婴幼儿鸡蛋与牛奶过敏食物皮肤点刺试验的诊断价值

目的 通过对皮肤点刺试验疹团平均直径与开放性食物激发试验的相关性研究,获得有确诊食物过敏价值的皮肤点刺试验界值点,为简化临床诊断程序提供依据.方法 采用前瞻性研究,选择重庆医科大学附属儿童医院儿保科可疑食物过敏儿童173名,均进行皮肤点刺试验及开放性食物激发试验.测量并记录皮肤点刺试验疹团平均直径,通过开放性食物激发试验确诊食物过敏患儿.采用SPSS 13.0软件包进行统计学处理.将开放性食物激发试验作为诊断的金标准,通过四格表计算疹团平均直径的敏感度、特异度、阳性预测值及阴性预测值.通过受试者工作特征曲线及曲线下面积对疹团平均直径诊断价值进行评价;同时获取具有100%诊断价值的平均直径界值点.结果 173名婴幼儿年龄范围1～24个月,平均(9.39±5.67)个月共进行271次食物激发试验(其中阳性结果123次),99例婴幼儿被确诊为食物过敏.食物激发试验诱发症状主要表现为皮肤症状(87.0%),其次是胃肠道症状(9.8%).蛋白、蛋黄、牛奶皮肤点刺试验的受试者工作特征曲线的曲线下面积分别为0.794、0.804及0.904.当皮肤点刺试验疹团平均直径≥3 mm时,敏感度在71%～87%之间,特异度在31%～57%之间.当蛋白、蛋黄、牛奶皮肤点剌试验疹团平均直径分别≥8.5、5.5、5.5 mm时,皮肤点刺试验对食物过敏的诊断准确率可达100%.结论 皮肤点刺试验疹团平均直径对食物过敏的临床诊断准确性较好,通过其100%诊断界值点,可避免部分可疑食物过敏患儿进行食物激发试验.

Abstract：

Objective Mean diameter is the most common used parameter for wheal response assessment after skin prick test.This study aimed to investigate the diagnostic capacity of mean diameter according to the outcome of oral food challenge, and to determine the cut-off points that could render food challenges unnecessary.Method Data of 173 children referred to the Division of Primary Child Health Care for the evaluation of suspected food allergy were prospectively studied.All children underwent skin prick test and open food challenge to the relevant food(s) in clinic.The mean wheal diameter of skin prick test was measured, and open food challenge was performed to confirm food allergy. The SPSS software package version 13.0 for windows ( SPSS, Chicago, IL,USA) was used for all statistical analysis.Open food challenge was taken as the gold standard for diagnosis.Diagnostic capacity of skin prick test, including the sensitivity, specificity, positive predictive value, negative predictive value, was calculated by cross-table.In addition, receiver operating characteristic curve ( ROC ) was plotted and area under the curve ( AUC ) was calculated to quantify the accuracy of the parameter.Result For the 173 children,271 open food challenges were performed with egg white, egg yolk and cow's milk, In which 123 were positive, 99 children were diagnosed as food allergy.Cutanuous symptoms ( 87.0% ) were most common, followed by gastrointestinal symptoms (9.8% ).The AUC of mean diameter was 0.794 for egg white, 0.804 for egg yolk and 0.904 for cow's milk.The sensitivity of skin prick test with a cut-off value of ≥3 mm was ranged from 71% to 87%,while the specificity was between 31% and 57%.The authors also defined food specific skin prick test mean diameters that were 100% diagnostic for allergy to egg white ( ≥8.5 mm), egg yolk ( ≥5.5 mm), cow's milk ( ≥5.5 mm).Conclusion Predictive decision points for a positive outcome of food challenges can be calculated for egg and cow's milk using mean diameter.It may help to simplify the diagnostic procedure of food allergy.     

