Allergy testing

Percutaneous and intradermal skin tests and laboratory assays of specific IgE antibodies may be useful in selected cases of allergy management. Percutaneous testing kits are available from various manufacturers. A number of common allergens are available in standardized preparations. Positive and negative skin controls are important in establishing reliable results. Antihistamine medications can interfere with skin testing and should be stopped beforehand. Serious reactions to skin testing are rare. Establishing the sensitivity and specificity of percutaneous testing is difficult because there is no widely accepted gold standard for defining a true allergic reaction. Intradermal testing is more sensitive than percutaneous methods but much less specific. Its use is restricted to testing for allergy to insect stings or penicillin. In cases where skin testing is not available or desirable, laboratory assays for IgE antibodies to specific allergens may be used. These assays are generally less sensitive than skin testing methods. Selected patients with allergic rhinitis or asthma that is not controlled with standard therapy may benefit from allergy testing, especially when it can target allergen avoidance measures or guide immunotherapy.     

Immediate-type hypersensitivity to reactive dyes

Reactive dyes have gained extensive use in recent years. This paper reports four cases of immediate-type occupational allergy to these compounds. All the patients had had symptoms of asthma and allergic rhinitis, and had been weighing dyes for a minimum of 2 years. The skin prick tests were positive, and nasal and bronchial provocation challenges also produced positive immediate reactions. A high serum titre of specific IgE could be demonstrated for at least one dyd by the radioallergosorbent test. The identification of specific IgE shows that the mechanism of the hypersensitivity is immunological, reactive dyes acting probably as haptens.     

成都地区变应性鼻炎患者皮肤点刺结果分析

目的：调查成都地区变应性鼻炎患者主要变应原的分布特点。方法：采用标准化变应原对286例经四川大学华西医院耳鼻咽喉头颈外科医师检查怀疑患有变应性鼻炎的门诊患者进行皮肤点刺试验。结果：皮肤点刺试验阳性率80．8％,前5位的变应原分别为屋尘螨（66．4％）、粉尘螨（65．0％）、杂草（36．4％）、霉菌Ⅱ（25．2％）、霉菌Ⅰ（21．3％）。不同性别之间变应原分布无差异,儿童对粉尘螨和屋尘螨的敏感程度明显高于成人。绝大多数变应性鼻炎患者对多个变应原皮试反应阳性。结论：成都地区变应原的分布特点与气候的特殊性一致,尘螨是最重要的变应原,应重视对尘螨的特异性免疫治疗的开展。     

Skin prick testing in general practice: a pilot study

Allergy skin prick testing is regarded as a routine diagnostic procedure in hospital settings, but its role in general practice is not yet defined. Our aim was to explore the ways in which skin prick testing might facilitate the work of general practice nurses engaged in asthma patient care. A structured questionnaire was completed by 18 practice nurses before and again after administering allergy skin tests to four common aeroallergens (dust mite, grass pollen, cat and dog danders) to 319 consecutive attenders with known or suspected asthma. Nurses' decisions about whether or not to give allergen avoidance advice were reversed after skin testing in 63 (22%) cases for dust mite, 67 (23%) cases for grass pollen, 38 (13%) cases for cat fur and 49 (17%) cases for dog hair. Had allergen avoidance interventions been targeted only at patients with both a positive skin test and a positive clinical history, the number of planned interventions would have declined from 305 before skin testing to 142 after. The findings suggest that allergy skin prick testing was feasible and acceptable in general practice, and that one role may be to reduce the number of allergen avoidance interventions offered to patients unlikely to benefit.     

Der f2重组蛋白用于变应性鼻炎患者血清ELISA检测

目的：以重组表达的野生型粉尘螨变应原蛋白质第2组（Derf2）分作为固相包被抗原,建立间接酶联免疫吸附试验（ELISA）法,检测粉尘螨致敏的持续性变应性鼻炎患者血清中的特异性IgE浓度。方法：经过皮肤点刺试验证明的24例粉尘螨反应阳性血清和2例阴性血清作为IgE血清样本。以粉尘螨变应原蛋白质第2组分固相包被酶标板,辣根过氧化物酶（HRP）标记的抗人IgE单抗作为第2抗体组成测试系统分析特异性IgE。结果：间接ELISA系统检测灵敏度为0.73U.mL-1。在4.0U.mL-1、12.0U.mL-1、22.0U.mL-1浓度,批内重复性和批间重复性分别为9.5%,7%,6.1%和12.8%,9.1%,7.2%。24例皮试阳性患者血清经ELISA分析,有22例阳性。结论：以粉尘螨变应原蛋白质第2组分作为固相包被抗原的间接ELISA法可用来对患者血清sIgE作定量或定性分析,有助于持续性变应性鼻炎的实验诊断。     

