Infant Anaphylaxis: A Diagnostic Challenge

Contemporary trends in anaphylaxis burden and healthcare utilisation in Western Australia: A linked data study

Background

Anaphylaxis is a growing public health problem in Australia. To determine the extent of the problem, we linked multiple health datasets to examine temporal trends in anaphylaxis events across the health system in Western Australia (WA).

Methods

We identified an anaphylaxis cohort from 1980 to 2020 using linked datasets from ambulance, emergency departments, hospital inpatients and deaths. Age-standardised anaphylaxis event rates were calculated from 2010 to 2020. Dataset-specific rates for anaphylaxis were also examined, to show differences in health care utilisation. Annual percent change in rates (2010-2019) were estimated using age-adjusted Poisson regression models.

Results

A total of 19 140 individuals (mean age 31 years; 51% female) experienced 24 239 anaphylaxis events between 2010 and 2020. From 2010 to 2019, the average annual percent increase (95% CI) in rates was 5.3% (4.8-5.8%), from 70.3 to 113.9, with rates reducing to 76.5/100 000 population in 2020. Adolescents and young adults aged 5-14 years and 15-24 years had the greatest increase of 6.9% (5.6-8.1%) and 6.8% (5.6-8.0) respectively, with those over 25 years increasing by approximately 5% per year and children 1-4 years showing the lowest annual increase of 2.6% (1.1-4.2%). The highest absolute rates were seen in under 1 year (269.7/100 000; 2019). There has been an acceleration of trends from 2015 to 2019, underpinned by large increases in 15-24 and 25-34 years. All databases, show similar increasing trends, with ambulance attendance (33.7 per 100 000), emergency presentation (89.8 per 100 000) and hospital admissions (46.2 per 100 000), for anaphylaxis highest in 2019. However, whilst ambulance and emergency presentations have grown by 8.9% (95%CI 7.9-9.8%) and 6.6% per year (95%CI 6.0-7.2%), respectively, hospitalisations appear to be steadying with only a 0.9% (95%CI 0.2-1.6%) yearly rise.

Conclusion

Rates of anaphylaxis continue to increase, with WA having higher rates than previous estimates for Australia. Whilst rates are still high in infants, lower trends in children compared to older ages may indicate better prevention of allergy. Results show more people experiencing anaphylaxis now receive care in emergency and ambulance, rather than hospital. Further exploration of the patient care journey through prehospital and inpatient care is required, to understand the changing health demands of people who experience anaphylaxis.

Different age groups present different clinics in anaphylaxis with children: one size does not fit all children

BACKGROUND

Childhood anaphylaxis presents with a heterogeneous clinic. Elicitors and epidemiologic factors associated with anaphylaxis differ with age, geographic location and lifestyle. This study aimed to determine the clinical features and age-specific patterns of childhood anaphylaxis in a single referral center in Turkey.

METHODS

We conducted a retrospective study of anaphylaxis in children aged between 0 and 18 years of age, attending an allergy department in a children's hospital.

RESULTS

A total of 95 children diagnosed with anaphylaxis were analyzed. Among all, 35.8% of the first anaphylaxis episodes occurred ininfancy and 57.9% in preschool age. Foods were the most common culprits (57.9%) and followed by drugs (15.8%). Patients with foodinduced anaphylaxis were younger in age (p < 0.001). Food-related anaphylaxis was most common with cow's milk (36.4%) and followed by tree nuts (20%). Cow's milk played a significant role as a trigger in infancy, and tree nuts as a trigger in preschoolers and school-age children. Mucocutaneous manifestations were almost universally present (94.7%), followed by respiratory compromise (56.8%), with gastrointestinal (55.8%), cardiovascular (9.5%), and neurologic (4.2%) symptoms being less common. Respiratory and cardiovascular system-related symptoms were found more frequently in school-age children (p = 0.02 and p = 0.014, respectively). The severity of anaphylaxis was higher in school-age children (p = 0.015).

DISCUSSION

Findings reveal that children diagnosed with anaphylaxis differ in terms of etiological and clinical findings according to age groups. This difference shows the dynamically changing clinic of anaphylaxis over time and the importance of evaluating childhood anaphylaxis according to age groups.

Impact of public health interventions for food allergy prevention on rates of infant anaphylaxis

BACKGROUND

Eleven percent of Australian infants have confirmed food allergy. We hypothesized earlier introduction may lead to higher rates of infant anaphylaxis, irrespective of whether the overall rate of food allergy in the population was ultimately reduced.

OBJECTIVE

To determine whether a public health campaign, targeting earlier introduction of allergenic foods, affected rates of infant anaphylaxis.

METHODS

Data were obtained from St John Ambulance (SJA) Western Australia and Western Australian emergency departments (ED) on infant (≤12 months) anaphylaxis over a 5-year period (July 1, 2015 to June 30, 2020). Adrenaline administration data were collected in the SJA dataset. Poisson regression was undertaken to assess trends in anaphylaxis over time. Segmented regression analysis was undertaken to assess differences in anaphylaxis rates before and after intervention.

RESULTS

The SJA and ED datasets included 172 and 294 events, respectively, coded as infant anaphylaxis. Rates of infant anaphylaxis increased over time for both SJA and ED datasets, with a 1-year increase rate ratio of 1.21 (95% confidence interval, 1.09-1.35; P value < .01) and 1.11 (95% confidence interval, 1.02-1.20; P = .01), respectively. Segmented regression indicated no significant difference in rates after intervention. Adrenaline was not coded as being administered in 109 of the 172 anaphylaxis events.

CONCLUSION

Rates of infant anaphylaxis increased over the 5-year reporting period; however, there was no clear increase related to the timing of the public health campaign implementation. Reported adrenaline use was suboptimal. Assessing rates of food allergy in all age groups is required to determine whether there has been an overall reduction in food allergy owing to the intervention.

Anaphylaxis viewed by experts: unmet needs

PURPOSE OF REVIEW

The purpose of the review is to identify unmet needs in the management of anaphylaxis, covering aspects such as epidemiology, diagnosis, treatment and prevention.

RECENT FINDINGS

Redefinition of clinical diagnostic criteria may allow a better identification of anaphylaxis. International diagnostic coding system improvement will be major step for future policies and epidemiological studies. Digital health can aid in managing anaphylaxis.

SUMMARY

Anaphylaxis is a medical emergency; current data show that frequently identification of the reaction, acute and long-term management, are not optimal. Therefore, there is a need to implement strategies to improve the situation. This review has identified unmet needs in anaphylaxis regarding aspects such as epidemiology, severity scoring, definition and diagnostic criteria, anaphylaxis in infants and toddlers, cofactors, biomarkers, long-term management, undertreatment and availability of epinephrine autoinjectors. Strategies focused on education, legislation, digital health and research are proposed.