The atopy patch test: an increased rate of reactivity in patients who have an air-exposed pattern of atopic eczema

Summary In a subgroup of patients with atopic eczema (AE), eczematous skin lesions can he induced by epicutaneous testing with aeroallergens (the atopy patch test: APT). An increased frequency of positive APT has been found in AK patients showing a predictive lesional pattern affecting air-exposed skin areas. This study investigates the dose-response ofthe APT in two dilTerent patient groups with AE. Petrolatum preparations of house dust mite, cat dander and grass pollen allergens in four concentrations (500–10,000) protein nitrogen imits) were tested epicutaneously in 57 patients with AE. who were prospectively divided in two groups according to whether their AE pattern was with (group I) or without (group II) a predictive distribution. Sixty-nine per cent of patients in group I. and 39% in group II. had positive APT reactions (P = 0.02). The reactions in group I were elicitable with lower allergen concentrations (P = 0.03). A clinically recognizable subgroup of patients with AE showed increased cutaneous sensitivity to aeroallergens.     

The diagnostic value of atopy patch testing and prick testing in atopic dermatitis: facts and controversies

We conducted a systematic Medline search of the literature (1998-2008) on the criteria for performing the skin prick test and atopy patch testing (APT) to determine their utility in atopic dermatitis (AD). The skin prick, scratch, and skin patch tests are performed to identify which allergen is causing eczematous skin symptoms in patients with AD, or sneezing, nasal congestion, itchy eyes, wheezing, skin rash, and swelling. Many allergens in foods, drugs, and environmental substances (eg, ragweed and fungus), as well as contact allergens, can elicit eczematous skin reactions after epicutaneous application. Because no gold standard exists for aeroallergen provocation in AD, the APT is currently used to evaluate allergen without comparison with another accurate and reliable method. The APT is presumed to reflect delayed-phase clinical reactions. Even with delayed onset of symptoms (more than 2 hours after food ingestion), APT findings were not consistent among AD children. The APT could be used in children with gastrointestinal reactions to foods as well as AD. After standardization, the APT may provide further diagnostic information in addition to the skin prick test and serum immunoglobulin E values and may be able to evaluate the actual clinical relevance of immunoglobulin E-mediated sensitizations for eczematous lesions. The European APT model used with standardization of allergen concentration and vehicle may provide an important diagnostic tool to select patients for avoidance and for procedures of allergen-specific immunotherapy, but the clinical relevance of positive APT reactions awaits standardized provocation and avoidance testing.     

Atopie-Patch-Test mit Aeroallergenen und Nahrungsmitteln

The atopy patch test (APT), a patch test employing allergens known to elicit IgE-mediated reactions which is assessed by evaluating eczematous skin lesions after 24 h to 72 h, was developed as a diagnostic tool for characterizing patients with aeroallergen-triggered atopic eczema (AE, atopic dermatitis). Positive APT reactions are associated with allergen-specific T-cell responses. The specificity of APT is higher than the specificity of skin prick tests or RAST. More studies for the standardization of APT methods are necessary, especially with regard to food APT.     

Japanese cedar pollen as an exacerbation factor in atopic dermatitis: results of atopy patch testing and histological examination

Atopy patch testing with Japanese cedar pollen extract has been used to investigate patients with atopic dermatitis whose condition is exacerbated by contact with Japanese cedar pollen. Comparative atopy patch testing, scratch tests, and assays for total IgE and specific IgE were performed in 74 patients with atopic dermatitis, 5 patients with Japanese cedar pollinosis and 15 control subjects. A skin biopsy was performed on any sites that were positive to Japanese cedar pollen patch test. The results after 48 h of atopy patch testing were compared with the patient's history, skin scratch test and specific IgE. Twenty-two of the 74 patients (30%) had a history of exacerbation every spring after contact with Japanese cedar. Of these patients 68% showed a positive reaction to Japanese cedar pollen extract, as did 21% of patients with atopic dermatitis without a history of exacerbation by Japanese cedar pollen, 20% of patients with Japanese cedar pollinosis without eruption and 7% of control subjects. A histological examination revealed eczematous changes and infiltration of lymphocytes and eosinophils in atopy patch testing positive sites. In conclusion, atopy patch testing with Japanese cedar pollen extract is a useful method for investigating trigger factors for eczematous skin lesions in a subgroup of patients with atopic dermatitis.     

