Urticaria papular y sus agentes causales en Colombia / Papular urticaria: A review of causal agents in Colombia

Resumen La urticaria papular es una enfermedad alérgica causada por la picadura de insectos, la cual predomina en el trópico. El objetivo de esta revisión fue profundizar en sus aspectos epidemiológicos e inmunológicos, particularmente con base en datos publicados en Latinoamérica. Se hizo una revisión no sistemática mediante la búsqueda electrónica de artículos sobre la epidemiología de la urticaria papular, las características entomológicas de los agentes causales y los mecanismos inmunológicos asociados. Según los diversos reportes de centros médicos de Latinoamérica la urticaria papular es frecuente; el único estudio de prevalencia publicado indica que afecta a una cuarta parte de los niños escolares de Bogotá. Hay información sobre la relación causal entre la exposición domiciliaria a la pulga, la pobreza y la urticaria papular en Bogotá, una ciudad representativa de las altitudes andinas. No hay estudios que indaguen directamente sobre los insectos causales en zonas cálidas, aunque se sospecha clínicamente de los mosquitos Aedes aegypti y Culex quinquefasciatus. En cuanto a su patogenia, se destaca la participación de mecanismos celulares que involucran las células colaboradoras Th2, lo cual explica que sea una condición de hipersensibilidad retardada. El papel de la inmunoglobulina E (IgE) en la urticaria papular no está tan claro. Se desconocen los antígenos derivados de los insectos que causan la enfermedad, aunque se plantea que existen moléculas comunes de reacción cruzada entre los insectos, tales como el alérgeno Cte f 2 en la pulga, y sus homólogos en los mosquitos. La urticaria papular es una condición frecuente en Latinoamérica que debe investigarse en profundidad. La caracterización inmunológica de los componentes moleculares que causan esta condición puede resolver interrogantes sobre su etiología y su patogenia.

Abstract Papular urticaria is a chronic allergic reaction induced by insect bites, which is common in the tropics. The objective of this review was to deepen on epidemiological and immunological aspects of this disease, focused on data published in Latin American countries. We conducted a non-systematic review of the literature through electronic search on the epidemiology of papular urticaria, the entomological characteristics of the causative agents and associated immunological mechanisms. Several reports from medical centers suggest that papular urticaria is common in Latin America. Only one epidemiological survey designed to estimate prevalence of papular urticaria has been published, reporting that about a quarter of children under six years of age is affected by this condition in Bogotá. There is evidence on the causal relationship among exposure to indoor fleas, poverty and papular urticaria in Bogotá, a representative city of the Andean altitudes. Information about causal insects in tropical warmer areas is scarce, although from clinical reports Aedes aegypti and Culex quienquefasciatus appear to be the most common. Th2 cellular-mediated mechanisms are involved in its pathogenesis, which explains its delayed hypersensitivity. The role of immunoglobulin E is not clear in this disease. Insect-derived antigens directly involved in papular urticaria etiology are unknown. However, it is possible that common molecules among causal insects mediate cross-reactive reactions, such as Cte f 2 allergen, found in cat fleas, and its counterparts in mosquitoes. Papular urticaria is a frequent disease in Latin America that should be further investigated. Immunological characterization of the molecular components that cause this condition may solve questions about its pathogenesis.

Expresión de IL-10, IL-4 e IFN- γ en lesiones activas de piel en niños con urticaria papular por picadura de pulga / Expression of IL-10, IL-4 and IFN-γ in active skin lesions of children with papular urticaria