变应原皮肤点刺试验750例的结果分析及护理体会

目的探讨变应原皮肤试验结果对临床的指导意义，并总结试验过程中的护理配合。方法对2007年3—9月750例疑诊为变应性鼻炎患者做变应原皮肤点刺试验，统计分析变应原皮肤试验的结果，并制定严密的护理和急救措施。结果750例受检者中皮试阳性者680例（90．67％）、阴性者70例（9．33％）；室内变应原主要种类为屋尘螨614例（90．3％）、粉尘螨594例（87．4％）、热带螨300例（44．1％），而植物性变应原为艾草38例（5．6％）、豚草34例（5．0％）。所有皮肤试验者均未发生严重全身过敏反应。结论变应原皮肤试验是诊断变应性鼻炎的重要依据，可为特异性免疫治疗提供参考；试验过程中应配合健康教育和心理护理，并加强护理观察。     

福建泉州地区2137例过敏性疾病患者变应原皮肤点刺试验结果分析

目的分析福建泉州地区过敏性疾病患者变应原皮肤点刺试验结果,为过敏性疾病的诊治及预防提供依据。方法选择2015-2018年在该院就诊的过敏性疾病患者,采用变应原皮肤点刺试验对29种标准变应原(3种混合变应原和26种单一变应原)进行测试,以组胺液为阳性对照,生理盐水为阴性对照。结果共有2137例符合条件的过敏性疾病患者纳入研究,患者中位年龄为28岁,男、女的变应原阳性率比较,差异无统计学意义(P>0.05)。过敏性疾病诊断主要为过敏性鼻炎、荨麻疹和过敏性咳嗽,发病高峰为每年7-8月。变应原测试结果显示,变应原种类丰富,皮肤点刺试验总阳性率为76.18%,变应原种类以屋尘螨、粉尘螨和蟑螂为主,阳性率明显高于其他变应原(P<0.05)。单一变应原阳性反应者较少,73.53%(1197/1628)的患者对3种及以上变应原反应阳性。致敏以轻度反应为主的患者中,变应原种类最多,3~30岁患者变应原阳性反应强度较高(P<0.05)。结论该研究揭示的变应原致敏特点将有助于该地区过敏性疾病的预防、诊断和管理。     

The correlation between skin tests, bronchial provocation tests and the serum level of IgE specific for common allergens in patients with asthma.

Cutaneous and bronchial immediate allergic reactivity and the serum level of IgE specific for each of four common inhalant allergens were determined for 153 asthmatic patients. Positive bronchial reactivity to an extract was not detected in any of the patients with a negative prick test reaction to that extract but did occur in 9% of the patients in whom the serum tests results for IgE specific to that allergen fell within the range regarded as negative. Highly significant correlation coefficients between the degree of bronchial and cutaneous allergic reactivity to the allergen extracts were found and these were slightly but significantly less than the correlation between the serum level of allergen specific IgE and the degree of bronchial allergic reactivity to the allergen extracts. These findings indicate that the results both of prick testing with appropriate extracts and estimation of the serum level of allergen specific IgE can be used to predict not only the presence of detectable bronchial reactivity to inhalant allergens but also the degree of this reactivity. However, for the routine investigation of asthmatic patients measurement of the serum level of allergen specific. IgE would appear to have little advantage over properly performed prick tests.     