Comparative in situ topoproteome analysis reveals differences in patch test‐induced eczema: cytotoxicity‐dominated nickel versus pleiotrope pollen reaction

Please cite this paper as: Comparative in situ topoproteome analysis reveals differences in patch test‐induced eczema: cytotoxicity‐dominated nickel versus pleiotrope pollen reaction. Experimental Dermatology 2010; 19: 511–517. Abstract: A subgroup of patients with atopic eczema develops acute eczematous reactions to type I allergy‐inducing agents such as pollen that clinically resemble type IV allergies induced by haptens like metal ions. To clarify the underlying immunologic mechanisms, this study was designed to map the inflammatory in situ topoproteome of eczematous responses to grass/birch pollen and nickel by using atopy patch test (APT) and nickel patch test (NPT) as an appropriate clinical model, respectively. Biopsies from NPT (n = 6) and APT (n = 6) with positive reactions at 72 h were analysed by multiple epitope ligand cartography (MELC), which enabled to investigate coexpression of 49 different epitopes immunohistochemically in a single given tissue section. Colocalisation of IgE and FcεRI was investigated by confocal microscopy. Compared with APT responses, NPT reactions were dominated by cytotoxic TIA‐1 + and CD8 + T cells. In contrast, the immune response in APT reactions appeared more pleiotrope – as detected by colocalisation analysis. Multiple combinatorial molecular phenotype (CMP) motifs containing naive, early maturation and memory T cell (CD45RA, CD7, CD44, CD45R0), and general activation markers (CLA, HLA‐DR, CD13, CD29, CD58, CD71, CD138) were significantly higher expressed in APT when compared with NPT reactions. APT response was confirmed to be accompanied by IgE bound to FcεRI. In summary, our results demonstrate that the NPT reaction is clearly dominated by cytotoxic events, while the APT reaction to pollen grains is more heterogeneous and elicits a combined humoral and cellular immune reaction.     

43例季节性接触性皮炎皮肤试验研究

为探索季节性接触性皮炎病因及发病机理.我们对43例季节性接触性皮炎(季节组)患者进行花粉抗原斑贴试验等一系列皮肤试验研究,并设62例变态反应性接触性皮炎(非季节组)及50例健康组为对照。结果,季节组血清总IgE水平及阳性率、花粉抗原特异性IgE阳性率、花粉点刺及斑试阳性率均明显高于非季节组及健康组,特异性IgE与花粉抗原点刺及斑试反应间均有明显的相关性和较高的符合率。表明季节性接触性皮炎发病与花粉抗原诱导的IgE介导的迟缓相反应有关。     

The disturbance of epidermal barrier function in atopy patch test reactions in atopic eczema

Summary Atopic eczema (AE) is a common skin disorder. Eczematous lesions showing macroscopic, microscopic and immunopathological resemblance to lesional AE can be induced by aeroallergens by epicutaneous testing (atopy patch test, APT). Altered epidermal barrier function, as determined by transepidermal water loss (TEWL), is a typical feature of patients with AE. The present investigation was performed to define the differences in the epidermal barrier function between positive APT reactions to aeroallergens and positive patch test reactions to contact allergens in AE patients. Allergen extracts from grass pollen, birch pollen, cat dander and house dust mite (Dermatophagoides pteronyssinus) were applied in large Finn chambers on Scanpor for 48h on the clinically unaffected and untreated skin of the back, in 11 patients with AE. The same procedure was done with 27 contact allergens of a standard test battery. Test reactions were read and TEWL was measured after 48 and 72h. Eight of the 11 patients developed positive APT reactions toD. pteronyssinus, two to cat dander and one to birch pollen. Seven of the 11 patients showed positive patch test reactions to nickel sulphate, two to potassium dichromate, one to thiuram-mix and one to paraphenylenediamine. Vehicle controls were negative. The TEWL of the positive APT reactions was significantly higher, both after 48 h (mean ± standard deviation 10·0±6·5 g/m²h) and after 72 h (9·7±5·4g/m²h) as compared with the control site (48/72h: 4·4±1.5/4·1±1·4 g/m²h) (P<0·01). In contrast, TEWL of the positive patch test reactions to contact allergens (48/72h; 5·4±2·2/5·4±1·9g/m²h) was similar to that of the control site (48/72 h: 5·2±2·1/5·0± 1·8g/m²h) (not significant). The relative TEWL at 48 h and 72 h, expressed as the ratio between the positive patch test and the control site, was significantly higher in the positive APT reactions (48/72 h: 218·8±80·4%/232·0±85·9%) compared with positive patch test reactions to contact allergens (48/72 h: 102·1±12·0%/107·1±9·5%) (P<0·01). It is concluded that the epidermal barrier function in AE patients is altered only in positive APT reactions, in contrast to positive patch test reactions to contact allergens. As a consequence of this aeroallergen-induced altered epidermal barrier function, further allergens can more easily penetrate the skin, inducing a vicious circle and perpetuating the eczematous lesions.     

