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Atopy Patch Test (atopy + patch_test)
Selected AbstractsAtopy patch test in patients with atopic eczema/dermatitis syndrome: comparison of petrolatum and aqueous solution as a vehicleALLERGY, Issue 4 2004J. M. Oldhoff Background:, The atopy patch test (APT) is an in vivo model to study the induction of eczema by inhalant allergens. This study was designed to compare two commonly used APT methods. Methods:, In the first method, the allergen is dissolved in aqueous solution, which is applied on tape-stripped skin. In the second method, the allergen is dissolved in petrolatum and applied without tape stripping. Thirteen patients with atopic dermatitis sensitized to inhalant allergens were patch tested using both methods. Reactions were evaluated macroscopically and microscopically after 48 h. Results:, Nine out of 13 patients displayed a positive reaction for both methods. One patient had a positive APT for the aqueous method alone and three for the petrolatum method alone. Reactions were significantly stronger when using the petrolatum method. Histological evaluation of the nine patients positive for both methods showed no significant differences in number of eosinophils, T-cells and neutrophils. Conclusion:, The APT using the petrolatum vehicle induces a higher number of positive reactions and is significantly stronger relative to the APT using allergen in aqueous vehicle. The cellular influx in both test methods is comparable. Both methods can be used to study the mechanisms in the induction of eczema by inhalant allergens. [source] Atopy patch tests with aeroallergens in children aged 0,3 years with atopic dermatitisALLERGY, Issue 8 2008A. C. A. Devillers No abstract is available for this article. [source] A method for the analysis of milk and egg allergens for the atopy patch testEXPERIMENTAL DERMATOLOGY, Issue 10 2009Cinzia Ballabio Abstract:, The patch test with food antigens (atopy patch test, APT) has been reported as a more specific method than prick or RAST for the early detection of cow's milk and/or egg sensitizations in children. Standardization of APT extracts is a major issue on the road towards full clinical exploitation of this assay. Here, we used sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to characterize sensitivity and specificity of commercial preparations of APT for milk and egg allergies, which are expected to improve the reliability of this test, when compared with fresh food allergen sources. We found that: (i) SDS-PAGE is an appropriate technique for quality control of APT and (ii) commercial milk and egg APT are equivalent to fresh food preparations in terms of allergen content. Clinical trials aimed at characterizing sensitivity and specificity of APT in the diagnosis of food allergy in children will benefit from this technique. [source] Tomato atopy patch test in adult atopic dermatitis: diagnostic value and comparison among different methodsALLERGY, Issue 4 2009E. Di Leo Tomato atopy patch test in adult atopic dermatitis. [source] Epicutaneous aeroallergen sensitization in atopic dermatitis infants , determining the role of epidermal barrier impairmentALLERGY, Issue 2 2008F. Boralevi Background:, Sensitization to atopens is an early phenomenon that overlaps with the onset of atopic dermatitis (AD) in infancy. Early epidermal barrier impairment may facilitate the epicutaneous penetration of atopens. Objective:, To correlate transepidermal water loss (TEWL) and aeroallergen sensitization in infants with AD. Methods:, In this cross-sectional study we enrolled 59 AD children and 30 controls aged 3,12 months. Transepidermal water loss in uninvolved skin, specific immunoglobulin E, atopy patch test (APT) and skin prick tests were performed with respect to seven aeroallergens, i.e., Dermatophagoides pteronyssinus, D. farinae, cat, dog, birch pollen, ambrosia, and cockroach. Environmental conditions were assessed by a questionnaire, and the house dust mite (HDM) concentration was determined in dust samples. Results:, Eighty-nine percent of AD infants had a positive APT vs one out of eleven controls. AD infants had a significantly higher mean TEWL than controls (27.4 vs 11.1 g/m2/h, P < 0001). Children with two or more positive APT had higher TEWL than the others (31.1 vs 19.0 g/m2/h, P < 0.025). No correlation was found between indoor APT results and exposure to HDM, cats, and dogs at home. Conclusions:, This study confirms the high prevalence of delayed sensitization to indoor and outdoor aeroallergens in AD infants, and shows that the higher the TEWL, the higher the prevalence of sensitization