Clinical significance of specific IgE determination on nasal secretion

The clinical use of RAST on the nasal secretions was investigated in seventeen atopic patients, with asthma or rhinitis, who had shown at a first diagnostic screening, some difficulties in the identification of the responsible allergen(s). The results of the skin tests, of the RAST on the serum and on the nasal secretions and of the specific provocation test (bronchial or nasal) were compared. In some cases the basophil degranulation test was performed. The results of the RAST on the nasal secretions were in perfect agreement with the provocation test. The skin tests and the RAST on the serum showed many discrepancies, particularly for Dermatophagoides, epidermal derivatives of cat and dog and moulds, and less frequently for Graminaceae and other pollens. It is concluded that RAST analysis on nasal secretions is useful in clinical diagnosis of allergy especially for Dermatophagoides, epidermal derivatives and moulds. Most false positive results were observed with the RAST on serum; in fifteen cases it was positive, while all the other tests, basophil degranulation test included, were negative. The data suggest that IgE may have a low affinity for basophil receptors.     

Flow cytometric analysis of in vitro activated basophils, specific IgE and skin tests in the diagnosis of pollen-associated food allergy

BACKGROUND: Specific immunoglobulin E (IgE) and commercially available skin prick tests have been demonstrated to be unreliable methods to diagnose pollen-associated food allergy. To evaluate the predictive value of the basophil activation test (BAT) in pollen-associated food allergy, the apple-mediated oral allergy syndrome (OAS) in patients with birch pollinosis was chosen as a representative model. METHODS: Patients with birch pollen allergy and a history of apple-mediated OAS (OAS(+), n = 29), patients with birch allergic without OAS (OAS(-), n = 22), and healthy controls (HC, n = 10) without birch pollen allergy and OAS were included. Apple IgE was quantified by the CAP FEIA method. Skin prick tests were performed with a Jonagold apple extract. Flow cytometric analysis of basophils activated with the same Jonagold extract was based on double staining with anti-IgE/anti-CD63 monoclonal antibodies. RESULTS: Comparison between OAS(+) subjects and HC showed sensitivities and specificities of 96% and 100% for apple IgE and 88% and 100% for the apple skin prick test, respectively. For the BAT, sensitivity and specificity were 100%. In contrast, when nonresponders on the BAT were considered, sensitivity decreased to 90%. In a separate analysis between OAS(+) and OAS(-) subjects, specificities decreased to 30% for apple IgE and to 80% for the apple skin test, respectively. The BAT reached a sensitivity of 88% and a specificity of 75%. CONCLUSION: Flow cytometry-assisted quantification of in vitro basophil activation seems to be a reliable instrument in the diagnosis of this model of pollen-associated food allergy. In addition, this study reemphasizes that the specificity of diagnostic allergy tests decreases considerably when, apart from HC, control individuals with cross-reactive antibodies are included.     

Different allergenic activity of grass pollen allergens revealed by skin testing

Background Grass pollen is one of the most important allergen sources. The aim of this study was to compare the in vivo allergenic activity of two recently characterized major grass pollen allergens, Phl p 4 and Phl p 13, with three established major grass pollen allergens, Phl p 1, Phl p 2 and Phl p 5 as a basis for the formulation of a grass pollen allergy vaccine based on purified allergens. Material and methods Eighty‐two grass pollen allergic patients were skin prick tested with serial dilutions of approximately equimolar concentrations of the purified allergens in a double‐blind study. Results Phl p 4 and Phl p 13 were identified as major grass pollen allergens according to IgE binding frequency (Phl p 4: 85%; Phl p 13: 56%), but exhibited a five to nine‐fold lower allergenic skin reactivity compared to Phl p 1, Phl p 2 or Phl p 5. Conclusion Our results indicate that Phl p 4 and Phl p 13 are not essential components for a therapeutic grass pollen vaccine and underpin the importance of evaluating the in vivo allergenic activity of individual allergens for the formulation of therapeutic vaccines based on purified allergens.     

A new Soviet allergen made from bee venom for the specific diagnosis of allergic reactions to bee stings]

Overall 46 patients with allergic reactions to bee stings were examined. As a result of making skin prick, scarification and intracutaneous tests with an allergen from bee venom, allergy to bee stings was revealed in all the 46 patients, whereas only 37 patients responded to an allergen from the bee body. Specific IgE-antibodies using RAST were detected in 29 out of 31 patients. All the 29 patients had positive skin tests with an allergen from bee venom and only 22 with an allergen from the bee body. Specific histamine release was detected in all 13 patients examined by means of the indicated test. 100% coincidence was recorded with the results of intracutaneous tests with an allergen from bee venom. Only 11 out of the 13 patients had positive intracutaneous tests with an allergen from the bee body. Thus, the new Soviet allergen obtained from bee venom is effective in the diagnosis of allergy in response to bee stings.     