Introducción. La urticaria papular por picadura de pulga se conoce como una enfermedad alérgica. Sin embargo, las investigaciones no muestran una clara relación con las enfermedades alérgicas. Objetivo. Estudiar la expresión de IL-10, IL-4 e IFN-γ, como marcadores de la respuesta efectora de células T en lesiones de piel de pacientes con urticaria papular por picadura de pulga. Materiales y métodos. Se incluyeron 14 biopsias de lesiones de piel de niños con diagnóstico de urticaria papular por picadura de pulga y 5 biopsias de piel sana obtenidas de niños sometidos a cirugía por enfermedades no inflamatorias. Todas las muestras se obtuvieron de niños menores de 12 años. Se extrajo ARN con trizol y se cuantificaron los niveles de expresión de las citocinas con la técnica de reacción en cadena de la polimerasa en tiempo real. Resultados. En los pacientes con urticaria papular por picadura de pulga, se encontró amplia diversidad en los niveles de expresión de IFN-γ e IL-10, y valores bajos constantes para IL-4. Se observaron tres perfiles que no corresponden a un patrón común en los pacientes. Las muestras obtenidas de tejidos sanos no presentaron expresión de las citocinas. Conclusiones. Los datos corresponden a la primera descripción de citocinas que median la respuesta inmunitaria en el sitio de la lesión cutánea en niños con con urticaria papular por picadura de pulga, lo cual indica que la respuesta local es mixta ya que no se encuentra predominio de un fenotipo específico en ninguno de los pacientes.

Introduction: Papular urticaria caused by the bites of fleas traditionally has been defined as a chronic allergic disease. However, currently no clear relationship has been described between this pathology and common allergic diseases. Objective: The expression of IL-10, IL-4 and IFN-γ as markers of effector T cell responses was examined in skin lesions of patients with papular urticaria by flea bite. Materials and methods: Fourteen skin lesion biopsies were sampled from children with a clinical diagnosis of papular urticaria by flea bite and were compared with 5 healthy skin biopsies of children with no history of the disease. All children were under 12 years old. RNA was extracted with trizol and the expression levels of cytokines were analyzed by real time PCR technique. Results: A wide range in the expression levels of IFN-γ and IL-10 was noted as well as constant low values of IL-4. Three distinct profiles were observed, but which did not correspond to a recognizable pattern among the patients. The samples obtained from healthy tissues showed no expression of any of the cytokines. Conclusions: This is the first characterization of cytokines that mediate the immune response at the site of the skin lesion in children with papular urticaria by flea bite. The data indicated that the local response was mixed and that a single phenotype is not predominant among the patients.

Specific immunotherapy using Hymenoptera venom: systematic review / Imunoterapia específica com venenos de Hymenoptera: revisão sistemática

CONTEXT AND OBJECTIVE: The only effective treatment for patients who have severe reactions after Hymenoptera stings is venom immunotherapy. The aim of this study was to review the literature to assess the effects of venom immunotherapy among patients presenting severe reactions after Hymenoptera stings. DESIGN AND SETTING: Randomized controlled trials in the worldwide literature were reviewed. The manuscript was produced in the Discipline of Allergy and Clinical Immunology, Universidade de São Paulo (USP). METHODS: Randomized controlled trials involving venom immunotherapy versus placebo or only patient follow-up were evaluated. The risk of systemic reactions after specific immunotherapy was evaluated by calculating odds ratios (OR) and their 95 percent confidence intervals. RESULTS: 2,273 abstracts were identified by the keywords search. Only four studies were included in this review. The chi-square test for heterogeneity showed that two studies were homogeneous and could be included in a meta-analysis. By combining the two studies, the odds ratio became significant: 0.29 (0.10-0.87). However, analysis on the severity of the reactions after immunotherapy showed that the benefits may not be so significant because the reactions were mostly similar to or milder than the original reaction. CONCLUSIONS: Specific immunotherapy should be recommended for adults and children with moderate to severe reactions, but there is no need to prescribe it for children with skin reactions alone, especially if the exposure is very sporadic. On the other hand, the risk-benefit relation should always be assessed in each case.

