Anafilaxia à lapa: um caso clínico raro / Limpet anaphylaxis: a rare case

A lapa (Patella vulgata) é um molusco frequentemente encontrado em regiões costeiras com clima quente. A alergia alimentar à lapa é muito rara, com poucos casos descritos na literatura. Os autores descrevem um caso de anafilaxia à lapa, com evidência de reação de hipersensibilidade do tipo I, através de IgE específica positiva à lapa, tanto com métodos in vivo, como in vitro.

Limpet (Patella vulgata) is a mollusk mainly found in warm coastal regions. Limpet allergy is considered rare, and few cases can be found in the literature. We describe a clinical case of limpet anaphylaxis, including in vitro and in vivo evidence of IgE mechanism involvement.

Guia prático de urticária aguda / Practical guide to acute urticaria

A urticária aguda é uma causa frequente de consulta com alergistas, caracterizada por urticas e/ou angioedema. Embora autolimitada e benigna, pode causar desconforto significativo e raramente representar uma doença sistêmica grave ou reação alérgica com risco de vida. Nesta revisão, elaborada pelo Departamento Científico de Urticária da Associação Brasileira de Alergia e Imunologia, foram abordadas as principais questões referentes ao tema para auxiliar o médico especialista e generalista.

Acute urticaria is a frequent cause of consultations with allergists, being characterized by wheals and/or angioedema. Although self-limited and benign, it may cause significant discomfort and uncommonly represent a serious systemic disease or life-threatening allergic reaction. In this review prepared by the Urticaria Scientific Department of the Brazilian Association of Allergy and Immunology, the main questions about this topic are addressed to help specialists and general practitioners.

Identification of arginine kinase as an allergen of brown crab, Callinectes bellicosus, and in silico analysis of IgE-binding epitopes.

In recent years there has been an increase in the prevalence of allergic reactions to contact with/or consumption of crustaceans by immune responses mediated by IgE antibodies. Arginine kinase (AK) is considered one of the main allergens present in marine invertebrates. Currently, the allergenic potential of the brown crab (Callinectes bellicosus), which is a crustacean of great economic importance, has not been studied. Therefore, the aim of this work was to identify C. bellicosus AK as an allergen and to predict IgE-binding epitopes through immunobioinformatic analysis. AK was purified by precipitation with ammonium sulfate and ion- exchange chromatography. AK allergenicity was evaluated by IgE reactivity against sera from crustacean-allergic and non-allergic patients in both native and denaturing conditions. Additionally, a homology model was built based on the deduced amino acid sequence. A single band (~40 kDa) was found in SDS-PAGE, which was identified as an AK by mass spectrometry. AK showed immunoreactivity against crab-allergenic sera in both native and denaturing conditions with 70% and 80% positive reactions, respectively. Additionally, a 1073 bp ORF was obtained which codes for a deduced sequence of 357 amino acids corresponding to AK with > 90% identity with other AKs. Structural homology model of AK showed two main domains with conserved / folding of phospho-guanidine kinases. BediPred and Discotope were used for epitope prediction analysis, which suggests eight possible linear epitopes and seven conformational epitopes, respectively; and shows to be similar to other crustaceans AKs. C. bellicosus AK was identified as an allergenic protein by IgE reactivity and immunobioinformatic analysis indicates that both linear and conformational epitopes could be located in the surface of C. bellicosus AK structure.

Correlação entre o autodiagnóstico de alergia alimentar e a presença de IgE específica / Correlation between self-diagnosis of food allergy and presence of specific IgE

