Evaluation of the utility of atopy patch testing, skin prick testing, and total and specific IgE assays in the diagnosis of cow's milk allergy

Consensus on the diagnosis and treatment of cow's milk protein allergy of the Latin American Society for Pediatric Gastroenterology, Hepatology and Nutrition

Cow's milk protein allergy (CMPA) is the most frequent cause of food allergy in the first months of life. Despite the fact that there are different guidelines and recommendations on the management of children with CMPA, there continues to be great variability in diagnostic and therapeutic criteria in Latin America. The Food Allergy Working Group of the Latin American Society for Pediatric Gastroenterology, Hepatology and Nutrition summoned a group of Latin American experts to reach a consensus and formulate a document to unify diagnostic and therapeutic criteria for CMPA. Three teams were formed, each with a coordinator, and the members of each team developed a series of statements for their corresponding module: a) clinical manifestations and diagnosis; b) diagnostic tools, and c) treatment. A search of the medical literature was carried out to support the information presented in each module and 28 statements were then selected. The statements were discussed, after which they were evaluated by all the experts, utilizing the Delphi method. Their opinions on statement agreement or disagreement were anonymously issued. The final statements selected were those with above 75% agreement and their corresponding recommendations were formulated, resulting in the document presented herein.

Cows' Milk Allergy-Associated Constipation: When to Look for It? A Narrative Review

Constipation is a very common disorder, mostly functional in nature, that may persist for years in up to 35-52% of children. Food allergy prevalence, severity and persistence are increasing over time, and cows' milk protein is the commonest food allergen recognised to affect gastrointestinal motility in children. There is mounting evidence of the role of cows' milk (CM) allergy (CMA) in children with constipation. With this narrative review, we aim to provide clinicians with an updated and critical overview of food allergy-associated constipation. We searched Embase, Medline and the Cochrane Library, using keywords related to the topic. Only reviews and studies including children aged 0-17 years that were published in English were considered. Constipation has been reported in 4.6% of infants with CMA; the prevalence of food allergy underlying chronic constipation in children resistant to conventional treatment and presenting to tertiary clinics ranges between 28% and 78%. The identification of predisposing risk factors and of a specific phenotype of food allergy-induced constipation remains elusive. No allergic tests, radiological or motility investigations achieve sufficient sensitivity and specificity to screen children for CMA-related constipation. A 4-week cows' milk protein (CMP) elimination diet may be considered for children with chronic constipation resistant to conventional treatment and who lack alarm sign/symptoms of organic diseases. In subjects with ameliorated symptoms on CMP elimination, the diagnosis of CMA should be confirmed by a food challenge to avoid an unnecessary protracted diet.

Food allergy: an updated review on pathogenesis, diagnosis, prevention and management

Food allergy (FA) is an adverse immunologic response triggered by normally innocuous food protein antigens.  FA can be broadly classified into those that are IgE mediated, those that are mediated by both IgE-dependent and IgE-independent pathways (mixed), and those that are not IgE mediated  Immunoglobulin E. (IgE)-mediated reaction is characterized by rapid onset of symptoms involving respiratory, gastrointestinal, dermatologic and cardiovascular systems; mixed and non-IgE-mediated has a longer onset and manifests primary in the gastrointestinal tract and skin. The diagnosis of food allergy is based on clinical history, diagnostic testing (skin prick test and allergen-specific IgE levels in the serum), elimination diet and, oral food challenge. In recent years the diagnosis and treatment of pediatric FA have notably improved. In the diagnostic pathway of FA an important recent innovation is the CRD introduction.  This resulted in the possibility of improving diagnostic accuracy through FA prediction severity and prognosis and thereby decreasing the OCF necessity. Recent studies emphasize the possibility of preventing FA through early introduction of food (peanuts and egg) to high-risk infants. FA management is based on avoidance of offending food and prompt treatment of allergic reaction. Currently under study are recently developed treatment approaches for FA management including specific OIT.