CONTEXTO E OBJETIVO: O único tratamento eficaz para pacientes que têm reações graves após ferroada de Hymenoptera é a imunoterapia com veneno. O objetivo deste estudo foi rever a literatura para avaliar os efeitos da imunoterapia com veneno em pacientes com reações graves após ferroada de Hymenoptera. TIPO DE ESTUDO E LOCAL: Foram revisados na literatura mundial ensaios clínicos controlados e aleatórios. O manuscrito foi realizado na Disciplina de Alergia e Imunologia Clínica, Universidade de São Paulo (USP). MÉTODOS: Ensaios clínicos controlados e aleatórios envolvendo imunoterapia com veneno de Hymenoptera versus placebo ou apenas acompanhamento dos pacientes foram avaliados. Realizada imunoterapia específica, o risco de reações sistêmicas foi avaliado através de cálculo do "odds ratio" e intervalo de confiança de 95 por cento. RESULTADOS: 2.273 resumos foram identificados na busca pelas palavras chave. Apenas quatro estudos foram incluídos nesta revisão. O teste qui-quadrado de heterogeneidade mostrou que dois estudos foram homogêneos e puderam ser incluídos na metanálise. Ao combinar os dois estudos, o "odds ratio" passou a ser significativo: 0.29 (0.10-0.87). Entretanto, ao analisar a gravidade das reações ocorridas após a imunoterapia, observou-se que os benefícios podem não ser tão relevantes, pois as reações foram, na grande maioria, ou mais leves ou semelhantes à reação original. CONCLUSÕES: A imunoterapia específica deve ser recomendada para adultos e crianças com reações moderadas a graves, porém não há necessidade de prescrevê-la para as crianças apenas com reações cutâneas, especialmente se a exposição é muito esporádica. No outro lado, a relação risco-benefício deve ser sempre avaliada em cada caso.

Inmunoterapia con veneno de himenópteros: presentación de diez casos clínicos / Immunotherapy against hymenoptera venom: Report of ten patients

Background: Immunotherapy can be used to treat allergic reactions to insect stings, specially bees and wasps. Aim: To report the experience with immunotherapy with aqueous extracts of hymenoptera venoms (bees and wasps). Material and methods: Ten patients aged 6 to 58 years were treated in an allergy center of a University Clinical Hospital. The medical indication for this treatment was, in all patients, anaphylactic reactions after hymenoptera stings. Immunotherapy was carried out using standardized vaccines (Aqueous extracts Venomvac LETI, Spain), applied in a traditional protocol, with subcutaneous injections. This protocol had two phases: a buildup phase (between weeks 1 and 13) and a monthly maintenance phase, from the 13th week. The monthly maintenance dose was 100 fig of hymenoptera specific venom extract. Results: Six patients had adverse reactions of different severity, during the treatment protocols and all had a good response to immediate therapeutic measures. After these events, they followed the protocol without problems. Two patients, treated with bee vaccines, suffered an accidental bee sting during the maintenance phase and they developed only local reactions. Conclusions: The lack of adverse reactions to bee stings in these two patients indicates the acquisition of clinical tolerance.

Cutaneous allergic vasculitis due to Solenopsis geminata (Hymenoptera: Formicidae) envenomation in Indonesia.

Severe cutaneous allergic vasculitis in a 60 year-old Caucasian male following the bite of the tropical fire ant, Solenopsis geminata (F.) is reported. Over the course of 8 weeks, the pathology progressed from an extensive red papular urticaria to vasculitis with peri-vascular inflammation and ulceration of the skin on the feet, ankles and lower limbs. Many of the affected areas of the skin eventually became covered with black eschar associated with further tissue breakdown and ulcer formation. After debridement, compression dressings, antimicrobial ointment and corticosteroids, complete healing eventually took place with only residual scarring. An awareness of the severe dermatologic reactions caused by a bite of S. geminata, albeit rare, is clinically important. Recognizing the characteristic skin lesions caused by the bite of S. geminata, treated with prompt administration of appropriate chemotherapy will speed recuperation of the patient and reduce possible secondary complications.

