Prevalence of positive atopy patch test in an unselected pediatric population

Atopic dermatitis in schoolchildren and adolescents: a critical review of Italian epidemiological data and systemic treatments

INTRODUCTION

The epidemiology of atopic dermatitis (AD) is largely different in pre-school and schoolchildren. We summarized the available epidemiological data on schoolchildren (6-11 years) and adolescents (12-17 years) in Italy and reviewed information on systemic treatments for moderate-to-severe AD in adolescents.

EVIDENCE ACQUISITION

In January 2019, we searched for data on prevalence and/or incidence of AD and on the efficacy, effectiveness and safety of systemic AD therapies. Papers were evaluated and selected, and relevant information was extracted. Twenty papers from 17 studies reported original epidemiological information on AD in Italy.

EVIDENCE SYNTHESIS

Most studies were conducted before 2005. Though variations emerged between studies, the lifetime prevalence of AD was estimated between 15-17% in schoolchildren and between 8-13% in adolescents. The (12-months) period prevalence of AD was estimated between 8-10% in children and between 8-11% in adolescents. Up-to-date information on the prevalence of severe AD is not available. Cyclosporine A may be used in pediatric age patients (children and adolescents) with persistent or severe AD refractory to topical treatments, but its use has several limitations, and is not recommended in patients younger than 16 years. The treatment paradigm of AD is still far from being satisfactory.

CONCLUSIONS

We provided a quantitative synthesis of AD epidemiology in Italian schoolchildren and adolescents. Recent data are needed, as most information dates back to the 1990s or early 2000s, and data on the incidence of AD, the proportion of severe cases, and treatment of severe cases in the real-world setting are scanty.

Brazilian experience with atopy patch tests for Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis

Background

The aim of this study was to evaluate the positivity rates of atopy patch tests for Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis in patients with respiratory diseases such as asthma and allergic rhinitis with or without atopic dermatitis.

Methods

The patients’ clinical histories were collected, and the patients were subjected to skin prick and patch tests with the three different house dust mites on the same day. The patch tests were examined 48 hours later, and then patients were divided into two groups: I- patients with respiratory diseases, such as asthma and/or rhinitis, and atopic dermatitis and II-patients with only respiratory diseases. A total of 74 patients ranging in age from 2 to 60 years were included in this study; 16 patients were included in group I and 58 were included in group II. This study was approved by the human ethics committee of the Faculty of Medical Science and Health SUPREMA (number 2.007.135), and written informed consent was collected from each patient or their parents prior to enrollment.

Results

In the skin prick tests, the most prevalent mite that evoked a reaction was Dermatophagoides pteronyssinus, followed by Dermatophagoides farinae and Blomia tropicalis. Regarding the atopy patch tests, the mite that most frequently induced a positive reaction was Dermatophagoides farinae (78.4%), followed by Dermatophagoides pteronyssinus (77%) and Blomia tropicalis (52.7%). A comparison of the skin prick and atopy patch tests revealed that 53 patients (71.6%) were positive on both tests, and 30 (56.6%) patients were positivite for the same mite. We found six patients (8%) who had a positive clinical history of allergy and only exhibited positivity on the atopy patch test.

Discussion

Most studies have been performed with atopic dermatitis patients, but in this study, most of the patients had respiratory conditions. Blomia tropicalis is a mite that is prevalent in tropical areas, such as Brazil, and only two publications include these three mites, wich are present in Brazil. The APT may produce positive results in concordance with the SPT resuts, but may also be the only positive test ( 8%) as we observed in our study. These results suggest that the mite atopy patch test is relevant and should be considered as an additional test for patients with clinical histories of allergic respiratory disease who have negative prick test results.

Conclusion

The APT should be considered as an additional test when the SPT and specific serum IgE tests are negative in patients with clinical histories of allergies.