Diagnosis and management of cow's milk protein allergy in Turkey: Region-specific recommendations by an expert-panel

Cow's milk protein allergy (CMPA) is the most common type of food-allergy in younger children. Prognosis is usually good, with most children developing tolerance before school age. Children may present with a wide spectrum of symptoms that range from mild to severe; skin reactions such as angioedema and urticaria and gastrointestinal symptoms are the most common presentations of CMPA. Approximately one-third of CMPA patients suffer from multiple food-allergies; severe conditions such as anaphylactic shock (9%), eosinophilic esophagitis (4.7%), and food-protein induced enterocolitis (1%) may also develop in some children. Timely and accurate diagnosis and management is essential for proper growth and development of children with CMPA. In this expert consensus report, we aimed to adapt current understandings in the CMPA field to the specific conditions in Turkey and health system to help physicians with their day-to-day decision making.

Oral Food Challenge

Oral food challenge (OFC) is the gold standard for diagnosis of IgE-mediated and non-IgE mediated food allergy. It is usually conducted to make diagnosis, to monitor for resolution of a food allergy, or to identify the threshold of responsiveness. Clinical history and lab tests have poor diagnostic accuracy and they are not sufficient to make a strict diagnosis of food allergy. Higher concentrations of food-specific IgE or larger allergy prick skin test wheal sizes correlate with an increased likelihood of a reaction upon ingestion. Several cut-off values, to make a diagnosis of some food allergies (e.g., milk, egg, peanut, etc.) without performing an OFC, have been suggested, but their use is still debated. The oral food challenge should be carried out by experienced physicians in a proper environment equipped for emergency, in order to carefully assess symptoms and signs and correctly manage any possible allergic reaction. This review does not intend to analyse comprehensively all the issues related to the diagnosis of food allergies, but to summarize some practical information on the OFC procedure, as reported in a recent issue by The Expert Review of Food Allergy Committee of Italian Society of Pediatric Allergy and Immunology (SIAIP).

The diagnostic value of APT for food allergy in children: a systematic review and meta-analysis

BACKGROUND

The role of atopy patch test (APT) in the diagnosis of food allergy (FA) remains largely controversial. In our meta-analysis, we aimed to evaluate the accuracy of APT for diagnosing FA in children.

METHODS

Pubmed, Embase and Cochrane Library were searched for studies regarding the diagnostic value of APT for FA in children compared to oral food challenge (double-blind placebo-controlled food challenge and/or open food challenge). The last search was conducted on November 11, 2017. Two reviewers independently screened relevant studies and assessed the quality by QUADAS-2. Meta-analysis was performed to calculate the pooled sensitivity, specificity, DOR (diagnostic odds ratio), PLR (positive likelihood ratio), NLR (negative likelihood ratio) with their 95% confidence intervals (CIs). Subgroup analyses were conducted according to different food allergens, atopic dermatitis, gastrointestinal symptoms, and age younger than 3 years.

RESULTS

Forty-one studies were included in the meta-analysis. The pooled sensitivity, specificity, PLR, NLR and DOR were 50.30% (95% CI 48.40%-52.30%), 86.60% (95% CI 85.30%-87.80%), 3.405 (95% CI 2.594-4.470), 0.545 (95% CI 0.469-0.634) and 7.528 (95% CI 5.507-11.206), respectively. However, for children with FA-related gastrointestinal symptoms, the pooled sensitivity and specificity were 57.40% (95% CI 52.10%-62.50%) and 91.50% (95% CI 88.30%-94.10%) respectively.

CONCLUSIONS

Our findings suggest that APT is specific but not sensitive for diagnosing FA in children, especially in children with FA-related gastrointestinal symptoms.

Specific IgE and skin prick tests to diagnose allergy to fresh and baked cow's milk according to age: a systematic review

BACKGROUND

The diagnosis of IgE-mediated cow's milk allergy is often based on anamnesis, and on specific IgE (sIgE) levels and/or Skin Prick Tests (SPT), which have both a good sensitivity but a low specificity, often causing positive results in non-allergic subjects. Thus, oral food challenge is still the gold standard test for diagnosis, though being expensive, time-consuming and possibly at risk for severe allergic reactions.