Atopy patch test reaction to airborne allergens in the diagnosis of atopic dermatitis

The aim of the study was to evaluate the possible use of atopy patch test in the diagnosis of atopic dermatitis and to characterize an optimal standardized system for atopy patch test in terms of allergen concentrations and time of allergen exposure. The study included 36 patients with atopic dermatitis and IgE-mediated airborne allergy. Patients presented positive results of skin prick tests and serum antigen specific IgE against house dust mite allergens and/or selected grass pollen allergens. Control groups consisted either of patients with allergic rhinitis (control group 1) or healthy volunteers with no signs or symptoms of atopy (control group 2). Allergologic diagnostic workup consisted of skin prick test, serum antigen specific IgE and total IgE evaluation, atopy patch test with selected airborne allergens of different concentrations (0.1xSPT, 1xSPT and 10xSPT), time of allergen exposure (8, 24 and 48 h), and readings of the results (8, 24, 48 and 72 h). Positive results of atopy patch test with airborne allergens were obtained in 47.2% of atopic dermatitis patients and none of control subjects. Contact reaction itself and the intensity of reaction were demonstrated to correlate with allergen concentration and time of allergen exposure on atopy patch test. The dose and time response analysis showed the optimal concentration of allergens for atopy patch test to be 10xSPT, 500000 SBE/ml, and optimal evaluation time 24 and 48 h of allergen application. There was no correlation between atopy patch test results and mean serum concentrations of total or antigen specific IgE. Atopy patch test results did not correlate with localization of skin lesions, severity and extensiveness of skin inflammation. A significantly higher contact reactivity to airborne allergens was recorded in the group of atopic dermatitis patients with polyvalent allergy in comparison with atopic dermatitis patients allergic to only one aeroallergen. It is concluded that atopy patch test is the only provocation test currently available with clinical relevance for contact IgE-mediated sensitization in atopic dermatitis patients. Using petrolatum as a vehicle, allergen concentration of 500000 SBE/ml and evaluation time of 24 and 48 h of allergen application may lead to improved atopy patch test results.     

Positive atopy patch test reaction to Malassezia furfur in atopic dermatitis correlates with a T helper 2-like peripheral blood mononuclear cells response