Allergen-induced hyperreactivity is not a feature of dermal immediate allergic reactions--in contrast to reactions of airways mucosa

Allergen challenges of airway mucosa are commonly followed by an increased sensitivity to rechallenge with allergen. In the lower airways this phenomenon has been associated with the late phase of allergic airway reactions, which in turn has been suggested as a link between anaphylaxis and continuous allergic airway disease. The aim of the present investigation was to explore further the phenomenon of allergen-induced hyperreactivity and to see whether it was possible to induce such a reaction in the skin. Twenty-six patients with seasonal allergic rhinitis due to birch and/or grass pollens were studied in the pollen-free winter months. Nine of these patients had previously demonstrated an increased reactivity following allergen challenge in the nose, and nine of the patients had cutaneous allergen-induced late-phase reactions to the allergen tested. Skin-prick tests were performed with pollen allergen, histamine, and a negative control. The areas of the weal-and-flare reactions were measured 15 min after the tests were set. Any late-phase reactions were recorded 6 hr after the skin challenge. The subjects were re-tested with allergen and histamine 24 hr after the initial prick test within the area of the corresponding weal from the previous day. In contrast to previous challenges of human airway mucosa, where the same time interval was used, we found no increased responsiveness to rechallenge as compared with the initial allergen challenge. This was true, even if only the subgroups with previously demonstrated nasal allergen-induced hyperreactivity, or cutaneous late-phase reaction were evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diagnosing and managing food allergy in children

The prevalence of food allergy in children in the UK is now around 5%. The number of children put on restricted diets by their parents because of presumed allergy is likely to be much higher. Accurate diagnosis of food allergy is essential in order to ensure that the correct foods are carefully avoided while safe foods are not excluded unnecessarily. IgE-mediated (immediate type) reactions are the result of mast cell degranulation leading to histamine release. The typical signs of lip swelling, urticaria and possible progression to respiratory compromise (anaphylaxis) are usually clearly described, occurring within minutes of exposure to the food. Non IgE-mediated (delayed type) responses tend to start 2-6 hours, occasionally longer, after exposure and cause less specific signs/symptoms, less obviously allergic in origin. Where an immediate type allergic reaction is suspected on clinical history, allergy testing should be performed to confirm the diagnosis. This could involve either skin prick testing or specific IgE blood tests. Results must be interpreted in the context of the clinical history. The mainstay of management is allergen avoidance. The child and carers also need to know how to recognise and treat any future allergic reactions. There should be a written emergency plan in place. The plan should include advice to take a fast-acting antihistamine if any accidental exposure and reactions occur. Where there is a history of anaphylactic reaction or ongoing asthma, adrenaline auto-injectors should be prescribed as these are the major risk factors for future severe reactions. Non IgE-mediated food allergy is most common in early infancy. The diagnosis of non IgE-mediated food allergy relies on a two-stage process: strict exclusion of suspected allergen(s), only one at a time; re-challenge with suspected allergen(s), one at a time, to see if symptoms recur.     

The variability of skin test hypersensitivity reactions in cystic fibrosis and asthma

Cystic fibrosis (CF) children had a greater variability of skin prick test response compared with asthmatic children, when the tests were performed on two occasions. This suggests that there is a different cause for the allergy in the two groups, perhaps because the asthmatics have a transient period of susceptibility to sensitization in infancy and the CF children a persistent vulnerability. Amongst the asthmatic children, clinical improvement was associated with loss of some skin prick test reactions, and clinical deterioration with an increase in the number of positive reactions. Thus continuing allergic reactions may maintain a mucosal defect, resulting in a persistence of susceptibility to allergen sensitization, and control of the reactions may re-establish normal mucosal defence mechanisms.     