AIM

The aim of the present study was to perform a systematic review of the studies that have so far analyzed the positive predictive values for sIgE and SPT in the diagnosis of allergy to fresh and baked cow's milk according to age, and to identify possible cut-offs that may be useful in clinical practice.

METHODS

A comprehensive search on Medline via PubMed and Scopus was performed August 2017. Studies were included if they investigated possible sIgE and/or SPT cut-off values for cow's milk allergy diagnosis in pediatric patients. The quality of the studies was evaluated according to QUADAS-2 criteria.

RESULTS

The search produced 471 results on Scopus, and 2233 on PubMed. Thirty-one papers were included in the review and grouped according to patients' age, allergen type and cooking degree of the milk used for the oral food challenge. In children < 2 years, CMA diagnosis seems to be highly likely when sIgE to CM extract are ≥ 5 KU_A/L or when SPT with commercial extract are above 6 mm or Prick by Prick (PbP) with fresh cow's milk are above 8 mm. Any cut-offs are proposed for single cow's milk proteins and for baked milk allergy in children younger than 2 years. In Children ≥ 2 years of age it is hard to define practical cut-offs for allergy to fresh and baked cow's milk. Cut-offs identified are heterogeneous.

CONCLUSIONS

None of the cut-offs proposed in the literature can be used to definitely confirm cow's milk allergy diagnosis, either to fresh pasteurized or to baked milk. However, in children < 2 years, cut-offs for specific IgE or SPT seem to be more homogeneous and may be proposed.

Treatment of Eczema: Corticosteroids and Beyond

Atopic dermatitis (AD) is a chronic inflammatory skin condition that requires a manifold approach to therapy. The goal of therapy is to restore the function of the epidermal barrier and to reduce skin inflammation. This can be achieved with skin moisturization and topical anti-inflammatory agents, such as topical corticosteroids and calcineurin inhibitors. Furthermore, proactive therapy with twice weekly use of both topical corticosteroids and calcineurin inhibitors in previously affected areas has been found to reduce the time to the next eczematous flare. Adjunctive treatment options include wet wrap therapy, anti-histamines, and vitamin D supplementation. Bacterial colonization, in particular Staphylococcus aureus, can contribute to eczematous flares and overt infection. Use of systemic antibiotics in infected lesions is warranted; however, empiric antibiotics use in uninfected lesions is controversial. Local antiseptic measures (i.e., bleach baths) and topical antimicrobial therapies can be considered in patients with high bacterial colonization. Difficult-to-treat AD is a complex clinical problem that may require re-evaluation of the initial diagnosis of AD, especially if the onset of disease occurs in adulthood. It may also necessitate evaluation for contact, food, and inhaled allergens that may exacerbate the underlying AD. There are a host of systemic therapies that have been successful in patients with difficult-to-treat AD, however, these agents are limited by their side effect profiles. Lastly, with further insight into the pathophysiology of AD, new biological agents have been investigated with promising results.

Histopathologic findings in children diagnosed with cow's milk protein allergy

BACKGROUND

Cow's milk protein allergy is the most common cause of food allergy. The challenge test, either open or doubled-blind with a placebo control, is regarded as the criterion standard. Endoscopy and histologic findings are considered a method that can aid in the diagnosis of this entity.

AIMS

The aim of this study was to describe the histopathologic findings in children suspected of cow's milk protein allergy that were seen at our hospital.

MATERIAL AND METHODS

A descriptive, observational study was conducted on 116 children clinically suspected of presenting with cow's milk protein allergy that were seen at the Department of Gastroenterology and Nutrition of the Instituto Nacional de Pediatría. Upper endoscopy and rectosigmoidoscopy with biopsies were performed and the findings were described.

RESULTS

Of the 116 patients, 64 (55.17%) were girls and 52 (44.83%) were boys. The rectum was the site with the greatest presence of eosinophils per field in both groups, followed by the duodenum. In general, more than 15 eosinophils were found in 46% of the patients.

