D1.296 - Nasal Adrenaline Spray vs Adrenaline Auto-Injectors: When Will People Act?

Delays in administration of adrenaline auto-injectors (AAIs) during anaphylaxis remains a major contributor to severe or fatal outcomes. Hesitation can arise from fear of needles, uncertainty about symptom thresholds, or lack of confidence in device use. A nasal adrenaline spray (NAS) offers an alternative that may reduce hesitation and promote earlier treatment. This study explored the symptom levels at which adults and caregivers expect they would administer an AAI or a NAS in an emergency.

60 participants from the UK completed the study: 30 adults (20 with known severe allergy) and 30 caregivers (20 caring for children with known severe allergy). The participants simulated, or watched someone simulate, two administrations with both an AAI and a NAS training devices and watched the official instruction videos. Participants were asked: “How long would you wait from getting symptoms to using the device?” and then indicated the earliest symptom level at which they would act, across five escalating severity levels:

1 – skin itching

2 – skin itching + nausea

3 – skin itching + nausea + coughing

4 – skin itching + nausea + coughing + trouble breathing

5 – skin itching + nausea + coughing + trouble breathing + swelling of lips/tongue, weak pulse and vomiting

Outcomes were compared using a paired Wilcoxon signed-rank test.

The participants responded they would administer a NAS at a significantly earlier level of symptoms compared with an AAI (NAS median level = 3, AAI median level = 4, p < 0.001). The NAS prompted action earlier for both injection-experienced and injection-naïve participants. Participants indicated greater hesitation with the AAI, where more would wait until severe respiratory symptoms or systemic compromise before acting: 55% would wait until level 4 or 5 before using an AAI, and 3% reported they would never use an AAI.

Participants reported that they would use a NAS significantly earlier compared to an AAI. This aligns with expert guidance that adrenaline should be administered at the first signs and symptoms of anaphylaxis occur. Delays in treatment with adrenaline can place patients experiencing anaphylaxis at significant risk. These findings highlight the need for meaningful dialogue between clinicians and patients to help them recognise reactions early.