The yeast Malassezia furfur belongs to the normal cutaneous flora, but is also a triggering allergen that can contribute to atopic dermatitis. To illuminate the effect of circulating allergen-specific T cells in atopic dermatitis, the peripheral mononuclear cell response was correlated with the in vivo skin prick test and atopy patch test reactivity to M. furfur. None of 16 healthy controls showed any positive in vivo reaction. The 40 atopic dermatitis patients, of whom 18 had serum IgE reactivity to M. furfur, were subdivided according to their in vivo reaction to M. furfur extract into three groups: skin prick test positive/atopy patch test positive (n = 12), skin prick test positive/atopy patch test negative (n = 12), and skin prick test negative/atopy patch test negative (n = 16). The skin prick test positive/atopy patch test positive and the skin prick test positive/atopy patch test negative groups had a significantly higher peripheral mononuclear cell stimulation index than the healthy controls. Interestingly, the stimulation index values in the skin prick test positive/atopy patch test positive group were significantly higher than in the skin prick test positive/atopy patch test negative group. In the M. furfur skin prick test positive atopic dermatitis patients (n = 24) a correlation was found between stimulation index and the M. furfur atopy patch test reactions, but not between stimulation index and M. furfur-specific serum IgE levels. Skin prick test positive and/or atopy patch test positive reactions to the recombinant M. furfur allergens rMal f 1, rMal f 5, and rMal f 6 were observed in 7, 14, and 16 of the 40 atopic dermatitis patients, respectively. Further, there was a correlation between production of the T helper 2-related cytokines interleukins 4, 5, and 13 and stimulation index to M. furfur extract, but not between the T helper 1-related interferon-gamma and stimulation index to M. furfur extract. Our data strongly suggest a relationship between circulating specific T cells with a T helper 2-like cytokine profile and positive atopy patch test reactions.     

Component-resolved diagnosis (CRD) of type I allergy with recombinant grass and tree pollen allergens by skin testing

The diagnosis of Type I allergy is based on the measurement of allergen-specific IgE antibodies and on provocation with allergens, most frequently conducted by skin testing. Both forms of diagnosis are currently performed with allergen extracts that are difficult to standardize regarding their allergen contents, and which contain additional undefined nonallergenic components. We report the expression in Escherichia coli and purification of some of the most relevant timothy grass- and birch pollen allergens. Recombinant timothy grass- (rPhl p 1, rPhl p 2, rPhl p 5) and birch pollen (rBet v 1, rBet v 2) allergens were purified and used for the measurement of allergen-specific IgE and IgG subclass responses as well as for skin prick testing in 55 pollen allergic patients and 10 nonatopic individuals. Results obtained showed that the recombinant allergens allowed in vivo allergy diagnosis in 52 of 54 of the grass pollen and in 35 of 36 of the birch pollen allergic patients. Positive skin reactions were observed almost exclusively in patients containing detectable allergen-specific IgE antibodies but not in the nonatopic group; however, sensitivity to a given allergen as measured by skin reactivity was weakly correlated with the levels of allergen-specific IgE. Our results demonstrate that recombinant allergens can be used for component-resolved skin test diagnosis (CRD) of the patients' allergen sensitization profile, whereas allergen extracts at best allow to identify allergen-containing sources. CRD may thus represent the basis for novel forms of patient-tailored immunotherapy.     

Results of atopy patch tests with house dust mites in adults with ''intrinsic'' and ''extrinsic'' atopic dermatitis

BACKGROUND: The most frequently employed diagnostic criteria of atopic dermatitis (AD) can be fulfilled in the absence of elevated total circulating IgE or specific IgE to food allergens or environmental aeroallergens and/or in the absence of personal or familial history of atopy as well. Therefore a distinction between 'extrinsic' or 'allergic' and 'intrinsic' or 'non-allergic' AD has been suggested. Recently, a patch test with environmental aeroallergens, named atopy patch test (APT), has been proposed for use in the study of AD. OBJECTIVE The aim of this study was to investigate the reactivity to APT in patients with 'extrinsic' and 'intrinsic' AD. PATIENTS, MATERIALS AND METHODS: Two groups of adult male subjects with AD were examined consecutively in our department (Department of Dermatology, Italian Navy Main Hospital, Taranto, Italy) andpatch tested with whole bodies of house dust mites (HDM) at a concentration of 20% in petrolatum (Dermatophagoides pteronyssinus 50%, D. farinae 50%). The groups included: (i) 95 patients affected by the adult clinical form of 'extrinsic' AD; (ii) 12 patients affected by the adult clinical form of 'intrinsic' AD; and (iii) a control group of 49 adult healthy male subjects with a negative anamnesis for eczema and atopy and negative skin prick test to aeroallergens/food allergens and/or normal level of total circulating IgE, also patch tested with the same allergen. The statistical differences were calculated by chi2 test and 95% confidence intervals (CI) were provided. RESULTS: The APT was positive in 47.4% (CI: 37-57%) of'extrinsic'AD, in 66.6% (CI: 41-93%) of'intrinsic' AD and in 12.2% (CI: 3-21%) of healthy subjects. The differences between the two AD subgroups and the control group were statistically significant (P < 0.001). CONCLUSIONS: APT positivity is more frequent in both 'extrinsic' and 'intrinsic' AD than in unaffected subjects. Other studies are needed to confirm our data and to explain why the APT is positive in the 'intrinsic' form.     