Skin prick test predictive value on the outcome of a first known egg exposure in milk-allergic children

Children with milk allergy have higher incidence of other food allergies, especially egg allergy. The objective of this study was to ascertain the accuracy of the prick test in children with IgE-mediated milk allergy for diagnosing egg allergy. Children under the age of 1 yr who came consecutively to Allergy Department 2003–05, and were diagnosed with IgE-mediated milk allergy were selected for this study. Egg introduction was completely avoided until the age of 14 months when clinical history, skin prick tests (SPT), specific-IgE antibodies determination and egg challenge test were performed. One hundred and four milk-allergic children were included. At least one positive prick test to any egg allergen was found in 65 out of the 104 (62.5%). Thirty-eight (36.5%) were allergic to egg proteins as well. Prick tests with egg white and ovomucoid (OVM) had the best diagnostic performances showing the largest areas under the receiver operating characteristic curve. The optimal diagnosis cut-off point was 6 mm for egg white and 5 mm for OVM. The positive likelihood ratios for these cut-off points were: 2.95 (95% CI: 1.74–4.99) for egg white prick test, and 20 (95% CI: 2.9–143.7) for OVM prick test. Children with specific IgE-mediated cow's milk allergy must be closely followed as a risk group for egg allergy. Early diagnosis is necessary and the SPT has shown itself to be a very useful tool for diagnosing immediate IgE reactions to egg on first known exposure.     

Allergenicity of milk protein hydrolysate formulae in children with cow's milk allergy

Cow's milk protein hydrolysate formulae have been developed to lower or eliminate the allergenicity of cow's milk proteins, and to reduce the antigenic load and the risk of sensitization. Cross-reactivity between different hydrolysate formulae and cow's milk proteins has been demonstrated. We have studied 20 children (median age 31 months, range 15–76 months) with a history of IgE-mediated cow's milk allergy. All the children had immediate allergic respiratory and/or cutaneous and/or gastro-intestinal reactions to cow's milk ingestion. In addition, the children had positive prick skin tests and positive RAST to cow's milk. Prick skin test, RAST, and double-blind placebo controlled food challenges were performed with three different hydrolysate formulae: a casein hydrolysate formula and two whey formulae, one partially and one extensively hydrolyzed. All 20 children had immediate allergic reactions after the challenge test with cow's milk. Only 2/20 children had a positive challenge test with a casein hydrolysate formula (Alimentum): one developed asthma and one urticaria. Two of the 15 children challenged with an extensively hydrolysed whey formula (Profylac) developed perioral erythema. Nine out of 20 children had a positive challenge test with a partially hydrolysed whey formula (Nidina H.A.): four developed asthma, three urticaria and two lip oedema. All children had positive prick skin tests to cow's milk proteins (casein and/or lactalbumin); 9 to Nidina H.A.; 3 to Profylac, and 3 to Alimentum. Specific IgE antibodies to cow's milk were present in all children; in 13 to Nidina H.A., in 4 to Profylac, and in 3 to Alimentum.     

Cow's milk allergic children can present sensitisation to probiotics

Aim: To evaluate sensitivity to different probiotics in children with cow's milk allergy.
Methods: Eighty-five patients (age range: 4 months –12 years) presenting atopic dermatitis (AD) were enrolled. Skin prick test (SPT) responses to three different probiotics preparations (Fiorilac®, Dicoflor® and Reuterin®) were evaluated in addition to relevant food allergens.
Results: Thirty-nine patients out of 85 (45.8%) had a positive skin response to prick test for cow's milk (3 with reaction <3 mm). Of the thirty-six patients with a cow's milk weal reaction >3 mm, twenty-eight (77.8%) had a skin response to Fiorilac®, four patients (11%) to Dicoflor® and four (11%) to Reuterin®. The proportion of SPT reaction to all the investigated probiotics preparations was significantly lower than cow's milk (r = 9.406; p = 0.002). A significantly higher sensitization was observed for Fiorilac® versus Dicoflor® (r = 30.916; p < 0.001) and versus Reuterin® (r = 34.133; p < 0.001).
Conclusion: Probiotic use in patients with cow's milk allergy has to be limited to products that do not contain milk. This should be clearly reported in the label. In selected patients, it is advisable to perform a screening SPT with the product to evaluate its potential contamination with milk.     