CONCLUSIONS

Between 40 and 45% of the cases had the histologic criterion of more than 15 to 20 eosinophils per field and the rectosigmoid colon was the most affected site. Therefore, panendoscopy and rectosigmoidoscopy with biopsy and eosinophil count are suggested.

Optimizing the diagnosis of food allergy

Accurately diagnosing a patient with a possible food allergy is important to avoid unnecessary dietary restrictions and prevent life-threatening reactions. Routine testing modalities have limited accuracy, and an oral food challenge is often required to make a definitive diagnosis. Given that they are labor intensive and risk inducing an allergic reaction, several alternative diagnostic modalities have been investigated. Testing for IgE antibodies to particular protein components in foods has shown promise to improve diagnostics and has entered clinical practice. Additional modalities show potential, including epitope binding, T-cell studies, and basophil activation.

Guidelines of care for the management of atopic dermatitis: Section 4. Prevention of disease flares and use of adjunctive therapies and approaches

Atopic dermatitis is a common, chronic inflammatory dermatosis that can affect all age groups. This evidence-based guideline addresses important clinical questions that arise in its management. In this final section, treatments for flare prevention and adjunctive and complementary therapies and approaches are reviewed. Suggestions on use are given based on available evidence.

The diagnosis of food allergy: a systematic review and meta-analysis

BACKGROUND

We investigated the accuracy of tests used to diagnose food allergy.

METHODS

Skin prick tests (SPT), specific-IgE (sIgE), component-resolved diagnosis and the atopy patch test (APT) were compared with the reference standard of double-blind placebo-controlled food challenge. Seven databases were searched and international experts were contacted. Two reviewers independently identified studies, extracted data, and used QUADAS-2 to assess risk of bias. Where possible, meta-analysis was undertaken.

RESULTS

Twenty-four (2831 participants) studies were included. For cows' milk allergy, the pooled sensitivities were 53% (95% CI 33-72), 88% (95 % CI 76-94), and 87% (95% CI 75-94), and specificities were 88% (95% CI 76-95), 68% (95% CI 56-77), and 48% (95% CI 36-59) for APT, SPT, and sIgE, respectively. For egg, pooled sensitivities were 92% (95% CI 80-97) and 93% (95% CI 82-98), and specificities were 58% (95% CI 49-67) and 49% (40-58%) for skin prick tests and specific-IgE. For wheat, pooled sensitivities were 73% (95% CI 56-85) and 83% (95% CI 69-92), and specificities were 73% (95% CI 48-89) and 43% (95% CI 20-69%) for SPT and sIgE. For soy, pooled sensitivities were 55% (95% CI 33-75) and 83% (95% CI 64-93), and specificities were 68% (95% CI 52-80) and 38% (95% CI 24-54) for SPT and sIgE. For peanut, pooled sensitivities were 95% (95% CI 88-98) and 96% (95% CI 92-98), and specificities were 61% (95% CI 47-74), and 59% (95% CI 45-72) for SPT and sIgE.

CONCLUSIONS

The evidence base is limited and weak and is therefore difficult to interpret. Overall, SPT and sIgE appear sensitive although not specific for diagnosing IgE-mediated food allergy.

Diagnosis of food allergy

Diagnosis of food allergy can be challenging. Given the limited specificity of available allergy tests, these need to be interpreted in light of pre-test probability that is determined by a careful history. Using likelihood ratios calculated from previous publication may allow a more individualized assessment. This approach is likely to be most useful in patients with low to moderate results, below the 95% positive predictive value for that food. This review covers the diagnostic approach of immunoglobulin E-mediated food allergy. We first focus on the pre-test clinical assessment of a patient with a suspected food allergy. We then compare currently available diagnostic tests and discuss their performance for frequent food allergens. Finally, we conclude with the interpretation of allergy tests in light of the pre-test assessment to determine final probability of food allergy and indications for referral to an allergy specialist for food challenge.

