Classification of contact allergens according to potency: proposals.

It is clear that contact allergens vary substantially with regard to the relative potency with which they are able to induce skin sensitisation. Considerations of potency will in the future become a significant factor in the classification of skin sensitising chemicals. It is therefore appropriate to establish what is known of potency and thresholds in the induction of skin sensitisation and the elicitation of allergic contact dermatitis, and to identify approaches that might be available for assessment of relative potency for the purposes of categorising chemical allergens. This paper was prepared by an ECETOC (European Centre for Ecotoxicology and Toxicology) Task Force that had the objective of recommending approaches for the measurement of potency and definition of thresholds for both the induction and elicitation of contact sensitisation. The deliberations recorded here build upon recommendations made previously by an ECETOC Task Force that considered the conduct of standard skin sensitisation test methods for the purposes of hazard identification and risk assessment (ECETOC, Monograph No. 29, Brussels, 2000). The emphasis in this present paper is also on standard and accepted methods for the assessment of skin sensitisation, and for which OECD guidelines are available: the local lymph node assay (LLNA), the guinea pig maximisation test and the occluded patch test of Buehler. For various reasons, discussed in detail herein, attention focused primarily upon consideration of categorisation of chemical allergens and the identification of thresholds with respect to the induction of skin sensitisation, rather than the elicitation of allergic contact dermatitis. It is concluded that although the LLNA is the method of choice for the determination of skin sensitisation potency for the purposes of categorisation, if data are already available from appropriate guinea pig tests then their judicious interpretation may provide information of value in determinations of potency and categorisation. Included here are detailed and specific recommendations for how best the results of the three test methods considered can be used for the categorisation of chemical allergens as a function of skin sensitisation potency.

Atopic dermatitis in adults: a diagnostic challenge

Atopic dermatitis (AD) has a prevalence of 1%-3% in adults. Adult-onset AD has only been defined recently, and lack of familiarity with this condition and confusion regarding the appropriate terminology persist. AD may first appear in childhood or de novo in adults and is characterized by pronounced clinical heterogeneity. The disease often deviates from the classic pattern of flexural dermatitis, and there are forms of presentation that are specific to adults, such as head-and-neck dermatitis, chronic eczema of the hands, multiple areas of lichenification, or prurigo lesions. Although diagnosis is clinical, adult-onset AD frequently does not fit the traditional diagnostic criteria for the disease, which were developed for children. Thus, AD is often a diagnosis of exclusion, especially in de novo cases. Additional diagnostic tests, such as the patch test, prick test, skin biopsy, or blood test, are usually necessary to rule out other diseases or other types of eczema appearing concomitantly with AD. This article presents an update of the different forms of clinical presentation for AD in adults along with a proposed diagnostic approach, as new treatments will appear in the near future and many patients will not be able to benefit from them unless they are properly diagnosed (AU)

La dermatitis atópica (DA) en el adulto tiene una prevalencia del 1-3%. Es una entidad de reciente acuñamiento, que no todo el mundo conoce y sobre la que existe una gran confusión terminológica. Puede iniciarse en la infancia o presentarse de «novo» en el adulto. Presenta una gran heterogeneidad clínica y con frecuencia no sigue el patrón clásico de dermatitis flexural. Además, existen formas de presentación más propias de adulto como son la dermatitis de la cabeza y el cuello, eczema crónico de manos, áreas de liquenificación múltiple o lesiones de prurigo. Aunque su diagnóstico es clínico, muchas veces la DA del adulto no cumple los criterios diagnósticos «clásicos» de DA, pues están pensados para niños. Por eso, suele ser un diagnóstico de exclusión, sobre todo los casos de «novo». Suele precisar de la realización de pruebas diagnósticas para descartar otras enfermedades distintas u otro tipo de eczema sobreañadido a la DA. Las pruebas diagnósticas que pueden resultar útiles para ello son: pruebas epicutáneas, prick test, biopsia cutánea y una analítica sanguínea. Realizamos una actualización de las distintas formas de presentación clínica de la DA del adulto y establecemos unas pautas para llegar a su diagnóstico, pues en un futuro inmediato, con la aparición de nuevos tratamientos, muchos de estos pacientes no podrán beneficiarse de los mismos por no estar adecuadamente diagnosticados (AU)