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??Abstract??Objective To investigate the diagnostic value of mean diameter of SPT in food allergic infants. Methods Totally 91 infants suspected with food allergy ??median age 7.35±2.94 months?? were selected??and all patients received family history inquiry??skin prick test and open food challenge.The mean diameter of SPT was measured??and OFC was performed to confirm food allergy.Diagnostic value of skin prick test, including the sensitivity and specificity, was calculated.In addition??receiver operating characteristic curve??ROC?? was plotted and area under the curve??AUC??was calculated to quantify the accuracy of the parameter.The SPSS software package version 13.0 for windows was used for all statistical analysis. Results A total of 128 babies received food challenge test?? in which there were 109 times of OFC positive and 19 times negative??totally 79 infants were diagnosed with FA.The induced symptoms of food challenge test included skin symptoms??70.6%??, gastrointestinal symptoms??20.2%??, rest with crying?? coughing?? rubbing eyes??etc.??9.2%??.When the rash MD was ≥3 mm??the sensitivity of SPT diagnosis milk??egg white and protein allergy was 19%??60.6% and 60.5% respectively??the area under ROC curve of rash MD in the milk??egg white??protein was 0.718??0.604 and 0.716 respectively?? the rates of three food SPT test results complying with the OFC were 44.4%??53.7% and 65.9%??the rates being 62.5%?? 58.3% and 31.3% in positive family history??when family history was negative??the area under the ROC curve of rash MD was 0.793. In the cases with positive family history??the area of ROC curve was 0.533.When rash MD of milk??egg white and protein was ≥2.2??5.0??4.7 mm or the rash MD was ≥3.25mm in children with a negative family history??SPT FA diagnostic specificity could be up to 100%. Conclusion SPT has some value in the diagnosis of FA. By finding the critical value of SPT FA and comprehensive analysis of family history??doctors can improve the diagnostic rate of FA. SPT can prevent some suspicious FA infants from food challenge test. It is very important to obtain rapid clinical diagnosis and to reduce the risk and burden to their families.     

The diagnostic value of skin prick testing in children with food allergy

The diagnostic accuracy of the skin prick test (SPT) in food allergy is controversial. We have developed diagnostic cut-off levels for SPT in children with allergy to cow milk, egg and peanut. Based on 555 open food challenges in 467 children (median age 3.0 yr) we defined food-specific SPT weal diameters that were '100% diagnostic' for allergy to cow milk (>or=8 mm), egg (>or=7 mm) and peanut (>or=8 mm). In children < 2 yr of age, the corresponding weal diameters were >or=6 mm, >or=5 mm and >or=4 mm, respectively. These SPT cut-off levels were prospectively validated in 90 consecutive children 相似文献   

Anaphylaxis to sheep's milk cheese in a child unaffected by cow's milk protein allergy

A 5-year-old atopic boy unaffected by cow's milk protein allergy experienced several anaphylactic reactions after eating food containing “pecorino” cheese made from sheep's milk. Prick-prick tests were strongly positive to sheep's buttermilk curd and `pecorino' sheep's cheese. Skin prick tests to fresh sheep's milk and to goat's milk were also positive, whereas they were negative to all cow's milk proteins, to whole pasteurized cow's milk and to cheese made from cow's milk. Specific IgE antibodies were negative to all cow's milk proteins. Conclusion Sheep's milk and cheese derived from sheep's milk may cause severe allergic reactions in children affected and, as we report, in children not affected by cow's milk protein allergy. Received: 14 January 1997 and in revised form: 20 June 1997 / Accepted: 8 July 1997     

