From the Guidelines
Yes, patients receiving immunotherapy for allergies can generally use antihistamines as needed (PRN) for symptom relief, as they can help manage breakthrough allergy symptoms without interfering with the long-term benefits of immunotherapy 1. Antihistamines like cetirizine (10mg daily), loratadine (10mg daily), or fexofenadine (180mg daily) can be taken to provide temporary symptom relief by blocking histamine receptors. However, patients should avoid taking antihistamines for 24-48 hours before scheduled immunotherapy appointments, as they may mask early signs of potential reactions to the treatment.
It's also important to inform your allergist about any antihistamine use, as they may need to adjust your immunotherapy protocol accordingly. While antihistamines provide temporary symptom relief, immunotherapy works differently by gradually desensitizing the immune system to specific allergens over time. These treatments work through complementary mechanisms, making it safe to use both simultaneously in most cases. According to the guidelines, antihistamines can be used on an intermittent basis, such as for episodic allergic rhinitis, and are generally effective in reducing rhinorrhea, sneezing, and itching associated with allergic rhinitis 1.
Some key points to consider when using antihistamines for symptom relief during immunotherapy include:
- Second-generation antihistamines, such as fexofenadine, loratadine, and desloratadine, are generally preferred over first-generation antihistamines due to their lower risk of sedation and anticholinergic effects 1.
- Antihistamines can be used in combination with other medications, such as intranasal corticosteroids, to provide optimal symptom relief 1.
- Patients should be instructed to use antihistamines as needed and to follow the recommended dosage instructions to minimize the risk of side effects 1.
Overall, the use of antihistamines as needed for symptom relief during immunotherapy can be a safe and effective way to manage breakthrough allergy symptoms, as long as patients are aware of the potential risks and benefits and follow the recommended guidelines 1.
From the Research
Immunotherapy and Antihistamine Use
- The use of antihistamines for symptoms in patients receiving immunotherapy for allergy is not directly addressed in the provided studies 2, 3, 4, 5, 6.
- However, it is mentioned that allergen immunotherapy has the potential to alter the allergic disease course after three to five years of therapy, and antihistamines are used to manage symptoms of allergic rhinitis 2, 3.
- Studies have shown that second-generation oral antihistamines and intranasal corticosteroids are the mainstays of treatment for allergic rhinitis, and combination therapy of intranasal corticosteroids and oral antihistamines may be effective in reducing symptoms 3.
- There is no evidence to suggest that using antihistamines as needed (PRN) would interfere with immunotherapy, but it is essential to follow the guidance of a healthcare professional 5, 6.
Safety and Efficacy of Immunotherapy
- Allergen immunotherapy is safe and effective in the treatment of stinging-insect hypersensitivity, allergic rhinitis, and allergic asthma 2, 5, 6.
- The therapy requires the immediate availability of a healthcare professional capable of recognizing and treating anaphylaxis, and patients should not be taking beta-adrenergic blocking agents when receiving immunotherapy 2.
- The administration of allergen immunotherapy should be done in a controlled environment, and patients should be monitored for adverse reactions 5, 6.
Management of Allergic Rhinitis
- The management of allergic rhinitis includes allergen avoidance, pharmacotherapy, and immunotherapy 3, 5.
- Pharmacotherapy options include oral and intranasal antihistamines, intranasal corticosteroids, oral and intranasal decongestants, oral and intranasal anticholinergics, and leukotriene receptor antagonists 3.
- The choice of treatment should be patient-specific, based on the type, duration, and severity of symptoms, comorbidities, prior treatment, and patient preference 3.