Skin prick test and specific serum IgE in the diagnostic evaluation of suspected cow's milk and hen's egg allergy in children: does one replace the other?

BACKGROUND

The measurement of specific serum immunoglobulin E (sIgE) and the skin prick test (SPT) are accepted tools in the diagnostic work-up of suspected food allergy. Often only one of the methods is used to determine sensitization; however, it is still under debate whether these two methods can be used interchangeably.

OBJECTIVES

To investigate the concordance of SPT and sIgE serum assays with regard to suspected food allergy.

METHODS

In 395 children referred to our clinic with suspected cow's milk allergy and in 268 children with suspected hen's egg allergy specific immunoglobulin E (IgE) was measured, a SPT and an oral food challenge performed. A weal size ≥ 3 mm and sIgE ≥ 0.35 kU/L were considered positive. The weal size of the SPT and the level of food-specific IgE were tested for correlation for each allergen.

RESULTS

Of the 395 (23%) children orally challenged with cow's milk, 92 showed no corresponding results for SPT and sIgE as either positive or negative. For hen's egg, in 27 of 268 (10%) children differing test results for SPT and sIgE in serum were obtained. Moreover, regarding the quantitative values for sIgE and SPT in children with or without clinically relevant food allergy, sIgE and SPT correlated badly.

CONCLUSIONS

The concordance between SPT and sIgE is surprisingly low for cow's milk and hen's egg on an individual basis. Therefore, the tests should not be used interchangeably. Especially in children who receive a negative test result the alternative test should also be used. Furthermore, our data indicate again that oral food challenges are still the method of choice to diagnose food allergies.

Cow's milk allergy as a global challenge

PURPOSE OF REVIEW

Cow's milk is a leading cause of food allergy especially in infants and children. 'Diagnosis and Rationale for Action against Cow's Milk Allergy' published by the World Allergy Organization has underlined that there is not enough information concerning geographical trends in cow's milk allergy (CMA) in children or adults. Experts from Australia, Asia, North America, Latin America, the Middle East and Europe have gathered together in a 2-day meeting in order to present various regional approaches to CMA. This report is a summary of the information that was presented at this meeting.

RECENT FINDINGS

Even though there seems to be uniformity concerning the diagnosis and treatment of CMA, the diagnostic approach to CMA shows variations among different regions. Common concerns were inadequate applications of challenge tests for the diagnosis and inadequate supply of the cow's milk substitute formulas.

SUMMARY

CMA is a global challenge and collaboration of the national and international scientific communities is essential to produce and update practical guidelines for CMA.

Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel

Food allergy is an important public health problem that affects children and adults and may be increasing in prevalence. Despite the risk of severe allergic reactions and even death, there is no current treatment for food allergy: the disease can only be managed by allergen avoidance or treatment of symptoms. The diagnosis and management of food allergy also may vary from one clinical practice setting to another. Finally, because patients frequently confuse nonallergic food reactions, such as food intolerance, with food allergies, there is an unfounded belief among the public that food allergy prevalence is higher than it truly is. In response to these concerns, the National Institute of Allergy and Infectious Diseases, working with 34 professional organizations, federal agencies, and patient advocacy groups, led the development of clinical guidelines for the diagnosis and management of food allergy. These Guidelines are intended for use by a wide variety of health care professionals, including family practice physicians, clinical specialists, and nurse practitioners. The Guidelines include a consensus definition for food allergy, discuss comorbid conditions often associated with food allergy, and focus on both IgE-mediated and non-IgE-mediated reactions to food. Topics addressed include the epidemiology, natural history, diagnosis, and management of food allergy, as well as the management of severe symptoms and anaphylaxis. These Guidelines provide 43 concise clinical recommendations and additional guidance on points of current controversy in patient management. They also identify gaps in the current scientific knowledge to be addressed through future research.

Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel

Food allergy is an important public health problem that affects children and adults and may be increasing in prevalence. Despite the risk of severe allergic reactions and even death, there is no current treatment for food allergy: the disease can only be managed by allergen avoidance or treatment of symptoms. The diagnosis and management of food allergy also may vary from one clinical practice setting to another. Finally, because patients frequently confuse nonallergic food reactions, such as food intolerance, with food allergies, there is an unfounded belief among the public that food allergy prevalence is higher than it truly is. In response to these concerns, the National Institute of Allergy and Infectious Diseases, working with 34 professional organizations, federal agencies, and patient advocacy groups, led the development of clinical guidelines for the diagnosis and management of food allergy. These Guidelines are intended for use by a wide variety of health care professionals, including family practice physicians, clinical specialists, and nurse practitioners. The Guidelines include a consensus definition for food allergy, discuss comorbid conditions often associated with food allergy, and focus on both IgE-mediated and non-IgE-mediated reactions to food. Topics addressed include the epidemiology, natural history, diagnosis, and management of food allergy, as well as the management of severe symptoms and anaphylaxis. These Guidelines provide 43 concise clinical recommendations and additional guidance on points of current controversy in patient management. They also identify gaps in the current scientific knowledge to be addressed through future research.

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.

The diagnosis of food allergy in children

PURPOSE OF REVIEW

To give an update about the optimal diagnostic work-up for children with suspected food allergy.

RECENT FINDINGS

Food allergy has become a very severe health problem not only for many children and parents, but also for the entire medical and paramedical community. The financial and social costs related to these conditions are increasing, but, contemporarily, basic and clinical research are deeply involved in the search of possible solutions to facilitate the management of these patients.

SUMMARY

Food allergy is defined as an abnormal immunological reaction to food proteins, which causes an adverse clinical reaction. Over 90% of food allergies in childhood are caused by eight foods: cow's milk, hen's egg, soy, peanuts, tree nuts, wheat, fish and shellfish. The evaluation of a child with suspected food allergy includes detailed medical history, physical examination, screening tests and response to elimination diet and to oral food challenge. None of the screening tests, alone or in combination, can definitely diagnose or exclude it. The main principle of food allergy management is avoidance of the offending antigen. An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the child's nutritional status and growth.

Allergen-specific helper T cell response in patients with cow's milk allergy: Simultaneous analysis of proliferation and cytokine production by carboxyfluorescein succinimidyl ester dilution assay

BACKGROUND

The role of antigen-specific T cells in the allergic reaction to cow's milk or in tolerance induction is not yet fully understood.

OBJECTIVE

This study was designed to analyse both cow's milk protein (CMP)-specific T cell proliferation and cytokine production simultaneously in children with cow's milk allergy (CMA) in comparison with subjects with various allergic backgrounds.

METHODS

Carboxyfluorescein succinimidyl ester was used to detect cow's milk-specific T cells by flow cytometry. The intra-cytoplasmic cytokine production of these antigen-specific T cells was also analysed.

RESULTS

Significant differences of both CMP-specific CD4+ cell proliferation and cytokine production between CMA and non-allergic children were observed. While the proliferative responses of children who recently outgrew CMA were not significantly different from those of patients, the patterns of cytokine production were similar to those of non-allergic children.

CONCLUSION

These results suggest that the presence of CMP-specific T cell clones per se does not produce CMA, but that the T-helper type 2-skewed pattern of those T cells is associated with adverse reactions. Although it is not possible to distinguish between individual patients with and without CMA on the basis of CFSE assays, these results contribute to the understanding of the pathogenesis and tolerance induction of CMA.

Diagnostic accuracy of the atopy patch test in children with food allergy-related gastrointestinal symptoms

BACKGROUND

Little is known about the diagnostic accuracy of atopy patch tests (APT) in the clinical practice of pediatric gastroenterology. Moreover, APTs containing purified food extracts have recently become available, but their diagnostic accuracy is largely undefined.

PATIENTS AND METHODS

We evaluated the diagnostic accuracy of food challenge, skin prick test (SPT), serum specific IgE determination, and APT using fresh food and commercial food extracts in parallel in children referred for suspected food allergy-related gastrointestinal symptoms.