Impact of glutathione on the allergenicity of the peach lipid transfer protein pru p 3

Background and Objective: The allergenic potential of proteins can be altered under various physicochemical conditions. Glutathione (GSH) is a reducing agent that is used as an antioxidant in food products. We aimed to characterize the natural folding of peach proteins and test the allergenicity of reduced and natural Pru p 3, the major peach allergen. Methods: Pru p 3 was purified from peach, and its conformation was analyzed by means of circular dichroism. Using a thiol fluorescent probe, reduced proteins were detected in fresh peach. GSH-reduced Pru p 3 was tested in vitro for T-cell proliferation and in vivo using skin prick testing. Results: GSH-reduced Pru p 3 produced variable skin prick reactions in peach-allergic patients. The proliferative response of peripheral blood mononuclear cells from allergic patients to reduced Pru p 3 tended to be less intense, whereas secretion of the cytokines IFN-, IL-5, and IL-10 was comparable. In a pool of sera from peach-allergic patients, reduction hardly impaired IgE-binding. Moreover, the stability of reduced Pru p 3 to gastrointestinal digestion was similar to that of the natural form. Conclusions: GSH can at least transiently reduce Pru p 3. We found that the effect of reduction on the allergenicity of Pru p 3 varied. Therefore, as an additive, GSH does not seem to eliminate the risk of reactions for peach-allergic patients (AU)

Antecedentes: El potencial alergénico de las proteínas puede alterarse mediante modificaciones fisicoquímicas. El glutatión (GSH) es un agente reductor utilizado como antioxidante en productos alimentarios. Objetivo: Este estudio pretende caracterizar el plegamiento natural de las proteínas de melocotón y cuantificar la alergenicidad del alérgeno mayor del melocotón, Pru p 3, natural y reducido. Métodos: Para ello, se purificó Pru p 3 y se analizó su conformación mediante dicroismo circular (DC). Mediante el análisis con tiol fluorescente, se detectaron las proteínas reducidas en melocotones frescos. Pru p 3 reducido por GSH fue analizado mediante un ensayo in vitro de proliferación de células T e in vivo mediante prueba cutánea. Resultados: Pru p 3 reducido produjo reacciones variables en las pruebas cutáneas de los pacientes alérgicos a melocotón; sin embargo, su estabilidad a la digestión gastrointestinal fue similar a la de la forma natural. La respuesta proliferativa de las células mononucleares de los pacientes alérgicos frente a Pru p 3 reducido mostró una tendencia a ser inferior, mientras que la secreción de citocinas IFN, IL5 e IL10 fue similar a la producida con la forma natural. La reducción alteró la unión de la IgE a Pru p 3 en un pool de sueros de pacientes alérgicos a melocotón. Conclusión: En conclusión, el glutatión es capaz de reducir Pru p 3, al menos de forma transitoria. En nuestro estudio, la reducción no afectó a la alergenicidad de Pru p 3, de forma que dicho aditivo no parece resolver el riesgo de alergia en pacientes alérgicos a melocotón (AU)

Alérgenos en la dermatitis de contacto alérgica de origen laboral / Allergens in occupational allergic contact dermatitis

Introducción: Las dermatosis profesionales tienen una alta incidencia, lo que conlleva considerables consecuencias médicas y laborales. Objetivos: Describir las características de la población afectada por dermatitis de contacto alérgica de origen laboral y los alérgenos responsables. Material y Métodos: Durante cinco años se incluyó a todos los pacientes diagnosticados de Dermatitis de Contacto Alérgica en una consulta de Dermatología en un hospital de referencia, con positividad a al menos un alérgeno presente en su puesto de trabajo. Resultados: En sector de cosmética el 93,7% fue causada por acrilatos, en peluquería un 72,7% fue causada por PPDA, en alimentación un 63,3% de los alérgenos fueron productos alimentarios, en construcción el 60% fueron causadas por cemento y en industria PPDA causó un 30%. Las manos fueron la principal área corporal afectada en todos los grupos laborales. Conclusión: parece recomendable mejorar la coordinación entre los facultativos de Medicina del Trabajo y de atención primaria con los facultativos dermatólogos, estableciéndose protocolos de actuación conjuntos que permitan disponer de un diagnóstico definitivo en el menor tiempo posible (AU)