Características clínicas das reações por venenos de Hymenoptera e valor diagnóstico da determinação de IgE sérica específica nas alergias provocadas por estes insetos / Clinical characteristics of Hymenoptera venom reactions and the value of specific serum IgE determination in the diagnosis of these insect allergies

A ordem Hymenoptera é constituída pelas abelhas, vespas e formigas. Alergias aos venenos desses insetos podem ocasionar reações graves, muitas vezes fatais. O Brasil possui poucos dados epidemiológicos sobre alergia aos himenópteros e há poucos estudos que avaliem as características da determinação de IgE sérica específica e o seu papel no diagnóstico da alergia a estes insetos. Este trabalho tem como objetivo estudar os pacientes com alergia a himenópteros, em relação a parâmetros clínicos e testar o valor diagnóstico do método utilizado para a determinação sérica de IgE específica, de acordo com os parâmetros de sensibilidade, especificidade, valores preditivo positivo e negativo./The Hymenoptera order is constituted by bees, wasps and ants. The insect venoms allergies could provoke severe reactions, many times fatal. Brazil has few epidemiologic data about Hymenoptera allergy and there are few studies about specific serum IgE determination characteristics and its role in these insect allergies diagnosis. The aims of the present study are to analyze the patients with Hymenoptera allergy history based on clinical parameters and analyze the diagnostic value of the method used in specific serum IgE determination considering sensitivity, specificity, positive and negative predictive values...

Reaçäo anafilactóide por veneno de abelha em pacientes com mastocitose / Anaphylactoid reaction to the bee venom in a patient with mastocitosis

Objetivo: Apresentar um caso de reaçao anafilactoide por veneno de abelha em um paciente com Mastocitose cutânea. Método: Avaliaçao clínica, exames laboratoriais e pesquisa de IgE específica ao veneno de abelha pela técnica do RAST (radioallergosorbent test) e biópsia cutânea. Resultados: A biópsia confirmou o diagnóstico de Mastocitose cutânea e a IgE especifica ao veneno de abelha foi negativa. Conclusoes: Manifestaçoes sistêmicas por venenos de himenópteros (abelhas, vespas e formigas) com testes cutâneos e RAST negativos nao sao incomuns. A Mastocitose é caracterizada pela proliferaçao anormal de mastócitos e pela liberaçao elevada de mediadores químicos. Cinicamente pode ser restrita à pele ou pode envolver diversos órgaos como a medula óssea, baço, fígado, linfonodos, trato gastrointestinal e sistema esquelético. Neste artigo apresentamos um caso de reaçao anafilactoide por veneno de abelha em um paciente com Mastocitose cutânea.

Picadura por abejas africanizadas / Africanzed bee venom stings

Las abejas africanizadas ("abejas asesinas") se han caracterizado por su agresividad, que da origen a ataques masivos durante los cuales inyectan a su victima una cantidad importante de veneno. El veneno inyectado contiene sustancias tóxicas capaces de producir, entre otros síndromes clínicos, muerte por insuficiencia renal aguda. En este trabajo se hace revisión de la literatura, asi como un análisis de la presentación clínica y el manejo

Anafilaxia / Anaphilaxia

La anafilaxia sistémica resulta de la liberación de mediadores de una variedad de células inflamatorias. La mayoría de las reacciones son debidas a medicamentos, piquetes de insectos, alimentos, medios de radiocontraste, vacunas, sueros heterólogos, productos sanguíneos, hiposensibilización, etc. Es relativamente fácil su diagnóstico en la mayoría de los casos, con un cuadro clínico que puede ir desde simples lesiones en piel como urticaria hasta el compromiso cardiovascular y respiratorio que comprometa la vida. Como en todos los casos el manejo será encaminado a mantener las vías aéreas permeables y la homeostasis cardiovascular. La adrenalina constituye la primera línea terapéutica por sus acciones adrenérgicas, acompañadas con soluciones cristaloides o coloides para restaurar el volumen vascular, así como también con antihistamínicos y esteroides (para la fase tardía) de acuerdo a la intensidad del cuadro clínico. El manejo óptimo a largo plazo del paciente incluye la identificación del agente causal, la educación del paciente y de sus familiares para el empleo de la adrenalina en situaciones de exposición accidental que puedan desencadenar la muerte