Correlation among skin prick test, total and specific IgE UniCAP tests in atopic patients from Zagreb, Croatia

The correlation of pollen allergens, Dermatophagoides pteronyssinus and animal dender was assessed during a two-year period. Results of skin prick test, total and specific IgE UniCAP tests were compared in atopic patients (AP) with the following diagnoses: atopic dermatitis, allergic rhinitis, allergic conjunctivitis, allergic bronchitis or asthma, allergic urticaria and angioedema. The study included total and specific IgE (in vitro) tests to allergen mixtures (grass, tree, weed) or to single allergens of Dermatophagoides pteronyssinus (Der p), cat and dog fur, feather, etc. Comparison of skin prick test with total and specific IgE UniCAP immunoassay was done in 173 patients, i.e. 107 female and 66 male atopic patients aged 9-76 years. Allergies were most commonly recorded in the 25-35 age group. Total IgE ranged from 8.63 kU/l to >4000 kU/l, with specific IgE ranging from class 1 to class 5. Skin prick test showed high correlation with specific IgE for grass and weed pollen in patients with repiratory allergy (50.28%). Good correlation among all three tests was quite frequently observed. The results suggest that the study should be continued using these three tests in further cases of atopic dermatitis.     

Airborne contact dermatitis due to Japanese cedar pollen

Contact dermatitis caused by airborne antigen is a well-recognized problem. Previously, airborne contact dermatitis after contact with Japanese cedar pollen [Japanese cedar pollen dermatitis (JCPD)] has been reported in Japan. However, there is still no diagnostic test to evaluate contact dermatitis due to Japanese cedar pollen. Skin tests with Japanese cedar pollen have been used to investigate these patients. A histological analysis was also conducted to clarify the mechanism of JCPD. We performed a scratch-patch test, scratch test and assays for total immunoglobulin E (IgE) and specific IgE in 13 patients suspected to have skin symptoms from Japanese cedar pollen, 5 patients with Japanese cedar pollinosis and 15 control normal subjects. All subjects were tested with Japanese cedar pollen allergen extract. A skin biopsy was performed from a Japanese cedar pollen-scratch-patch-test positive in patients with JCPD. The result after 48 hr of scratch-patch test was compared with the patient's history and the findings of corresponding scratch test and specific IgE. 100% of the 13 patients with JCPD showed a positive scratch-patch-test reaction to Japanese cedar pollen extract. However, 20% of the patients with the Japanese cedar pollinosis without any eruptions showed a positive scratch-patch-test reaction. The percentage of positive results for specific IgE and the scratch test did not differ substantially between Japanese cedar pollionosis patients with a history of chronic erythema after contact with Japanese cedar pollen and those without such a history. No side-effects were observed regarding the scratch-patch test. Control subjects showed 7% positive reaction. Histological examination showed that eczematous change (spongiosis, intracellular oedema and acanthosis), and infiltration of lymphocytes and eosinophils were all observed at the scratch-patch-test-positive sites. We therefore concluded that the use of the scratch-patch test with Japanese cedar pollen extract was useful for accurately diagnosing JCPD.     