RESULTS

Eighty-nine food challenges were performed in 60 patients (38 boys, median age 23 months, range 3-48 months): 31 tested positive for cow's milk (CM), 19 for hen's egg (HE), and two for wheat. Specific immunoglobulin E (IgE) determination, and SPT, respectively, were positive in 7/31 and 14/31 of patients with cow's milk allergy (CMA), and in 7/19 and 7/19 with HE allergy. The results of APT with fresh food vs a commercial assay were (1) CM: sensitivity: 64.5%vs 6.4%, specificity 95.8%vs 95.6%, positive predictive value (PPV) 95.2%vs 66.6% and negative predictive value (NPV) 67.6%vs 43.1%; (2) HE: sensitivity 84.2%vs 5.2%, specificity 100%vs 100%, PPV 100%vs 100% and NPV 75.0%vs 33.3%.

CONCLUSIONS

Atopy patch test is a useful tool in the diagnostic work up of children with food-allergy-related gastrointestinal symptoms. The diagnostic accuracy of ATP was higher with fresh food than with commercial food extracts.

In vivo and in vitro allergy diagnostics: it's time to reappraise the costs

BACKGROUND

The in vivo skin prick test (SPT) is widely considered less expensive than in vitro gamma-immunoglobulin E (IgE) determination in the diagnosis of allergy. The aim of the present paper is to evaluate the relevance of component-resolved in vitro diagnosis in comparison to extract-based diagnosis and the relative global costs in relation to clinical outcomes.

METHODS

For 50 individuals with suspected seasonal allergic rhinitis, we compared the costs of skin testing with those of specific IgE antibody measurement.

RESULTS

The costs were higher for in vitro than in vivo testing. However, the clinical information obtained using recombinant reagents allowed correct identification of the sensitizing molecule.

CONCLUSIONS

Recombinant allergens for specific IgE in vitro measurement provide more reliable information for immunotherapy prescription. This should be translated into a significant reduction in the overall costs sustained by the healthcare system.

Rhinosinusitis derived Staphylococcal enterotoxin B plays a possible role in pathogenesis of food allergy

BACKGROUND

Staphylococcal enterotoxin B (SEB) is a potent immunomodulator and implicated with pathogenesis of inflammatory diseases mediated by Th1 or Th2 dominant immune responses. The objective of this study is to determine a possible association between rhinosinusitis derived SEB and pathogenesis of food allergy (FA).

METHODS

The study included chronic rhinosinusitis (CRS) patients with FA (N = 46) or without FA (N = 33). Controls included FA patients without CRS (N = 26) and healthy volunteers (N = 25). In CRS patients, we assessed the parameters associated with FA including prick skin test (PST) reactivity to food allergens, serum levels of allergen-specific IgE and cytokines (IL-4, IL-13, IFN-I3), and the number/reactivity of food-allergen specific Th1/Th2 cells in the peripheral blood before and 2 months after sinus surgery. Changes of these parameters were evaluated in comparison with changes in SEB concentration in the sinus lavage and stool samples and also in vitro reactivity to SEB. In CRS patients with FA, we also assessed changes in reactivity to oral challenge of offending food before and after sinus surgery.

RESULTS

Two months following sinus surgery, we observed statistically significant reduction in PST and oral challenge reactivity in CRS patients with FA in parallel to decrease in serum levels of Th2 cytokines (IL-4 and IL-13) and allergen specific IgE. Improvement of reactivity to food allergens was positively associated with decline in SEB concentrations in the sinus lavage and stool samples. In vitro study results also indicated a role of SEB in aggravation of Th2 skewed responses to food allergens. Such changes were not observed in CRS-non FA patients or control FA patients.

CONCLUSION

The rhinosinusitis derived SEB plays a certain role in the pathogenesis of FA by augmenting and/or maintaining polarized Th2 responses. Removal of SEB-producing pathogens from the rhinosinuses may be beneficial for attenuating the FA symptoms in patients with CRS-FA.