The predictive value of skin prick testing for challenge-proven food allergy: a systematic review

Immunoglobulin E-mediated (IgE) food allergy affects 6-8% of children, and the prevalence is believed to be increasing. The gold standard of food allergy diagnosis is oral food challenges (OFCs); however, they are resource-consuming and potentially dangerous. Skin prick tests (SPTs) are able to detect the presence of allergen-specific IgE antibodies (sensitization), but they have low specificity for clinically significant food allergy. To reduce the need for OFCs, it has been suggested that children forgo an OFC if their SPT wheal size exceeds a cutoff that has a high predictability for food allergy. Although data for these studies are almost always gathered from high-risk populations, the 95% positive predictive values (PPVs) vary substantially between studies. SPT thresholds with a high probability of food allergy generated from these studies may not be generalizable to other populations, because of highly selective samples and variability in participant's age, test allergens, and food challenge protocol. Standardization of SPT devices and allergens, OFC protocols including standardized cessation criteria, and population-based samples would all help to improve generalizability of PPVs of SPTs.     

The predictive value of specific immunoglobulin E levels for the first diagnosis of cow''s milk allergy. A critical analysis of pediatric literature

Investigators have tried to identify a level of seric specific immunoglobulin E (IgE) that had a sufficient predictive value to diagnose a food allergy without having will resort to the food challenge. To search in literature, all the studies that have estimated the possibility to identify a level of seric specific cow milk IgE with a positive predictive value (PPV) of 95% for the first diagnosis of cow's milk allergy (CMA) in pediatric age. We have identified six studies, nearly all studies suffer from relevant methodological bias. Proposed cut-off are all different. The studied pediatric populations were highly selected. Also neglecting the methodological bias of the studies and the great difference of value between the proposed cut-off, it always remains to consider that the pre-test probability of having a CMA between the children enrolled in the six studies included in this review is particularly high. The likelihood ratio helps to transfer the results of a study on a diagnostic test just to our population, and it is more realistic rather than to entrust itself to the PPV or the negative predictive value, that are much influenced from the prevalence of the disease in the studied population.     

Combining skin prick, immediate skin application and specific-IgE testing in the diagnosis of peanut allergy in children

Previous studies have suggested various diagnostic cut-offs of allergy tests for the diagnosis of clinical peanut allergy in children. There are few data relating to the use of combinations of these tests in children. We aimed to determine the validity of previously reported diagnostic cut-off levels of peanut allergen skin tests and peanut specific-immunoglobulin (Ig) E, as well as the usefulness of combinations of these, for predicting clinical peanut allergy in our Allergy Clinic. Children attending the Allergy Clinic with a positive peanut skin prick test (SPT; n = 84) were included in the study. Immediate skin application food tests (I-SAFT) using 1 g of peanut butter (positive if any wheals were detected at 15 min), peanut specific-IgE levels and open-label peanut food challenges were performed. Fifty-two of 85 peanut challenges were positive. Skin prick test specificity was 67% at >or=8 mm and 100% at >or=15 mm. The I-SAFT was 82% specific. A peanut specific-IgE level of 0.37 kU/l was 98% sensitive but 33% specific. A level of 10 kU/l was 100% specific. Combinations of a SPT of >or=8 mm with a positive I-SAFT and a peanut specific-IgE >or=0.37 kU/l were 88% specific with a sensitivity of 38%. Using challenge outcomes as the standard, available in vitro and in vivo diagnostic tests for peanut allergy have poor sensitivity and specificity and combining them does not significantly improve their clinical usefulness. Previously described diagnostic cut-off levels do not have general applicability. Allergy practitioners may need to interpret results of allergy tests in the context of their own practices.     