Atopy patch test reactions to Malassezia allergens differentiate subgroups of atopic dermatitis patients

BACKGROUND: The yeast Malassezia is considered to be one of the factors that can contribute to atopic dermatitis (AD). OBJECTIVES: To investigate the reactivity to Malassezia allergens, measured as specific serum IgE, positive skin prick test and positive atopy patch test (APT), in adult patients with AD. METHODS: In total, 132 adult patients with AD, 14 with seborrhoeic dermatitis (SD) and 33 healthy controls were investigated for their reactions to M. sympodialis extract and three recombinant Malassezia allergens (rMal s 1, rMal s 5 and rMal s 6). RESULTS: Sixty-seven per cent of the AD patients, but only one of the SD patients and none of the healthy controls, showed a positive reaction to at least one of the Malassezia allergens (extract and/or recombinant allergens) in at least one of the tests. The levels of M. sympodialis-specific IgE in serum correlated with the total serum IgE levels. Elevated serum levels of M. sympodialis-specific IgE were found in 55% and positive APT reactions in 41% of the AD patients with head and neck dermatitis. A relatively high proportion of patients without head and neck dermatitis and patients with low total serum IgE levels had a positive APT for M. sympodialis, despite lower proportions of individuals with M. sympodialis-specific IgE among these groups of patients. CONCLUSIONS: These results support that Malassezia can play a role in eliciting and maintaining eczema in patients with AD. The addition of an APT to the test battery used in this study reveals a previously overlooked impact of Malassezia hypersensitivity in certain subgroups of AD patients.     

Reproducibility of food atopy patch tests over time in the general child population

Background  The atopy patch test (APT) is no longer an experimental method; it is increasingly being used as a standard diagnostic tool for the characterization of patients with aeroallergen- and food-triggered disorders. Some technical aspects of this test still remain to be answered. We aimed to study the reproducibility of this test over time in the general child population.
Methods  In a general population of 118 children, we investigated the reproducibility of duplicate APTs with four food allergens in their native form, which were repeated at set intervals from the first test: 7 days (group 1), 14 days (group 2), and 21 days (group 3).
Results  We observed very poor reproducibility on both sides of the back in all three studied subgroups. The reproducibility rates and Cohen's κ values did not improve when we did not consider the side of the back. There were no differences in the prevalence of atopy between the subjects with reproducible and nonreproducible APT results. All three groups studied showed no difference in the prevalence rates of atopy. There was no relationship between APT and skin prick test positivity for the same allergen. Questionnaire-derived data about previous food-related reactions did not help in the evaluation of the doubtful nonreproducible APT results with food allergens.
Conclusions  Our results show that the reproducibility of food APTs is poor and unsatisfactory over time, and there is an urgent need for the development of optimal, stable, and good-quality APT testing substances.     

Patch testing with egg represents a useful integration to diagnosis of egg allergy in children with atopic dermatitis

Our aim was to investigate atopy patch and skin prick test reactions to egg in 85 children with atopic dermatitis, and to evaluate their relevance by performing repeated open challenges with egg. Thirty-one percent of our patients showed an eczematous response to the challenge. Positive reactions to atopy patch and skin prick tests were recorded in 37% and 19%, respectively. Atopy patch test sensitivity proved significantly higher than that of skin prick test (79.6% vs. 46.2%), whereas specificity was lower (81.4% vs. 93.2%). Our data suggest that combined skin prick and patch testing improves screening for egg allergy in affected children, identifying 92% of those who were challenge positive among our patients.     

Radioimmunologic determination of total IgE and allergen-specific IgE-antibodies in diffuse neurodermitis]

Total IgE levels in sera of 165 patients with atopic dermatitis and 79 patients with dermatoses as well as normal control patients were determined by radioimmunoassay (Phadebas, Pharmacia). Although the mean value for patients with atopic dermatitis was found far above the mean value for normal controls, 38% of patients showed total IgE serum levels within the normal range. Highest IgE serum levels were observed in patients with the generalized form of the disease and in patients with asthma and allergic rhinitis. No direct correlation however, to severity of disease could be found. In a series of 50 patients prick tests were compared to total IgE serum levels and to levels of allergen specific antibodies determined by radioallergosorbent-test (RAST). Extracts of grass pollens and of animal dandruff were used. There was complete agreement between results of skin testing and RAST in at least 80%. While cross reactions were common with grass pollen extracts in RAST, there was no cross-over with animal dandruff. No correlation was found between titer of allergen specific antibody and severity of skin lesions. IgE specific antibody could be detected in 48% of patients with normal total IgE serum levels and in 82% of patients with elevated values.     

