Peanut-induced anaphylaxis in children and adolescents: Data from the European Anaphylaxis Registry.

BACKGROUND: Peanut allergy has a rising prevalence in high-income countries, affecting 0.5%-1.4% of children. This study aimed to better understand peanut anaphylaxis in comparison to anaphylaxis to other food triggers in European children and adolescents. METHODS: Data was sourced from the European Anaphylaxis Registry via an online questionnaire, after in-depth review of food-induced anaphylaxis cases in a tertiary paediatric allergy centre. RESULTS: 3514 cases of food anaphylaxis were reported between July 2007 - March 2018, 56% in patients younger than 18 years. Peanut anaphylaxis was recorded in 459 children and adolescents (85% of all peanut anaphylaxis cases). Previous reactions (42% vs. 38%; p = .001), asthma comorbidity (47% vs. 35%; p < .001), relevant cofactors (29% vs. 22%; p = .004) and biphasic reactions (10% vs. 4%; p = .001) were more commonly reported in peanut anaphylaxis. Most cases were labelled as severe anaphylaxis (Ring&Messmer grade III 65% vs. 56% and grade IV 1.1% vs. 0.9%; p = .001). Self-administration of intramuscular adrenaline was low (17% vs. 15%), professional adrenaline administration was higher in non-peanut food anaphylaxis (34% vs. 26%; p = .003). Hospitalization was higher for peanut anaphylaxis (67% vs. 54%; p = .004). CONCLUSIONS: The European Anaphylaxis Registry data confirmed peanut as one of the major causes of severe, potentially life-threatening allergic reactions in European children, with some characteristic features e.g., presence of asthma comorbidity and increased rate of biphasic reactions. Usage of intramuscular adrenaline as first-line treatment is low and needs to be improved. The Registry, designed as the largest database on anaphylaxis, allows continuous assessment of this condition.

Oral peanut immunotherapy in children with peanut anaphylaxis.

BACKGROUND: The only treatment option for peanut allergy is strict avoidance. OBJECTIVE: To investigate efficacy and safety of oral immunotherapy (OIT) in peanut allergy. METHODS: Twenty-three children (age, 3.2-14.3 years) with IgE-mediated peanut allergy confirmed by positive double-blind, placebo-controlled food challenge (DBPCFC) received OIT following a rush protocol with roasted peanut for 7 days. If a protective dose of at least 0.5 g peanut was not achieved, patients continued with a long-term buildup protocol using biweekly dose increases up to at least 0.5 g peanut. A maintenance phase for 8 weeks was followed by 2 weeks of peanut avoidance and a final DBPCFC. Immunologic parameters were determined. RESULTS: After OIT using the rush protocol, patients tolerated a median dose of only 0.15 g peanut. Twenty-two of 23 patients continued with the long-term protocol. After a median of 7 months, 14 patients reached the protective dose. At the final DBPCFC, patients tolerated a median of 1 g (range, 0.25-4 g) in comparison with 0.19 g peanut at the DBPCFC before OIT (range, 0.02-1 g). In 2.6% of 6137 total daily doses, mild to moderate side effects were observed; in 1.3%, symptoms of pulmonary obstruction were detected. OIT was discontinued in 4 of 22 patients because of adverse events. There was a significant increase in peanut-specific serum IgG(4) and a decrease in peanut-specific IL-5, IL-4, and IL-2 production by PBMCs after OIT. CONCLUSION: Long-term OIT appears to be safe and of some benefit in many patients with peanut allergy. With an increase in threshold levels and a reduction of peanut-specific T(H)2 cytokine production, the induction of tolerance may be feasible in some patients.

The atopy patch test in the diagnostic workup of suspected food-related symptoms in children.

BACKGROUND: There is an increasing need to develop test instruments that make oral food challenges superfluous. OBJECTIVE: We sought to study the utility of atopy patch tests (APTs) in the diagnostic workup of food allergy. METHODS: We investigated 437 children (median age, 13 months; 90% with atopic dermatitis) referred for evaluation of suspected food allergy. Specific serum IgE (sIgE) measurements, skin prick tests (SPTs), APTs, and controlled oral food challenges were performed. RESULTS: We analyzed 873 oral challenges with cow's milk, hen's egg, wheat, and/or soy. One thousand seven hundred single APTs were performed. As a single parameter, the APTs showed the best specificity compared with sIgE measurements, SPTs, or both. Combining the APT with either the SPT or sIgE measurement resulted in improved sensitivity and specificity. Decision points for sIgE measurement and for the SPT showed lower values when combined with a positive APT result. Correctly bypassing an oral food challenge with combined testing, including APTs, only between 0.5% and 7% (99% predicted probability) and between 6% and 14% (using 95% predicted probability) of children would fulfill the criteria for avoiding an oral food challenge. CONCLUSION: Although the predictive capacity of the APT is improved when combined with sIgE measurement or the SPT, oral food challenges become superfluous in only 0.5% to 14% of study patients. In addition, the APT is time consuming and demands a highly experienced test evaluator. CLINICAL IMPLICATIONS: For daily clinical practice, the APT adds only a small predictive value to the standard SPT and sIgE measurement in the diagnostic workup of suspected food-related symptoms in our study population.

Proposal for a standardized interpretation of the atopy patch test in children with atopic dermatitis and suspected food allergy.

The interpretation of the atopy patch test (APT) to foods is not standardized. This study aimed to validate the reading of the APT in terms of the diagnostic accuracy of individual skin signs. Eighty-seven children (mean age 2.4 +/- 2.5 yr, range 0.5-13.5; 57 male) with atopic dermatitis (AD) and suspected food allergies underwent APT to cow's milk, hen's egg, wheat and soy. Twelve-millimetre Finn chambers were applied for 48 h, and results were read after 48 and 72 h. Skin changes were graded for erythema, induration, papule formation and 'crescendo' phenomenon (increase of skin sign severity from 48 to 72 h). Food allergy was assessed by double blind, placebo-controlled food challenges (DBPCFC). Sensitivity, specificity and predictive values were calculated for each skin signs in relation to challenge outcome. Of 165 DBPCFC children, 75 (45%) were positive. The combination of any skin induration plus papules (seven or more), or of moderate erythema plus any induration plus seven or more papules had a positive predictive value (PPV) and specificity for the challenge outcome of 100%; however, the sensitivity was low (8% and 15%). The best diagnostic accuracy for single signs was found for induration beyond the Finn chamber margin (PPV 88%, specificity 99%, sensitivity 9%) and presence of at least seven papules (PPV 80%, specificity 96% sensitivity 21%). Presence of both induration and of at least seven papules at 72 h were the APT skin signs with the greatest diagnostic accuracy for food allergy in children with AD.