Number of Subcutaneous Immunotherapy Injections Per Visit
In conventional immunotherapy schedules, one injection is given per visit, while cluster immunotherapy protocols involve 2 or more injections administered at a single visit, typically spaced 30 minutes apart. 1
Conventional Schedule
- Single injection per visit is the standard approach
- Visit frequency: 1 to 3 times per week during build-up phase
- Build-up phase duration: approximately 8 to 28 weeks
- Once maintenance is reached: injections every 2-4 weeks for inhalant allergens 1
Cluster Immunotherapy Schedule
- 2 or more injections per visit to accelerate reaching maintenance dose
- Injections typically given at 30-minute intervals (though longer intervals have been used in some protocols)
- Visit frequency: 1 to 2 times per week
- Can achieve maintenance dose in as brief as 4 weeks 1
Safety Considerations for Cluster Schedules
The cluster approach carries similar or increased risk of systemic reactions compared to conventional schedules 1. Optimal tolerance is associated with:
- Use of premedication (antihistamine)
- Use of depot preparation
- No more than 4 administrations per cluster
- Total of 4 to 6 clusters
- Administration of 1 to 2 clusters per week 1
Critical Safety Requirements (Regardless of Schedule)
- Antigens from different vials should NOT be combined in a single syringe 1
- Each injection must be given separately with its own syringe
- Patients must wait at least 30 minutes after all injections before leaving the medical facility 1
- Most serious systemic reactions develop within this 30-minute window, though delayed reactions can occur
Common Pitfall
Do not attempt to mix multiple allergen extracts into one syringe to reduce the number of injections—this violates established safety protocols and could lead to allergen degradation or unpredictable reactions 1.