Symptoms, treatment, and main allergens
Urticaria was reported by 56 patients in the anaphylaxis group (39.2%) as being present during the initial reaction to the food, compared to only 17 patients in the non-anaphylaxis group (18.5%) (p-value< 0.0008). The symptom most frequently presented in the anaphylaxis group was abdominal pain (60.8%), followed by urticaria (49.0%). Other patients’ characteristics are shown in Table 1.
Most patients with anaphylaxis were treated with oral antihistamines (93.7%) and oral corticosteroids (69.2%); adrenaline intramuscular injection was administered only in 47.6% of them (Table 2).
When considering the most frequent food responsible for a positive OFC, the main group includes tree nuts (31.9%), followed by peanuts (27.7%) and eggs (11.1%) (Figure 1). As for tree nuts (Figure 1), cashew nuts were the most commonly one responsible for allergies (22.7% of this subgroup and 7.2% of the whole anaphylaxis group).
We assessed the different foods responsible for reactions during the OFC and found legumes (besides peanut) were those more frequently associated with anaphylactic reactions compared to non-anaphylactic ones (90.9% vs. 9.1%), while patients with a positive OFC to seafood, excluding fishes, reacted mainly without experiencing anaphylaxis (30.0% vs. 70.0%), as shown in Figure 2. Peanuts, the most common allergen associated with a positive OFC, were responsible for anaphylaxis in allergic patients in 70.8% of cases. As for tree nuts, almonds triggered anaphylaxis in every positive OFC; on the other hand, Brazil nuts, in the case of a positive OFC, were never associated with anaphylaxis (Figure 2).