Introdução: Nos últimos anos a prevalência de alergia alimentar tem aumentado, contudo, o número de autodiagnósticos errados, também. Essa superestimação dos diagnósticos, frequentemente, culmina em dietas restritivas desnecessárias que podem, muitas vezes, ocasionar mais danos do que benefícios para a saúde. Objetivo: Avaliar a relação entre o autodiagnóstico de alergia alimentar e a presença de IgE específica para o referido alimento. Método: Trata-se de um estudo transversal e observacional que avaliou 100 pacientes que aceitaram participar da pesquisa, com idade entre 18 e 75 anos, por meio de um questionário próprio para investigação do autodiagnóstico de doenças alérgicas e um teste cutâneo de leitura imediata ou prick test para detecção de IgE específica para alimentos que podem induzir a uma reação alérgica. Resultados: Foram aplicados e analisados 100 questionários em voluntários na faixa etária de 18 a 75 anos. Destes, 35 pacientes afirmaram ter alergia alimentar durante a aplicação do questionário. Apenas 10 tiveram resultado positivo ao prick test. A maioria dos resultados positivos no prick test estavam associados ao camarão, ao amendoim e ao caranguejo. Conclusão: O presente estudo evidenciou uma importante superestimação do número de autodiagnósticos de alergias alimentares, sendo o número de pacientes que se autodeclararam alérgicos a alimentos consideravelmente maior do que os resultados positivos no prick test. Constata-se que é necessário mais estudos que possuam em sua metodologia informações pré e pós-testes diagnósticos de alergia alimentar, para uma correta avaliação da proporção de casos.

Introduction: In recent years, the prevalence of food allergy has increased, as well as the number of incorrect self-diagnoses. This overestimation of diagnoses often culminates in unnecessary restrictive diets that may cause more harm than benefits to health. Objective: To evaluate the relationship between self-diagnosis of food allergy and the presence of specific IgE for that food. Method: This is a cross-sectional and observational study that evaluated 100 patients who agreed to participate in the research, aged between 18 and 75 years. A questionnaire was used to investigate the self-diagnosis of allergic diseases, and a skin prick test was used to detect food-specific IgE that may induce an allergic reaction. Results: One hundred questionnaires were administered and analyzed in volunteers aged from 18 to 75 years. Of these, 35 patients claimed to have food allergy during the administration of the questionnaire. Only 10 tested positive on the prick test. Most positive prick test results were associated with shrimp, peanut, and crab. Conclusion: The present study showed an important overestimation of the number of self-diagnosed food allergies, as the number of patients who self-reported being allergic to food was considerably greater than that of positive prick test results. More studies that have in their methods pre- and post-diagnostic information from food allergy tests are needed for a correct assessment of the proportion of cases.

Prevalence of Peanut, Tree Nut, Sesame, and Seafood Allergy in Mexican Adults.

OBJECTIVE: To identify the prevalence of perceived and probable allergic reactions to peanuts, tree nuts, sesame seed, or seafood and its association with the personal history of allergic disease. METHODS: A cross-sectional study was performed in four cities of the metropolitan area of Guadalajara, located in western Mexico. Through sampling by gender and age, 1,126 subjects were included. Using a structured questionnaire, we investigated: (i) history of atopic disease, (ii) perception of allergic reaction after food intake, and (iii) probable allergic reaction to peanuts, tree nuts, sesame, or seafood. Prevalence and 95% confidence intervals were calculated. A multivariate analysis of factors associated to perceived and probable allergic reactions to food was performed by logistic regression. RESULTS: Men were 49.8%; mean age was 28.1 years; personal history of atopic disease included: allergic rhinitis (6.9%), asthma (6.8%), and atopic dermatitis (3.8%). Prevalence of perceived and probable food allergy was, respectively: pecan 0.4 and 0.3%; peanut 0.6 and 0.6%; sesame 0.1 and 0.1%; shellfish 4.2 and 4.0% (mainly shrimp); mollusk 0.8 and 0.7%; fish 1.4 and 1.2%. Asthma was significantly associated with perceived and probable allergy to pecans, peanuts, fish, or seafood. Atopic dermatitis was associated with perceived and probable allergic reaction to sea snail, seafood, shellfish, or mollusks. Finally, allergic rhinitis was associated with allergy to shrimp and crustaceans. CONCLUSIONS: This study shows that the prevalence of peanut, tree nut, sesame seed, and seafood allergy in this Mexican population is similar to that reported in developed countries.