What are the treatment options for allergies?

Treatment of Allergy

Allergen avoidance is the first-line treatment for all allergic conditions, followed by pharmacotherapy tailored to symptom severity, with epinephrine as the only first-line treatment for anaphylaxis. 1, 2

Allergen Avoidance

• Strict avoidance of identified allergens is the cornerstone of allergy management and should be implemented before or alongside pharmacotherapy. 1
• For food allergies specifically, there are no medications to prevent allergic reactions, making avoidance the only preventive strategy. 1
• Patients and caregivers require education on reading food labels, recognizing precautionary labeling (e.g., "may contain traces"), and avoiding products with such warnings. 1
• For indoor allergens (dust mites, pet dander), environmental control measures are practical and effective, though pollen avoidance may require significant lifestyle modifications. 3, 4
• Nutritional counseling and regular growth monitoring are essential for children with food allergies to prevent deficiencies from dietary restrictions. 1

Pharmacotherapy for Non-Anaphylactic Allergic Reactions

Mild Symptoms (localized hives, mild nasal symptoms)

• Second-generation non-sedating H1 antihistamines are preferred (e.g., loratadine 10 mg once daily) due to reduced sedation and cognitive impairment compared to first-generation agents. 5
• Use antihistamines as needed for symptom relief in mild, intermittent allergic reactions. 5

Moderate Symptoms (persistent allergic rhinitis)

• Intranasal corticosteroids (INCS) are the preferred monotherapy for consistent allergic rhinitis symptoms. 5
• Intranasal antihistamines (e.g., azelastine) are equal or superior to oral antihistamines for seasonal allergic rhinitis and can be used as first-line treatment. 5
• Leukotriene receptor antagonists may be added for additional symptom control. 1, 5

Severe Symptoms (persistent, uncontrolled)

• Combination therapy with INCS plus oral antihistamine and/or leukotriene receptor antagonist is recommended for severe allergic rhinitis. 5
• For allergic asthma, inhaled corticosteroids are the preferred controller medication, with medium-to-high doses plus long-acting beta agonists for severe cases. 5
• Biologics (e.g., omalizumab) should be considered for severe allergic asthma with documented IgE sensitization when other therapies fail. 5

Emergency Treatment of Anaphylaxis

First-Line Treatment (Immediate)

• Epinephrine intramuscular (IM) is the only first-line treatment with no substitute. 2, 5, 6, 7
• Administer epinephrine 0.01 mg/kg (maximum 0.5 mg for adults, 0.3 mg for children) IM into the anterolateral thigh immediately upon recognition of anaphylaxis. 1, 6
• Repeat every 5-15 minutes if symptoms persist or recur. 1
• Place patient in recumbent position with lower extremities elevated if tolerated. 1

Common pitfall: Using antihistamines as primary treatment instead of epinephrine is the most common error and significantly increases risk of life-threatening progression. 2

Second-Line/Adjunctive Treatment (After Epinephrine)

• H1 antihistamines: Diphenhydramine 1-2 mg/kg (maximum 50 mg) IV or oral for itching and urticaria. 1, 2, 5
• H2 antihistamines: Ranitidine 1-2 mg/kg (maximum 75-150 mg) oral or IV; combination of H1 and H2 antihistamines works better than either alone. 1, 2
• Corticosteroids: Prednisone 1 mg/kg (maximum 60-80 mg) orally or methylprednisolone IV to prevent biphasic reactions, though evidence for this is limited. 1, 2
• Bronchodilators: Albuterol via metered-dose inhaler (4-8 puffs for children, 8 puffs for adults) or nebulized solution for respiratory symptoms. 1
• Glucagon: For refractory hypotension, especially in patients on beta-blockers; 20-30 μg/kg for children or 1-5 mg for adults. 1, 2

Post-Emergency Management

• Continue diphenhydramine every 6 hours for 2-3 days after discharge. 1, 2
• Continue ranitidine twice daily for 2-3 days. 1
• Continue prednisone daily for 2-3 days. 1
• Prescribe two epinephrine auto-injectors with proper training for all patients at risk of recurrent anaphylaxis. 1, 2, 5
• Develop an emergency action plan and provide education on allergen avoidance. 2, 5, 7
• Refer to an allergist for comprehensive evaluation. 1, 5, 7

Allergen Immunotherapy

• Consider subcutaneous or sublingual immunotherapy for patients with persistent symptoms despite optimal pharmacotherapy and documented IgE sensitization to clinically relevant allergens. 1, 5, 8
• Immunotherapy is effective for allergic rhinitis, allergic asthma, and insect venom allergies. 1, 5, 8
• Allergen immunotherapy is NOT recommended for IgE-mediated food allergies outside of research settings due to safety concerns and lack of proven long-term tolerance. 1
• Oral immunotherapy (OIT) and sublingual immunotherapy (SLIT) for food allergies remain experimental and are not FDA-approved; they can cause anaphylaxis during treatment. 1

Important caveat: Immunotherapy must be administered in settings equipped to recognize and treat anaphylaxis, with epinephrine and resuscitation equipment immediately available. 1

Monitoring and Follow-Up

• Observe patients for 4-12 hours after anaphylaxis for potential biphasic reactions, with longer observation for those with risk factors for severe anaphylaxis. 7
• Follow-up testing for food allergies depends on the specific allergen, patient age, and clinical history; annual testing may be appropriate for some allergens. 1
• Regular growth monitoring is mandatory for children with food allergies on elimination diets. 1