The Effect of Pollen Season on Subcutaneous Allergen Immunotherapy Reactions

Subcutaneous allergen immunotherapy (SCIT) is a widely used and effective treatment modality for allergic rhinoconjunctivitis and asthma. SCIT starts with a build-up phase during which a patient receives frequent, escalating doses of the allergens they are allergic to until they reach a predetermined maintenance dose. This is followed by a maintenance phase during which the allergen dose is kept constant and administered at greater intervals. Maximum clinical improvement is generally not seen until a patient is in the maintenance phase. Anecdotal evidence of possible reactions to SCIT administered during a patient's pollen season has led to dosage freezes during a patient's pollen season which extends the length of the build-up phase by many months. Prolonging the buildup phase increases the time required to obtain maximal benefit from SCIT, and at the same time, can decrease patient compliance with therapy due to the prolonged period of time when frequent injections are required. The aims of this study are to determine if adverse reactions to pollen SCIT are increased if doses are increased during pollen season.