The Incidence of Delayed-Type Hypersensitivity Reactions to Apples Among Patients Allergic to Birch Pollen

The major apple allergen Mal d 1 cross-reacts with the homologous birch pollen allergen Bet v 1 and causes immunoglobulin E (IgE)-mediated immediate-type allergic reactions. In some patients, delayed-type hypersensitivity to apples may develop within 72 hours without evidence of specific IgE or a positive skin prick test (SPT). The aim of the study was to evaluate the concomitance of delayed-type hypersensitivity reactions and immediate IgE-mediated reactions against high- and low-allergenic apple cultivars in patients with birch pollen allergy. Data were obtained from 45 adults with clinical symptoms of birch pollen allergy. Patients were exposed to apple pulp via atopy patch tests (APTs) and SPTs. Levels of IgE specific to Bet v 1 and Mal d 1 were measured with a radioallergosorbent test. Patients allergic to birch pollen showed the highest rate of positive SPT responses to Golden Delicious apples and the lowest rate to low-allergenic cultivar Grey French Reinette. Among these patients, 9% developed delayed hypersensitivity reactions to either Golden Delicious or Grey French Reinette apples; these reactions manifested clinically as erythema with papules (class ++). Fifty percent of APT-positive patients were concomitantly SPT-negative. Here, we show for the first time the clinical relevance of T cell-driven allergic reactions to apples. APTs may reveal type IV sensitization in patients who are negative for the corresponding type I sensitization tests. Thus, utilization of the APT procedure with fresh apple appears to be a valuable tool for the diagnosis of apple allergy and may improve the accuracy of food allergy diagnoses.

Utility of the Atopy Patch Test in the Diagnosis of Allergic Rhinitis

INTRODUCTION

The diagnostic work-up of allergic rhinitis (AR) is first and foremost based on the combination of clinical history data and results of skin prick tests (SPT). Other tests, including specific IgE measurement, nasal challenge, and, as a third option, component resolved diagnosis or basophil activation test, may be useful when the diagnosis is difficult because of polysensitization or when negative results of SPT are observed despite a suggestive history for allergy. The atopy patch test (APT) that assesses the type 4 delayed hypersensitivity allergy is currently not sufficiently used. The data obtained in recent studies on the diagnostic utility of the APT in patients with AR was reviewed.

DATA SOURCES

Review of the literature.

CONCLUSION

The data from available studies show that the APT is frequently positive in patients with AR, especially when there is a positive history for atopic dermatitis. Very often, APT is the only positive test and therefore performing only SPT or in vitro IgE measurement may lead to an erroneous diagnosis of nonallergic rhinitis. Recent data suggest a role for APT not only for diagnosis but also in epidemiological investigation on respiratory allergy.

Cutaneous exposure to agglomerates of silica nanoparticles and allergen results in IgE-biased immune response and increased sensitivity to anaphylaxis in mice

Background

The skin is a key route of human exposure to nanomaterials, which typically occurs simultaneously with exposure to other chemical and environmental allergen. However, little is known about the hazards of nanomaterial exposure via the skin, particularly when accompanied by exposure to other substances.

Results

Repeated topical treatment of both ears and the shaved upper back of NC/Nga mice, which are models for human atopic dermatitis (AD), with a mixture of mite extract and silica nanoparticles induced AD-like skin lesions. Measurements of ear thickness and histologic analyses revealed that cutaneous exposure to silica nanoparticles did not aggravate AD-like skin lesions. Instead, concurrent cutaneous exposure to mite allergens and silica nanoparticles resulted in the low-level production of allergen-specific IgGs, including both the Th2-related IgG1 and Th1-related IgG2a subtypes, with few changes in allergen-specific IgE concentrations and in Th1 and Th2 immune responses. In addition, these changes in immune responses increased the sensitivity to anaphylaxis. Low-level IgG production was induced when the mice were exposed to allergen–silica nanoparticle agglomerates but not when the mice exposed to nanoparticles applied separately from the allergen or to well-dispersed nanoparticles.

Conclusions

Our data suggest that silica nanoparticles themselves do not directly affect the allergen-specific immune response after concurrent topical application of nanoparticles and allergen. However, when present in allergen-adsorbed agglomerates, silica nanoparticles led to a low IgG/IgE ratio, a key risk factor of human atopic allergies. We suggest that minimizing interactions between nanomaterials and allergens will increase the safety of nanomaterials applied to skin.

Electronic supplementary material

The online version of this article (doi:10.1186/s12989-015-0095-3) contains supplementary material, which is available to authorized users.