Introduction: The occupational dermatosis have a high incidence, leading to considerable medical and occupational consequences. Objectives: Describe the characteristics of the population affected by allergic contact dermatitis of labor origin and allergens responsible. Methods: During 5 years, all Allergic Contact Dermatitis were includedat the time of diagnosis, on a Dermatology outpatient department in a tertiary hospital, with positivity for at least 1 allergen present in their workplace. Results: In Cosmetics a 93.7% was caused by acrylates, in Hairdressing a 72.7% was caused by PPDA in Food Workers 63.3% of allergens were food products, in Construction a 60% were caused by cement and in Industry PPDA caused a 30%. The hands were the main body area affected in all labor groups. Conclusions: it seems to need an improvement about the communication and protocols between Occupational Medicine, Family Medicine and Dermatology to short the time of the diagnosis of these occupational diseases (AU)

Are skin prick tests really safe? A case of anaphylaxis caused by skin prick testing with inhalant allergens

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[Skin tests in allergy]. / Pruebas cutáneas en alergia.

Allergen skin testing is one of the preferred in vivo methods for assessing the presence of specific IgE antibodies against an allergen. This article review the clinical applications, techniques, reagents, evaluation, and safety of skin testing to help the allergologist to its better clinical use.

Allergenicity testing of supermethrin, phenoxyacetic acid and DNCB using in vivo and in vitro modifications of the local lymph node assays, maximization and epicutaneous testing.

The purpose of this study was to compare two methods of testing for allergenicity: in vivo and in vitro modifications of local lymph node assays (LLNA) in mice and the maximization and epicutaneous skin tests in guinea pigs as per the Organization for Economic Cooperation and Development (1981). Two pesticides-the synthetic pyrethroid insecticide supermethrin (SM) and the herbicide phenoxyacetic acid (PAA)-were evaluated using this testing battery. 1-Chloro-2,4-dinitrobenzene (DNCB) was selected as a reference allergen for the local lymph node assay. In vitro modification of LLNA proliferative response per standard cell count in lymphocyte cultures derived from treated Balb/c mice did not differ from control mice. Results of the in vivo modification showed that treatment with 50% PAA and 50% SM resulted in a lower proliferation response of lymphocytes in lymph nodes compared with control animals. The vigour of the proliferative response varied more in in vivo modification of LLNA. Stimulation indices were <3, so PAA and SM did not indicate classification as allergens. Lymphocyte proliferation in 1% DNCB-activated lymph nodes was approximately fivefold higher than in those derived from control mice. Proliferation response in vitro calculated as stimulation index was higher in DNCB-treated mice than those observed in vivo, but differences were not dramatic. Auricular lymph node weight and cellularity in mice treated with PAA and SM were similar to controls. The DNCB stimulation index for lymph node cellularity was 5.5. Lymph node weight was three times higher in comparison with controls. In the maximization test in guinea pigs SM and PAA acid resulted in 40% and 50% of animals demonstrating sensitization, respectively. Epicutaneous administration resulted in weaker reaction. Both SM and PAA are mildly strong sensitizers by this battery.

Some aspects of immunity in leprosy and their importance in epidemiology, pathogenesis and classification of forms of the disease: based on 1529 lepromin tested cases

The author describes the technique employed in the preparation of lepromin, the types of reaction found, the criterion of reading, etc. He considers as positive reactions those with more than 5 mm diameter in the 30th day of reading. Reactions were studied in 1529 individuals, both lepers and healthy, with or no contact with leprosy; and the results are correlated with age, sex, race, nationality, degree of bacillary elimination, types of diseases, debility of the body through various diseases, speed of sedimentation of the red cells, lepra reaction, (present or prior to the test). Analyzing his results, together with the works of various authors, about lepromin, in endemic and non-endemic zones, and comparing the data with those of general pathology, in particular with tuberculosis, he arrives at the following conclusions: Epidemiology - Leprosy is a highly contagious but also highly immunizating disease. The bacillary leper in the propagator of the infection. However, close or prolonged contact with such bacillary casesis not necessary to acquire the infection. Hence, in endemic countries a large part of the population have been contaminated and immunized. Infection occurs naturally at younger ages, not because of special reciptivity in infancy, but rather because adults were already contaminated in their turn. (The author makes a distinction in childhood between "real" anergy and anergy of "non-infection"). A predisposition to leprosy exists, which is represented by an incapacity to react with the...

