Search

Background: The relationship between sensitization to Dermatophagoides species and solar irradiation, as reflected by vitamin D, remains elusive. Objective: We investigated the lag time and the cumulative and maximum effects of exposure to solar irradiation on sensitization to house-dust mites. Methods: A time series study design was applied to solar irradiation (MJ/m2) and relative humidity (%) for specific immunoglobulin E (IgE) levels against Dermatophagoides pteronyssinus (n = 20,451) and Dermatophagoides farinae (n = 22,824). We used the distributed lag nonlinear model to assess the difference of log IgE to house-dust mites in relation to climate variables. Results: Compared with specific IgE levels of those exposed to 18 MJ/m2, the maximum increase in sensitization to D. pteronyssinus was observed at a solar irradiation of 10 MJ/m2 at peak 0 week (difference of log IgE 0.368 [95% confidence interval (CI), 0.209-0.529], p < 0.001), and this increase continued for 3 weeks. The IgE level was significantly affected by the relative humidity of the 3rd- to 12th-lag week, and the effect reached its peak at 75% on the 8th week (difference of log IgE 0.394 [95% CI, 0.221-0.566], p < 0.001). The logistic regression analysis showed that solar irradiation was associated with a decreased risk to sensitization to D. pteronyssinus (odds ratio 0.988 per 1 MJ/m2 [95% CI, 0.979-0.997], p < 0.013) on the testing week after controlling for humidity and temperature. Conclusion: This study demonstrated that low solar irradiation immediately increased the risk of sensitization to two house-dust mite species. Further research is warranted to delineate the underlying mechanism of the effect of solar irradiation on aeroallergen sensitization. [ABSTRACT FROM AUTHOR]

Background: Two different allergic rhinitis (AR) symptom phenotype classifications exist. Treatment recommendations are based on intermittent-persistent (INT-PER) cataloging, but clinical trials still use the former seasonal AR-perennial AR (SAR-PAR) classification. This study was designed to describe how INT-PER, mild-moderate/severe and SAR-PAR of patients seen by allergists are distributed over the different climate zones in a (sub)tropical country and how these phenotypes relate to allergen sensitization patterns. Methods: Six climate zones throughout Mexico were determined, based on National Geographic Institute (Instituto Nacional de Estadística y Geografía) data. Subsequent AR patients (2-68 years old) underwent a blinded, standardized skin-prick test and filled out a validated questionnaire phenotyping AR. Results: Five hundred twenty-nine subjects participated in this study. In the tropical zone with 87% house-dust mite sensitization, INT (80.9%; p < 0.001) and PAR (91%; p = 0.04) were more frequent than in the subtropics. In the central high-pollen areas, there was less moderate/severe AR (65.5%; p < 0.005). Frequency of comorbid asthma showed a clear north-south gradient, from 25% in the dry north to 59% in the tropics (p < 0.005). No differences exist in AR cataloging among patients with different sensitization patterns, with two minor exceptions (more PER in tree sensitized and more PAR in mold positives; p < 0.05). Conclusion: In a (sub)tropical country the SAR-PAR classification seems of limited value and bears poor relation with the INT-PER classification. INT is more frequent in the tropical zone. Because PER has been shown to relate to AR severity, clinical trials should select patients based on INT-PER combined with the severity cataloging because these make for a better treatment guide than SAR-PAR. [ABSTRACT FROM AUTHOR]

Background: In perennial allergic rhinitis (PAR), the skin-prick test (SPT) is a good diagnostic tool to identify the specific allergens. A nasal provocation test (NPT) is used to identify allergens and to confirm the diagnosis. The aim of this study was to determine the optimal cutoff values of symptom and peak nasal inspiratory flow (PNIF) changes after dust-mite NPT for predicting PAR. We also studied the relationship of the changes of symptoms in NPT and the wheal size of SPT. Methods: One hundred five patients with perennial rhinitis underwent the NPT to Dermatophagoides pteronyssinus and the SPT. The NPT was assessed by changes in symptoms and PNIF. The optimal cutoff values of the symptoms score and PNIF changes after the NPT for predicting the SPT were determined using a receiver operating characteristic (ROC) curve. The relationship of the wheal sizes of SPT and the changes from the NPT were analyzed. Results: Forty-eight patients had a positive SPT to D. pteronyssinus, of whom 33 patients had a positive NPT by increases of the symptom score. Twenty patients had a positive NPT by decreases of PNIF. The area under the ROC curve was 0.85 for symptom score changes and it was 0.612 for PNIF changes. There was a significant correlation between the wheal size of the SPT and symptom changes in the NPT. Conclusion: Nasal provocation is a valuable test to confirm the diagnosis of D. pteronyssinus allergy, especially when the wheal from the SPT is small. The symptom change after the house-dust mite NPT is better than the PNIF change for predicting the PAR. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the relationship between the house- dust mite allergy and prevalence of house-dust mites in dwellings of children who were tested for specific IgE against Dermatophagoides pteronyssinus (D. pteronyssinus) and D. farinae on the suspicion of allergic rhinitis, dermatitis and asthma. All dust specimens collected from children's houses were investigated under a light microscope. House-dust mites were found in 3 1.7% of houses of children with a specific IgE, while the rate was 27.5% in houses of those without a specific IgE. Overall, house dust specimens collected from a total of 92 houses were examined, and mites were found in 27 (29.3%) of them. Both Der p and Der f were found in 38 (92.7%), while mixed allergy (D. pteronyssinus + D. farinae) was found in 3 (7.3%). Der p allergy (100%) was found in all of the allergic children, while no child was found with specific IgE for Der f allergy, except in mixed allergies. [ABSTRACT FROM AUTHOR]

Allergic rhinitis induced by house dust mites (HDMs) is a highly prevalent but often underdiagnosed and undertreated/untreated chronic disease. It often has a negative impact on sleep, work, leisure activities, and health-related quality of life. Allergen immunotherapy is a proven, safe treatment for respiratory allergies. We sought to assess the efficacy and safety of a 300 index of reactivity (IR) sublingual tablet formulation of Dermatophagoides pteronyssinus : Dermatophagoides farinae 1:1 extract in adolescents (aged ≥12) and adults with moderate to severe HDM-induced allergic rhinitis. In a phase III, international, double-blind, placebo-controlled, randomized clinical trial, participants received approximately 12 months of treatment with placebo or the 300 IR tablet. The primary end point was the average total combined score during 4 weeks at the end of the treatment period. A total of 1607 participants were randomized, and 1476 (including 555 [37.6%] with concomitant mild controlled asthma at inclusion) comprised the full analysis set. Over the primary evaluation period, the least squares mean average total combined score in the 300 IR group (3.62) was significantly lower (P <.0001) than in the placebo group (4.35), with a relative least squares mean difference of −16.9% (95% CI, −24.0% to −9.2%). All prespecified secondary end points were consistently improved in the 300 IR group, relative to placebo. The 300 IR tablet was generally well tolerated. Treatment-related adverse events (mainly mild or moderate local reactions) were reported for 51.0% of the patients in the 300 IR group and 14.9% in the placebo group. The 300 IR sublingual HDM tablet is an effective, safe treatment for HDM-induced allergic rhinitis. [ABSTRACT FROM AUTHOR]