国产屋尘螨皮肤点刺诊断试剂盒在诊断屋尘螨引起的变应性鼻炎中的应用价值

目的探讨屋尘螨皮肤点刺诊断试剂盒在诊断屋尘螨引起的变应性鼻炎中的应用价值。方法采用平行分组的研究方法和变应性鼻炎的诊断标准,选择屋尘螨阳性、阴性受试者各150例,采用屋尘螨皮肤点刺诊断试剂盒对受试者进行点刺试验,根据点刺液与阳性对照液产生丘疹面积的比值来判断受试者对屋尘螨的过敏程度,进而评估该试剂盒的敏感度和特异度。结果该试剂盒ROC的曲线下面积为0．947（0．90～0．98）,敏感度为91．4％,特异度为94．4％。阳性预测值在80％以上,除个别情况外,阴性预测值也在70％以上。在采用该试剂盒进行皮肤点刺试验的过程中,受试者未发生与点刺试验相关的全身不良反应。结论屋尘螨皮肤点刺诊断试剂盒具有安全、高敏感度、高特异度的特点,是辅助诊断由屋尘螨引起的变应性鼻炎等过敏性疾病的一种有效手段,也为特异性免疫治疗提供了可靠的客观依据。     

儿童过敏原皮肤点刺试验53例分析

目的观察部分过敏性疾病儿童的过敏原皮肤点刺试验结果。方法对支气管哮喘、过敏性鼻炎及湿疹/荨麻疹3组儿童行皮肤过敏原点刺试验,试剂为北京协和医院诊断试剂厂生产吸入组与食物组共40种过敏原试剂。结果（1）支气管哮喘儿童随年龄增大,皮肤阳性率呈增高趋势,而湿疹/荨麻疹组不明显。（2）常见过敏原吸入组为屋尘（15.1%）、尘螨（28.3%）、蟑螂（17.0%）、家蝇（20.8%）等;食物组为螃蟹（9.4%）、海虾（7.5%）、鲤鱼（7.5%）等。近年蟑螂及家蝇过敏原阳性率增高。（3）哮喘儿童皮肤试验阳性率54.5%,阴性率45.5%,其致病原（变应原）有可能与病毒引起的气道变应性炎症有关。结论（1）哮喘儿童过敏原阳性率随年龄增长而增高;（2）过敏性疾病儿童常见过敏原主要为屋尘、尘螨、蟑螂及家蝇等;（3）哮喘儿童除常见过敏原引起外,推测还与病毒感染有关;（4）过敏性疾病可针对过敏原进行有关防治。     

标准化皮试与特异性IgE测定在检测特异性过敏原中的比较

目的：比较标准化皮试和特异性IgE测定对过敏性哮喘患检测特异性过敏原的作用和意义。方法：对52例哮喘患分别作以下检测；采用国际标准化的Allergopharma过敏原皮试液（共12种）作点刺试验；采用UniCAP过敏原检测系统作混合吸入物过敏筛选试验（Phadiatop试验）。结果：52例哮喘患中标准化皮试阳性45例（占86.5%)。其中粉尘螨阳性42例（占93.3%)。52例哮喘患中Phadiatop试验阳性47例（90.4%)。其中44例（93.6%)标准化皮试同时为阳性；5例Phadiatop阴性中4例皮试呈阴性，标准化皮试与Phadiatop试验的总符合率为92.3%(48/52)。结论：采用国际标准化的皮试液作点刺试验同时辅以Phadiatop试验阳性或阴性对照判断结果。可作为吸入性过敏原特异性诊断较为可靠的标准化手段。     

Value of the case history in the diagnosis of allergic state and the detection of allergens

Detailed histories taken in eighty-one patients suffering from perennial asthma and rhinitis were analysed independently by three trained allergists and their conclusions were compared to the results of three tests: (1) concentration of total serum IgE; (2) skin tests and (3) radioallergosorbent test (RAST). In eleven patients (14%), the three investigators disagreed when estimating the allergic nature of the symptoms. Ten out of forty-four patients (23%), unanimously predicted not to be allergic, had high levels of total serum IgE and skin tests and RAST clearly positive for one or more allergens. The allergists suspected 47% of the allergens detected by skin tests and 55% of those detected by RAST. The case history was the test which most often gave information at odds with that suggested by the other three tests. Our study indicates therefore that a case history not even suggestive of allergy should be complemented by additional tests.