Although hospital admissions for food anaphylaxis increased over the past 20 years in the UK the case fatality rate more than halved, an analysis of national data has shown.

Hospital admission data for England, Scotland, Wales and Northern Ireland, from 1998 to 2018, were analysed. ICD-10 codes were used to identify cases of anaphylactic shock due to adverse food reactions. Deaths from anaphylaxis were determined from national registries.

Annual prescription data for adrenaline autoinjectors were obtained from the national prescribing authorities.

Over the study period, there were 101,891 admissions for anaphylaxis, 30,700 (30.1%) were coded as due to a food trigger. Admission rates increased over the 20-year period from 1.23 to 4.04 per 100,000 population per year, an annual increase of 5.7%.

The sharpest increase was seen in children under 15, from 2.1 to 9.2 admissions per 100,000 population per year, a year on year increase of 6.6%. By comparison, an annual increase of 5.9% was observed for those aged 15-59 and 2.1% for those 60 years and over.

Overall, the case fatality rate fell from 0.7% to 0.19% for confirmed fatal food anaphylaxis between 1998 and 2018. Deaths rates were low in young children, peaked in the teenage years and then declined throughout adulthood.

The decline in case fatality rates over the 20-year study period may have been due in part to improved recognition and management.

The researchers found that prescribing of adrenaline autoinjectors had increased by 336% between 1998 and 2018, a year on year increase of 11%.

In around a quarter of fatal cases the food trigger could not be identified. Where it was, 46% of deaths were found to have been triggered by peanut or tree nut, cow’s milk was responsible for 26% of deaths in children and 5% in adults.

The authors comment that more education is needed to highlight the specific risks posed by cow’s milk to individuals who are allergic to it.

The take home messages for me are to be more vigilant with respect to children who are not growing out of milk allergy, and to reinforce the importance of adrenaline autoinjectors, allergen avoidance and proper training for both patients and carers.

Dr Peter Saul