Estandarización de pruebas epicutáneas con aeroalergenos en la dermatitis atópica. Estudio multicéntrico / Patch test standarization with aeroallergens in atopic dermatitis. A multicentre study

En algunos pacientes con dermatitis atópica se ha demostrado que la aplicación directa de aeroalergenos sobre la piel es capaz de reproducir las lesiones características de la enfermedad. Por ello, si las pruebas epicutáneas fueran una técnica bien estandarizada, podrían constituir el modelo ideal de estudio alergológico en estos pacientes. El objetivo de este estudio fue determinar la concentración óptima para pruebas epicutáneas con varios aeroalergenos. Material y métodos: Se seleccionaron 137 pacientes con dermatitis atópica y 32 controles atópicos > 12 años en los 10 centros participantes en el estudio. Se realizaron pruebas del prick y pruebas epicutáneas con extractos de D. pteronyssinus, P. pratense, O. europaea, Alternaria alternata y epitelio de gato en concentraciones de 10, 5 y 1 HEP (Laboratorios DIATER®) y se determinó la IgE específica en el suero frente a aquellos alergenos positivos en el prick. Resultados: Los grupos de pacientes y controles fueron homogéneos. Obtuvimos un 25,7% y 9% de parches positivos con 10 HEP de D. pteronyssinus en pacientes y controles, respectivamente. Con O. europaea sólo hubo un 3% de pacientes y controles con un parche positivo. Con el resto de los alergenos la frecuencia de parches positivos en los pacientes fue del 11,2%, 8,8% y 7,5% frente a P. pratense, A. alternata y gato, respectivamente, y del 3% en los controles. Conclusión: La concentración más alta utilizada de 10 HEP con D. pteronyssinus puede considerarse adecuada para las pruebas epicutáneas. Respecto a los otros alergenos, esta concentración parece encontrarse por debajo de la óptima, sobre todo en el caso de O. europaea

In some patients with atopic dermatitis, characteristic eczematous skin lesions can be induced by patch testing with aeroallergens. However, atopy patch test is not well standardised. The aim of this study was to stablish the optimal concentration of aeroallergens for patch testing. Material and methods: We selected 137 patients with atopic dermatitis and 32 atopic controls in the 10 participant centres. Prick test and atopy patch test with D. pteronyssinus, P. pratense, O. europaea, A. alternata and cat dander extracts at 10, 5 and 1 HEP (DIATER S.A.) as well as specific IgE determination were performed. Results: The groups of patients and controls were homogeneous. A 25,7% and 9% of patients and controls, respectively, had a positive result when patch testing with D. pteronyssinus extract at 10 HEP. Only a 3% of positive patch tests were obtained with O. europaea in patients and controls. The frequency of positive patch tests with the other allergens in patients was 11,2%, 8,8% y 7,5% for P. pratense, A. alternata and cat dander, respectively, and 3% in controls. Conclusions: The highest concentration of 10 HEP could be considered optimal for the atopy patch test with D. pteronyssinus. Such concentration seems to be lower than the optimal one when patch testing the other allergens

Alergia al polen de las oleáceas en un lugar donde no hay olivos / Oleaceae pollen allergy in a place where there’s no olive trees

