Symptoms, severity and timing of reaction
Respiratory (92% vs 90%) and skin (91% vs 94%; p=0.009) were the organ systems most frequently affected in both subgroups. Gastro-intestinal symptoms were more common in peanut anaphylaxis (59% vs 50%; p=0.003) and there was no statistically significant difference for cardio-vascular involvement between subgroups (36% vs 35%).
According to the Ring&Messmer classification the majority of cases in both subgroups were labelled as severe anaphylaxis, however significantly more in the peanut cohort: grade III (65% vs 56%; p=0.001) and grade IV (1.1% vs 0.9%) (Table 1).
Death was recorded in 0.7% (n=3) in the peanut cohort, and in 0.3% (n=5) in the other food cohort. The 3 cases of fatal peanut anaphylaxis occurred in 2006, 2012 and 2013. They were all female teenagers, two of them had other food allergies/atopic disease, and stress was given as possible cofactor in one case. First line treatment was unknown in one case and provided by an emergency professional in the other two, but only one received adrenaline (i.m. and i.v.) as well as oxygen and i.v. fluid volume. Other confirmed food triggers causing fatal anaphylaxis were cow’s milk (2 cases), snail, and poppy seeds, whereas kiwi or hazelnut were suspected in another case.
Analysis of the interval between exposure and onset of symptoms revealed no differences between peanut and other food triggered anaphylaxis: 49% (n=226; specified for 366 out of 459 cases) and 48% (n=714; specified for 1219 out of 1503) respectively reacted within 10 minutes after exposure to the trigger, and another 18% (n=83) and 21% respectively (n=310) within 30 minutes. In both subgroups 6% of the patients reported a delayed reaction with an
interval of more than 1 hour.
The frequency of biphasic reactions was significantly higher for peanut anaphylaxis compared to other food triggers (10%, specified for n=404 out of 459, vs 4%, specified for n=1314 out of 1503; p=0.001) (Table 1). The second reaction occurred after more than 12 hours in 21% of the cases in both subgroups. For peanut anaphylaxis, there were no statistically significant differences between the biphasic and non-biphasic reactions in terms of age, reaction severity, and administration of adrenaline.