Contact allergy to aeroallergens in children with atopic dermatitis: comparison with allergic contact dermatitis

Immediate and delayed cutaneous hypersensitivity are believed to be implicated in the physiopathology atopic dermatitis (AD). The purpose of this study was to evaluate Type I and Type IV allergy to aeroallergens in children with AD. 59 children (mean age 5.2 years), presenting with AD according to Hanifin and Rajka's criteria, were skin tested (patch and corresponding prick tests) with common environmental aeroallergens and a restricted panel of the European standard series over a 1-year period. History and clinical data were carefully recorded using a standardized evaluation sheet: total and specific IgE serum levels were evaluated 17 of 59 patients (28.8%) had at least 1 positive patch test, 32 of 59 patients (54.2%) had at least 1 positive prick test. Corresponding patch and prick tests were observed in 8 out of 17 patients. 5 children with positive patch tests had negative prick tests. Irritant pustular reactions (2/59, i.e. 3%), "angry back" reactions (6/59, i.e. 10%) and doubtful reactions (3/59, i.e. 5%) were excluded from the positive group. Positive patch tests observed included, in decreasing order: D. pteronyssinus and D. farinæ (26.8%) garden trees (12.2%), plantain (9.8%), timothy grass, mugwort and damp area trees (4.9% each), and orchard grass (2.44%). 6 children with positive aeroallergen patch tests and 11 children with negative aeroallergen patch tests had at least 1 positive patch test to standard allergens. All children with an irritant reaction to aeroallergens had no reaction to standard patch tests. The relevance of aeroallergens in upgrading the severity of AD lesions has still to be explored by challenge studies and by long-term follow-up.     

Skin test results but not serology reflect immediate type respiratory sensitivity: a study performed with recombinant allergen molecules.

The diagnosis of type I allergy, an IgE-antibody-mediated hypersensitivity disease affecting more than 25% of the population, is based on the measurement of allergen-specific serum IgE levels and provocation testing. Whether the determination of allergen- specific serum IgE levels can replace in vivo provocation testing for allergy diagnosis is a controversial issue. We used purified recombinant timothy grass and birch pollen allergens to compare by skin prick and nasal provocation testing as well as by serology in vivo sensitivity with antibody-binding capacity in 24 pollen allergic patients and eight control individuals. Results from biologic tests were correlated with each other and with allergen-specific IgE and IgG1-4 levels. IgE-reactive allergens induced immediate skin and nasal reactions, but the intensity of the allergic tissue reactions was not correlated with either the levels of allergen-specific IgE or the levels of allergen-specific IgG antibodies. Less frequently detected allergens with low IgE-binding capacity were able to induce strong allergic reactions comparable to those caused by major allergens with high IgE-binding capacity. In contrast, skin test and nasal provocation results were significantly correlated (r = 0.63, p < 0.01). Our study thus demonstrates on a molecular level that skin testing provides a better reflection of immediate type respiratory sensitivity than serologic measurements. These results have implications for allergy diagnosis and, in particular, for the selection of relevant allergen components for specific immunotherapy.     

Die Bedeutung der Nahrungsmittelallergie bei Patienten mit atopischer Dermatitis

Besides other trigger factors food allergens have been shown to play a major role in the exacerbation and maintenance of eczematous lesions in patients with atopic dermatitis (AD), particularly in children. Food allergy may not only present as a flare up up of eczema in these patients, but also immediate type reactions and mixed reactions can be observed under food challenge tests.Whereas cow's milk hen's egg, wheat and soy have been identified as important triggers in infants, pollen related foods like nuts, fruit und vegetable have a greater impact in adolescents and adult Food specific T cells have been identified as effector cells in food responsible eczema and food specific T cell clones could be generated from lesional skin of patients who reacted with a worsening of their AD upon oral challenge tests. Due to the poor reliability of in-vitro (RAST) and skin tests (skin prick test (SPT), atopy patch test (APT)) the double blind placebo controlled food challenge (DBPCFC) is regarded as the gold standard in the diagnostic work-up of food allergy. Once a food allergy has been diagnosed, a specific elimination diet represents the first line therapy, which has to consider the supplementation of essential nutrients.