Characteristics of uniphasic and biphasic anaphylaxis in infants and young toddlers: An analysis of clinical signs, predictors and management.

BACKGROUND

Rates of anaphylaxis in early childhood are rising, yet there remains a paucity of data on age-specific presentations and outcomes. While prompt treatment is essential, symptoms can differ from older children. Observation after stabilization is routinely used; however, no infant and toddler-specific data guide the duration of monitoring. Identifying predictors of biphasic anaphylaxis could help guide observation times.

OBJECTIVE

To characterize symptoms of anaphylaxis in infants and toddlers, analyze predictors for biphasic anaphylaxis and get more insight into required observation times in this age group.

METHODS

Anaphylaxis cases aged 0-2 years presenting to a major Emergency Department (ED) were reviewed over two 5-year-periods. We analyzed clinical features, allergens, and management, comparing uniphasic and biphasic presentations.

RESULTS

Of 567,595 total ED presentations aged 0-16 years, 243 cases of 0-2-year-olds (infants/toddlers) presented with anaphylaxis (72/236,217 in 2003-2007; 171/331,378 in 2013-2017). Symptoms included urticaria (85.8%), angioedema (67.8%), wheeze/persistent cough (57.7%), vomiting (42.3%) and flushing (21.8%). Symptoms unique to infants/toddlers were pallor/hypotonia (33.5%) and persistent crying (13.8%). Biphasic anaphylaxis occurred in 4.6%, was exclusively food-induced and more common among infants (p = .048). Predictors for biphasic anaphylaxis were lower systolic blood pressure (p = .011), pallor/hypotonia (p = .046), use of fluids (p < .001), and greater severity (p = .014). Timeframe for recurrence of anaphylaxis was 70-330 min.

CONCLUSION

Increased awareness of age-specific symptoms is essential for timely recognition and optimal care of infant/young toddler anaphylaxis. Cardiovascular signs, fluid resuscitation, and reaction severity may help predict recurrent anaphylaxis in 0-2-year-olds and identify which patients need observation beyond 4 h versus those safe for earlier discharge.