0.3 mL), intramuscularly or subcutaneously into anterolateral aspect of the thigh every 5 to 10 minutes as necessary
The emergency treatment for a patient with lip swelling and itching after an allergic reaction to a food allergen, with no airway compromise, is epinephrine (IM). The dosage is:
- 0.3 to 0.5 mg for adults and children over 30 kg, administered intramuscularly or subcutaneously into the anterolateral aspect of the thigh, every 5 to 10 minutes as necessary.
- 0.01 mg/kg (up to 0.3 mg) for children under 30 kg, administered intramuscularly or subcutaneously into the anterolateral aspect of the thigh, every 5 to 10 minutes as necessary 2.
From the Research
Emergency Treatment for Anaphylaxis
The patient's symptoms of lip swelling and itching after eating a cookie with ants suggest an allergic reaction, potentially anaphylaxis. Given that there is no airway compromise, the treatment should focus on relieving the symptoms and preventing further progression.
First-Line Treatment
- Epinephrine is considered the first-line treatment for anaphylaxis, as stated in the study by 3. It is essential to administer epinephrine promptly to prevent a potentially fatal outcome.
- The study by 4 emphasizes the importance of epinephrine over antihistamines, as epinephrine acts rapidly and can relieve symptoms of anaphylaxis, including airway obstruction, hypotension, and shock.
Additional Treatments
- Antihistamines, such as diphenhydramine, may be used in addition to epinephrine to relieve symptoms, as suggested by the study by 5. However, antihistamines should not replace epinephrine as the primary treatment.
- Corticosteroids, such as glucocorticoids, are not recommended as a first-line treatment for anaphylaxis, as there is limited evidence to support their use, according to the study by 6.