Status of children with cow's milk allergy in infancy by 10 years of age

To assess the development of milk protein tolerance and atopic diseases in children diagnosed for cow's milk allergy (CMA) in infancy, we conducted re-examinations of 56 CMA subjects at the age of 10 y using 204 age-matched controls. The children underwent clinical examinations and skin prick tests (SPT), and their IgE-specific antibodies to milk and five other food allergens were determined. By the age of 10 y, all but four subjects had become tolerant to at least small amounts of milk protein. However, gastrointestinal symptoms relating to more abundant milk consumption were reported by 45% of the study subjects and 15% of the controls (p < 0.001). The incidence figures for asthma, allergic rhinitis and dermatitis, as well as the occurrence of recurrent otitis, were three to four times higher than in the controls. Positive SPTs were seen in two-thirds of the subjects, the figure being highest (83%) in those with dermatitis onset CMA. Seven subjects showed positive titres of IgE-class milk-specific antibodies, and five showed a clinical response. CONCLUSION: This re-examination study showed that CMA in infancy, even when properly treated, has significant clinical consequences by posing special risks for respiratory atopy and persistence of atopic dermatitis as well as positive SPT and recurrent ear infections. However, each of these clinical manifestations seems to have an independent curriculum unrelated to the persistence of CMA itself.     

Sesame food allergy and sensitization in children: the natural history and long-term follow-up

Sesame food allergy (SFA) in children is an increasingly recognized one in many countries. Our objective was to describe the course and natural history of SFA. Seventy-four patients sensitized to sesame were evaluated using clinical records, questionnaires, skin prick tests (SPT), in vitro specific immunoglobulin (sIg) E, and oral challenges (OC) and categorized into three groups: group A: patients who experienced allergic reaction after ingestion of sesame-containing food (n = 45); group B: patients evaluated for atopic dermatitis and found to be sesame SPT-positive (n = 11); group C: patients with sensitization to sesame allergen (n = 18). Group A patients were followed for an average of 6.7 yr. Analysis of our results revealed that 76% of patients in group A developed the allergy by the age of 2. The median age at onset of allergy in these patients was 1 yr. Immediate reaction to a minimal amount of sesame was characteristic. Skin was the most common site of involvement, followed by respiratory and gastrointestinal systems. Tolerance developed in only 20% of the patients. High sIgE (>0.15 IU) was demonstrated only in 75% of those in which it was examined. Sixteen patients performed oral sesame food challenge which was found positive in 88%. No correlation was found between the size of SPT and the level of in vitro sesame IgE antibodies, the outcome of OC results, and the development of tolerance to sesame. In conclusion, SFA tends to appear early in life, but unlike cow's milk and egg allergy, persists in 80% of the cases. Typical reactions combined with positive sesame SPT are reliable for diagnosis.     

The pendulum between food protein-induced enterocolitis syndrome and IgE-mediated milk allergy

The transition from milk protein-induced enterocolitis syndrome to IgE-mediated milk allergy is uncommon. Herein, we describe three infants that suffered from recurrent vomiting and restlessness in response to cow's milk formula with negative skin prick to milk and therefore diagnosed as milk protein-induced enterocolitis syndrome. After recovering and reintroducing cow's milk formula, they developed disseminated urticaria and positive skin prick test to cow milk compatible with IgE-mediated milk allergy. CONCLUSION: An infant that recovers from cow milk food-induced enterocolitis syndrome might develop afterward IgE-mediated cow milk allergy.     

Safety and efficacy of a new extensively hydrolyzed formula for infants with cow's milk protein allergy