Antecedentes y objetivos: El polen del fresno (Fraxinus excelsior), árbol perteneciente a la familia Oleaceae, se ha descrito recientemente como un alérgeno relevante en algunos países centroeuropeos. El objetivo de este trabajo es estudiar la importancia que este polen tiene como factor desencadenante de los síntomas alérgicos que sufren, al final del invierno y principio de la primavera, algunos pacientes que viven en País Vasco, donde no existen olivos pero el fresno es un árbol abundante. Métodos: Se seleccionaron 48 pacientes que se clasificaron en tres grupos en función de la sensibilización predominante: pacientes alérgicos a oleáceas (O), alérgicos a gramíneas (G) y alérgicos a ambos pólenes (M). Los pacientes se dividieron además en dos grupos en función de la época en la que tenían los síntomas: pacientes con síntomas tempranos o pacientes con síntomas tardíos. Se les realizó la prueba del prick con una batería de pólenes, pruebas de exposición conjuntival con extractos de polen de olivo y de fresno y la determinación de IgE específica (EAST) frente a varios pólenes. Resultados: En el grupo O, el 100% de los pacientes tuvo síntomas tempranos, esto es, coincidiendo con la floración del fresno y antes de aparecer el polen de las gramíneas. En los grupos M y G los porcentajes de pacientes con síntomas tempranos fueron del 40% y 16%, respectivamente. Las pruebas de provocación conjuntival con polen de olivo y fresno resultaron positivos en el 100% y 70%, respectivamente, de los pacientes del grupo O, en el 78% y 50% del grupo M y en el 58% y 31% del grupo G. Los pacientes con síntomas tempranos tuvieron con mayor frecuencia pruebas cutáneas positivas frente al polen de F. excelsior (p < 0,05) y unas concentraciones de IgE específica frente a F. excelsior significativamente mayores (p < 0,05) que los pacientes con síntomas tardíos. Las pruebas de provocación conjuntival con polen de O. europaea fueron de mayor intensidad en los pacientes con síntomas tempranos. Conclusión: Los pacientes que residen en País Vasco y sufren síntomas durante el final del invierno y el comienzo de la primavera tenían una sensibilización predominante al polen del fresno y del olivo, en comparación con los pacientes que únicamente tenían síntomas tardíos (en mayo y junio). El polen del fresno puede considerarse una posible causa de polinosis en aquellos lugares donde su presencia es frecuente

Background: Ash tree belongs to the Oleaceae family; it has been recently described as a relevant allergen in some countries. The aim of this study is to demonstrate the importance of the ash pollen as a triggering factor of the allergic symptoms showed in early spring by a group of patients who live in the Basque Country, where ash are common trees and olive trees are not present. Methods: In accordance with their predominantly sensitisation we selected and classified 48 pollen-allergic-patients in three groups: oleaceae allergic patients (O), grass allergic patients (G) and oleaceae + grass allergic patients (M). Patients were also divided in two groups depending on the season when they showed the symptoms: patients with early or late symptoms respectively. Skin prick tests (SPT) and specific IgE (EAST) to Olea, Fraxinus and Lolium, patient’s scores of symptoms and rescue medication between February and July 2000, and conjunctival challenge tests with ash and olive pollen extracts were performed. Results: 100% of O patients, 40% of M patients and 16% of G patients suffered from early symptoms, coinciding with the flowering of ash, when grass pollen is not present yet. Conjunctival challenge tests with ash and olive pollen extracts were positive in 70% and 100% respectively in O patients, 50% and 78% in M patients and 31% and 58% in G patients. Conjunctival challenge tests in patients who suffered from early symptoms with olive extract were positive with lower concentrations of the extract. The patients with early symptoms had a higher rate of positive SPT with ash pollen (p < 0,05) and had significant higher levels of specific IgE to F. excelsior pollen (p < 0,05) than late symptomatic patients. Conjunctival challenge test to O. europaea pollen produced more symptoms to patients with early symptoms. Conclusion: Patients living in the Basque Country and suffering from symptoms during early spring had a predominant sensitisation to ash and olive pollen compared to those patients showing only late symptoms. Ash pollen can be considered as a potentially cause of hay fever in these areas where it is present in considerable amounts

Sensibilizaçäo a aeroalérgenos em crianças e adolescentes atópicos em Belo Horizonte, MG: comparaçäo da estimativa de IgE específica ® in vivo ¼ versus ® in vitro ¼ / Sensibilization to aeroallergens among aopic children in Belo Horizonte, MG: comparison between ® in vivo¼ specific IgE estimation