to aeroallergens. These data are in favor of a major role of a constitutive epidermal barrier impairment in determining early atopen sensitization in infants with AD. [source] Modulation of the atopy patch test: tacrolimus 0.1% compared with triamcinolone acetonide 0.1%ALLERGY, Issue 5 2006J. M. Oldhoff Background:, The atopy patch test (APT) is an in vivo model to study the induction of eczema by inhalant allergens in atopic dermatitis patients. We studied the effect of pretreatment with topical tacrolimus 0.1% on APT in nonlesional skin of patients with atopic dermatitis. Methods:, Nonlesional skin of the back of patients with atopic dermatitis (n = 8) was treated once daily for 3 weeks with tacrolimus 0.1% ointment. Cetomacrogol ointment (placebo) was used as a negative control and triamcinolone acetonide 0.1% ointment as positive control. Twenty-four hours after the last APT application, samples were taken from the three treated areas (t = 0 and 24 h) for immunohistochemical analysis. Results:, Pretreatment with tacrolimus ointment did not suppress nonlesional skin infiltrate, in contrast to triamcinolone acetonide. Furthermore, tacrolimus did not inhibit the induction of the APT macroscopically (t = 24 h). An equal influx of T cells, eosinophils, dendritic cells, CD64+ and Fc,RI-positive cells was present compared with placebo. Only CD36+ and CD68-positive cells were inhibited compared with placebo. All cell types were significantly inhibited in triamcinolone acetonide-treated sites compared with placebo. Conclusions:, Pretreatment with tacrolimus 0.1% ointment does not inhibit the APT reaction in patients with atopic dermatitis. [source] Delayed- and immediate-type reactions in the atopy patch test with food allergens in young children with atopic dermatitisPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 1 2009A. C. A. Devillers In recent years, the atopy patch test (APT) has been suggested as an addition in the allergological work-up of children with atopic dermatitis (AD) and suspected food allergy. We initiated a prospective clinical study in children with AD younger than 3 yr, to evaluate the additional clinical value of the APT next to our own standardized allergological work-up in case of a suspected food allergy. One hundred and thirty-five children were included in the study. They were tested using the skin application food test (SAFT), the APT and measurement of specific IgE. The allergens used in the skin tests were freshly prepared food stuffs and included commercially available cow's milk (CM), the egg white of a hard boiled hen's egg and mashed peanuts in a saline solution. Allergy was defined using a flowchart incorporating the results from the SAFT, oral challenges (OCs) and elimination and (re)introduction periods. To determine the additional value of the APT next to the SAFT, we analyzed the SAFT negative patients per allergen and used an exact binary logistic analysis to evaluate the simultaneous effects of the APT and measurement of specific IgE, calculating mutually adjusted odds ratios (ORs) for positive APTs and specific IgE levels above 0.70 U/l. We found clinically relevant food allergies in 23% (egg white) to 28% (CM and peanut) of our study population. Positive SAFT reactions were observed in 14% (peanut), 16% (egg white) and 21% (CM) of our patient population. Next to the SAFT, we did not observe a significant additional value of the APT for the diagnosis of CM or egg white allergy, but we did find a significant additional value for the diagnosis of peanut allergy (OR = 11.56; p < 0.005, 2-sided). In clinical practice this statistically significant value does not exclude the need for OC and controlled elimination and (re)introduction periods due to the presence of false-negative as well as false-positive results in the APT. In conclusion, we could not find enough support for the current addition of the APT to our standardized allergological work-up in young children below the age of 3 yr with AD and suspected food allergy. At the moment the additional value of the classical delayed-type APT next to the SAFT seems to be very limited at best in this study population and does not justify the time-consuming nature of the skin test. [source] Unnecessary Milk Elimination Diets in Children with Atopic DermatitisPEDIATRIC DERMATOLOGY, Issue 1 2007J.L. Sinagra M.D. We investigated the percentage of children allergic to cow's milk compared with the rate of milk exclusion diets in a group of patients with atopic dermatitis. We enrolled 206 children (79 girls, 127 boys), mean age 45.8 (4,68) months, affected by atopic dermatitis into our