Cow's milk protein allergy (CMPA) is best treated by complete elimination of cow's milk from the diet. For infants with CMPA who cannot be breast-fed, formulas based on extensively hydrolyzed proteins or on amino acids are the preferred substitutes for cow's milk-based formulas. In this study, we compared the tolerance and growth of infants with CMPA who were fed a new extensively hydrolyzed formula containing lactose (eHF) with those who were fed an amino acid formula (AAF). This was a prospective, multi-center, randomized, reference-controlled study. Seventy-seven infants <12 months old with suspected CMPA were enrolled. In 66 of these, CMPA was confirmed by oral challenge in a double-blind, placebo-controlled food challenge (DBPCFC) or by a medical history of severe allergic reaction to cow's milk and a positive skin prick test. These infants were then tested for their reaction to eHF and AAF in a DBPCFC. All infants tolerated both formulas and were randomized to receive either eHF (n = 34) or AAF (n = 32) for 180 days. Growth (weight, length, and head circumference) and tolerance [skin, gastro-intestinal, and respiratory tract symptoms of allergy] were evaluated after 30, 60, 90, and 180 days. There were no significant differences between the two groups in any of the growth measurements. Length and head circumference were similar to Euro-growth standards, but weight was slightly lower. Gastro-intestinal and respiratory tract symptoms of allergy were also similar in the two groups. However, whereas SCORAD scores for atopic dermatitis remained constant throughout the study in infants-fed eHF, there was a slight decrease in those fed AAF. Infants-fed eHF had significantly fewer incidents of vomiting than infants-fed AAF and a significantly higher frequency of soft stools. The new eHF is safe and well tolerated in infants diagnosed with CMPA.     

The spectrum of cow''s milk allergy

Childhood cow's milk allergy is a diagnosis encompassing various syndromes. Antigen-immunoglobulin E (IgE) antibody interaction is classically involved in mast cell degranulation in IgE-mediated food allergy, while non-IgE mediated cow's milk allergy is mostly mediated by cellular mechanisms. The diagnosis of cow's milk allergy largely relies on a good knowledge of the clinical expression of the disease. In this educational review series, we describe three cases of cow's milk allergy, first a 7-yr-old girl with persisting IgE-mediated cow's milk allergy, second a 8-month-old boy with cow's milk induced flares of atopic dermatitis, and third a 6-yr-old boy with sheep and goat milk allergy, in the absence of cow's milk allergy. The cases are discussed and summarized with more general recommendations for the clinical management of cow's milk allergy.     

Efficacy of donkey's milk in treating highly problematic cow's milk allergic children: An in vivo and in vitro study

Successful therapy in cow's milk protein allergy rests on completely eliminating cow's milk proteins from the child's diet: it is thus necessary to provide a replacement food. This prospective study investigated tolerance of donkey's milk in a population of 46 selected children with cow's milk protein allergy, for whom it was not possible to use any cow's milk substitute. Thirty-eight children (82.6%) liked and tolerated donkey's milk at the challenge and for the entire duration of follow-up. Catch-up growth was observed in all subjects with growth deficit during cow's milk proteins challenge. The degree of cross-reactivity of immunoglobulin E (IgE) with donkey's milk proteins was very weak and aspecific. Donkey's milk was found to be a valid alternative to both IgE-mediated and non-IgE-mediated cow's milk proteins allergy, including in terms of palatability and weight-height gain.     

Frequency of food allergy in a pediatric population from Spain

We evaluated the prevalence and characteristics of the principal foods implicated in 355 children diagnosed with IgE-mediated food allergy. Diagnosis was established on the basis of positive clinical history for the offending food, positive specific IgE by skin prick test and RAST, and open food challenge. Our results showed the principal foods involved in allergic reactions are: eggs, fish, and cow's milk. These are followed in frequency by fruits (peaches, hazelnuts and walnuts), legumes (lentils, peanuts and chick peas) and other vegetables (mainly sunflower seeds). The legumes demonstrated the highest degree of clinical cross-reactivity. Most patients with food allergy reacted to one or two foods (86.7%). Only 13.3% of patients reacted to 3 or more foods, mostly to legumes and fruits. We found that food allergy begins most frequently in the first (48.8%) and second (20.4%) years of life. Allergy to proteins of cow's milk, egg, and fish begins predominantly before the second year, demonstrating a clear relationship with the introduction of these foods into the child's diet. Allergy to foods of vegetable origin (fruits, legumes and other vegetables) begins predominantly after the second year.;     