Objetivo: Este estudo transversal controlado teve como objetivo determinar, em uma amostra da populaçäo de crianças e adolescentes da regiäo metropolitana de Belo Horizonte com asma brônquica e/ou rinite alérgica e em controles, a freqüência com que a reatividade cutânea a estes aeroalérgenos esteve presente nos doisgrupos. Métodos: Avaliou-se 227 crianças e adolescentes com idade entre três e 19 anos (150 casos e 77 controles) através da aplicaçäo de questionário padronizado, do teste cutâneo por puntura a diferentes aeroalérgenos e do exame físico. Considerou-se positivo o teste cuja pápula do alérgeno testado foi, no mínimo, 3mm maior do que aquela produzida pelo controle negativo. Dosou-se também, no soro de 98 pacientes (67 casos e 31 controles). IgE específica para antígenos (RAST) de Blomia tropicalis (Bt) e Dermatophagoides pteronyssinus (Dp). Resultados: A positividade cutânea, pelo menos um alérgeno, esteve presente em 90 por cento dos casos e em 35 por cento dos controles (p=0,00). Respectivamente entre casos e controles, a positividade cutânea aos aeroalérgenos testados foi: Dp, 78,7 por cento e 11,3 por cento; Dermatophagoides farinae (Df), 74,0 por cento e 9,1 por cento; Bt, 64,0 por cento e 13,0 por cento; Lepidoglyphus destructor (Ld), 36,0 por cento e 6,5 por cento; Euroglyphus maynei (Em), 47,3 por cento e 9,1 por cento; Tyrophagus putrescentiae (Tp), 31,3 por cento e 7,8 por cento; Glycyphagus domesticus (Gd), 23,3 por cento e 5,2 por cento; Periplaneta americana (Pa), 40,0 por cento e 16,9 por cento; Alternaria/ Hormodendrum (AH), 17,3 por cento e 2,6 por cento; epitélio de gato, 18,0 por cento e 3,9 por cento; epitélio de cäo, 12,7 por cento e 9,1 por cento. Excetuando-se este último (p=0,561), em todos os outros antígenos verificou-se diferença estatisticamente significativa entre os dois grupos (p<0,001). Os três primeiros alérgenos provocaram os maiores percentuais de positividade, sugerindo serem estas espécies de ácaros os alérgenos mais prevalentes e relevantes à patogenia das doenças alérgicas respiratórias nesta populaçäo. Considera-se a possibilidade de ter ocorrido reatividade cruzada principalmente entre os dois primeiros alérgenos. Observou-se a ocorrência de indivíduos monossensibilizados a Bt e Pa. Pela primeira vez, documentou-se sensibilizaçäo a antígenos de Ld, Em e Tp em uma amostra da populaçäo atópica de Belo Horizonte. Demonstrou-se correlaçäo positiva entre a dosagem de IgE específica...

Estudio clínico y alergológico en pacientes con manifestaciones cutáneas minor de dermatitis atópica / Clinical and alergological study in patients with 'minor' cutaneous manifestations of atopic dermatitis

Antecedentes: los signos menores de dermatitis atópica pueden ser la única manifestación del proceso o formar parte del cuadro florido. Su importancia para el diagnóstico ha sido objeto de múltiples trabajos. Objetivo: relacionar las manifestaciones cútaneas menores de dermatitis atópica con la constitución atópica, historia personal y familiar y la interrelación con los factores medioambientales. Métodos: se investigó a 50 niños con manifestaciones atópicas menores, mediante exploración clínica, analítica y pruebas epidérmicas e intradérmicas (true test, ácaros, alimentos). Conclusiones: los criterios menores parecen ser indicadores de la constitución atópica más que del eccema atópico; en éste, el medio ambiente y la herencia influyen de forma importante. Los eosinófilos y la IgE no se relacionaron con la intensidad del proceso cutáneo, sino con la intensidad del proceso respiratorio y la reactividad a los ácaros. Los alimentos no tuvieron relación con las manifestaciones cutáneas (AU)