study. All children underwent radioallergosorbent test for casein, alpha-lactalbumin and beta-lactoglobulin, prick test, atopy patch test, and oral provocation test. Children were followed up at 1, 3, 6, and 12 months. Of the 206 patients, 20 were excluded from statistical analysis, leaving 186. Forty-five (24.2%) were on a milk elimination diet and 141 on a normal diet. Four patients on the milk-free diet (8.9%), accounting for 2.2% of all patients, were found to be allergic. In the others, milk reintroduction did not cause the disease to worsen during the follow-up period. No children on a normal diet were found to be allergic. Our results demonstrated an actual prevalence of cow's milk allergy in patients on milk elimination diets (4%) to be significantly lower than the number of patients prescribed such diets (24.2%),confirming that this measure is being applied excessively. [source] Regulatory T cells in atopic dermatitis: epidermal dendritic cell clusters may contribute to their local expansionBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2009A. Szegedi Summary Background, Regulatory T cells (Tregs) have an essential role in tolerance and immune regulation. However, few and controversial data have been published to date on the role and number of these cells in atopic dermatitis (AD). Objectives, To investigate the number of CD4+CD25+FOXP3+ Tregs and interleukin 10-producing T regulatory type 1 (Tr1) cells in patients with AD. Methods, Peripheral blood and skin biopsy samples from atopy patch test (APT)-positive patients with acute- and chronic-phase AD were investigated. Immunohistochemistry was applied to identify CD4+CD25+FOXP3+ Tregs in the skin, while flow cytometry was used to detect CD4+CD25highFOXP3+ Tregs and Tr1 cells in the peripheral blood. Results, In the peripheral blood samples of patients with AD significantly elevated numbers of Tr1 cells were found. Although neither the absolute number nor the percentage of CD4+CD25highFOXP3+ Tregs showed significant alteration in the peripheral blood of patients, increased numbers of FOXP3+ Tregs were detected in skin biopsy specimens. All of the APT-positive skin samples showed epidermal dendritic cell aggregates, morphologically consistent with so-called Langerhans cell microgranulomas, which also contained intermingled FOXP3+ Tregs. Conclusions, Tr1 cell numbers were elevated in the peripheral blood and increased numbers of CD4+CD25highFOXP3+ Tregs were detected in the skin of patients with AD. The epidermal dendritic cell clusters in APT-positive lesional skin showed a close connection to the FOXP3+ Tregs. [source] Influence of short-term exposure to airborne Der p 1 and volatile organic compounds on skin barrier function and dermal blood flow in patients with atopic eczema and healthy individualsCLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2006J. Huss-Marp Summary Background Epidemiological studies indicate environmental pollutants to be involved in the increase in the prevalence of allergic diseases. In human exposure studies, volatile organic compounds (VOCs) have been shown to cause exacerbations of allergic asthma whereas, no data concerning atopic eczema (AE) are available. Objective We investigated the effect of airborne VOCs on the skin of patients with AE and controls in the presence or absence of house dust mite allergen, Der p 1. Methods In a double-blind crossover study, 12 adults with AE and 12 matched healthy volunteers were exposed on their forearms to Der p 1 and subsequently to a mixture of 22 VOCs (M22, 5 mg/m3) in a total body exposure chamber for 4 h. Transepidermal water loss (TEWL) and skin blood flow were measured in all subjects before, during and after exposure. Additionally, an atopy patch test (APT) with Der p 1 was applied to the skin after exposure. Results A significant increase in transepidermal water loss was observed 48 h after exposure to VOCs as compared with exposure with filtered air in all individuals (mean difference: +34%; 95% Confidence Interval: 7,69%). Prior Der p 1 exposure resulted in a significant rise of dermal blood flow after 48 h in patients with AE but not in controls. Six out of seven patients showed enhanced atopy patch test (APT) reactions to HDM allergen after previous exposure to VOCs. Conclusion Our results show that exposure to VOCs , at concentrations commonly found in indoor environments , can damage the epidermal barrier and enhance the adverse effect of Der p 1 on sensitized subjects with AE. These findings may contribute to a better understanding of the mechanisms underlying the increase in prevalence and exacerbation of AE. [source] |