Fractional exhaled nitric oxide in infants during cow's milk food challenge

Cow's milk allergy (CMA) is the most common food allergy in early childhood. The golden standard for the diagnosis of CMA is a food challenge after a period of elimination. Increased levels of fractional exhaled nitric oxide (FE_NO) have been shown after bronchial allergen provocation. We evaluated whether FE_NO may also be a predictor of a positive reaction during cow's milk challenge in infants. Forty-four infants [mean age (range): 4.2 (3.7–4.6) months] suspected of CMA underwent an open food challenge with cow's milk formula administered in ascending quantities, starting with 2 ml and then 6, 20, 60 and 200 ml until a clinical reaction occurred. Off-line FE_NO samples were obtained during tidal breathing by means of a facemask covering infants' nose and mouth. FE_NO was measured twice before the challenge (baseline), immediately before each new dose of milk and after a positive reaction or after the last dose of milk. Eleven children showed immediate positive clinical responses to cow's milk, whereas 13 infants presented only a late-type reaction. FE_NO values before or after a positive reaction (either immediate or late) were not different from FE_NO values at baseline. Baseline FE_NO in infants with a positive reaction did not differ from FE_NO in infants without a reaction at any time point. We conclude that FE_NO values are not predictive and not related to the occurrence of a positive reaction during a cow's milk challenge in infants, suggesting that a positive reaction may not result from eosinophilic activation.     

General paediatricians and the case of resolving peanut allergy

Children with peanut allergy are almost always advised to avoid nuts for life. There have been recent reports from academic centres that in some cases the allergy might resolve and thus these dietary restrictions can be lifted. To evaluate resolution of peanut allergy in a selected group of children in a general paediatric setting. Children 4-16 yr old with a clear history of an allergic reaction to peanuts who had not had any reaction in the previous 2 yr were eligible. Specific immunoglobulin E (IgE) or skin prick test (SPT) at the time of diagnosis was sought. A SPT and specific IgE was then done and if this was 相似文献   

Skin prick testing predicts peanut challenge outcome in previously allergic or sensitized children with low serum peanut-specific IgE antibody concentration

Peanut allergy is transient in some children but it is not clear whether quantitating peanut-specific IgE by Skin Prick Test (SPT) adds additional information to fluorescent-enzyme immunoassay (FEIA) in discriminating between allergic and tolerant children. To investigate whether SPT with a commercial extract or fresh foods adds additional predictive information for peanut challenge in children with a low FEIA (<10 k UA/L) who were previously sensitized, or allergic to peanuts. Children from a hospital-based allergy service who were previously sensitized or allergic to peanuts were invited to undergo a peanut challenge unless they had a serum peanut-specific IgE>10 k UA/L, a previous severe reaction, or a recent reaction to peanuts (within two years). SPT with a commercial extract, raw and roasted saline soaked peanuts was performed immediately prior to open challenge in hospital with increasing quantity of peanuts until total of 26.7 g of peanut was consumed. A positive challenge consisted of an objective IgE mediated reaction occurring during the observation period. 54 children (median age of 6.3 years) were admitted for a challenge. Nineteen challenges were positive, 27 negative, five were indeterminate and three did not proceed after SPT. Commercial and fresh food extracts provided similar diagnostic information. A wheal diameter of >or=7 mm of the commercial extract predicted an allergic outcome with specificity 97%, positive predictive value 93% and sensitivity 83%. There was a tendency for an increase in SPT wheal since initial diagnosis in children who remained allergic to peanuts while it decreased in those with a negative challenge. The outcome of a peanut challenge in peanut sensitized or previously allergic children with a low FEIA can be predicted by SPT. In this cohort, not challenging children with a SPT wheal of >or=7 mm would have avoided 15 of 18 positive challenges and denied a challenge to one out of 27 tolerant children.