Abstract Objective Evaluate biomarkers capable of safely guiding Yellow fever vaccine (YFV) vaccination among individuals suspicious of hen's egg allergy, and identify factors associated with a higher risk for adverse events after immunization (AEAI). Methods Patients underwent skin prick test (SPT) for standardized allergens: whole egg, egg white, egg yolk; YFV (1:10 dilution; Biomanguinhos-Fiocruz), and intradermal test (IDT; YFV 0.02 mL, 1:100 dilution) and positive and negative controls. Serum levels of specific IgE (sIgE) for a whole egg, egg white, egg yolk, egg albumin, ovomucoid, lysozyme, and conalbumin (ImmunoCap®; ThermoFisher®) were obtained. Patients sensitized to YFV were submitted to YFV desensitization, and those negatives received YFV (0.5mL) and remained under surveillance for at least one hour. Results 103 patients were enrolled, 95% under 12 years old. 71% (81/103) of patients had reactions: 80% immediate, 11% mixed, and 9% delayed. There was an association between positive skin test results with YFV and the severity of the reaction (OR:7.64; 95%CI:1.61-36.32; p =0,011). Only the presence of sIgE to ovomucoid was associated with clinical symptoms (p =0,025). Thirty patients underwent the YFV desensitization protocol. Conclusion There is a relationship between the positivity of the egg's components and the severity of the clinical reaction. Furthermore, the relationship between the positivity of the tests with the YFV and egg's components may show a tendency to look at ovomucoid and conalbumin, but it is not a certainty. Therefore, further studies are needed to confirm these associations, and for now, the authors still recommend using the vaccine for testing when necessary.

Abstract Objective Allergic sensitization is one of the key components for the development of allergies. Polysensitization seems to be related to the persistence and severity of allergic diseases. Furthermore, allergic sensitization has a predictive role in the development of allergies. The aim of this study was to characterize the pattern of sensitization of atopic patients treated at different pediatric allergy referral centers in Brazil. Methods A nation-wide transversal multicenter study collected data on patients attended in Brazil. Peripheral blood samples were collected to determine the serum levels of allergen-specific IgE. If allergen-specific IgE was higher than 0.1 kUA/L, the following specific components were quantified. Results A total of 470 individuals were enrolled in the study. Mite sensitization was the most frequent kind in all participants. A high frequency of sensitization to furry animals and grasses featured in the respiratory allergies. Regarding components, there was a predominance of sensitization to Der p 1 and Der p 2. It has been verified that having a food allergy, atopic dermatitis, or multimorbidity are risk factors for the development of more severe allergic disease. Conclusion Studies on the pattern of allergic sensitization to a specific population offer tools for the more effectual prevention, diagnosis, and treatment of allergic diseases. Sensitization to dust mites house was the most prevalent in the evaluated sample. High rates of sensitization to furry animals also stand out. Patients with food allergy, atopic dermatitis, or multimorbidity appear to be at greater risk for developing more severe allergic diseases.

Fundamentos: Os testes cutâneos de hipersensibilidade imediata (TCHI) são ferramentas importante na avaliação da sensibilização alérgica. Vários fatores podem interferir no seu resultado. O índice cutâneo (IC, relação entre o diâmetro da pápula induzida pelo alergénio e o da histamina correspondente) tem sido utilizado para melhorar o poder diagnóstico do TCHI, sobretudo em crianças de baixa idade. Objetivo: Avaliar o valor do IC na identificação de sensibilização alérgica em doentes seguidos em serviço pediátrico especializado. Material e métodos: Os TCHI de 1662 doentes, atendidos entre 2009 e 2014, foram realizados com alérgenos inalantes, além de controlo negativo (solução salina) e controlo positivo (histamina, 1mg/mL)(IPI‑ASAC ® Brasil). Foram anotados os diâmetros médios das pápulas e os doentes agrupados por faixa etária. Resultados: Todos apresentaram pápula de histamina com diâmetro superior a 3 mm. A reatividade cutânea à histamina aumentou significativamente com o progredir da idade. D.pteronyssinus e B. tropicalis foram os principais aeroalergénios identificados. O estudo do IC permitiu estabelecer valores de corte no diagnóstico de sensibilização alérgica, sendo 0,6 para os ácaros. Entretanto, o emprego isolado do IC como critério diagnóstico de sensibilização reduziu a frequência de doentes sensibilizados. Conclusões: O IC pode ser utilizado como critério adicional para o diagnóstico de sensibilização alérgica nos doentes que apesar de terem manifestado reatividade cutânea baixa tiverem índice cutâneo acima de 0,6 para D. pteronyssinus ou B. tropicalis.

Rationale: Skin prick test (SPT) is an important tool in the evaluation of allergic sensitization and can be influenced by several factors. Skin index (ratio of allergen‑induced wheal diameter and corresponding histamine diameter; SI) have been used to improve the diagnostic power of SPT, especially in young children. Objective: To evaluate the SI in identifying allergic sensitization in patients followed at a specialized pediatric clinic. Material and methods: SPT of 1662 patients performed, between 2009 and 2014, to inhalant allergens, negative control (saline) and positive control (histamine, 1mg/mL) (IPI‑ASAC ® Brazil) were analyzed. Mean wheal diameters of allergens, histamine and negative control were recorded, according to different ages. All patients had a histamine positive SPT (wheal diameter equal or higher than 3 mm). Results: Skin reactivity to histamine increased significantly with increasing age. D. pteronyssinus and B. tropicalis were the predominant inhalant allergens identified. SI cut‑off points for the diagnosis of allergic sensitization were 0.6 for dust mites. However, when applying SI alone as the single diagnostic criteria for sensitization, we observe a reduction in the prevalence of sensitized patients. Conclusions: SI should be used in addition to SPT for the diagnosis of allergic sensitization in those patients who, despite of having low skin reactivity, had SI above 0.6 for D. pteronyssinus or B. tropicalis.