Atopy patch tests, together with determination of specific IgE levels, reduce the need for oral food challenges in children with atopic dermatitis

Is Food-Triggered Atopic Dermatitis a Form of Systemic Contact Dermatitis?

Food allergy in atopic dermatitis is mediated by complex immune interactions between genetics, diet, environment, and the microbiome. When contact between inflamed skin and food antigens occurs, contact hypersensitivity can develop. Consequently, systemic contact dermatitis (SCD) can occur after ingestion of allergenic foods or food additives in the setting of a Th2 response with CLA-positive T cells, triggering dermatitis where skin resident memory lymphocytes reside. This phenomenon explains food-triggered dermatitis. Atopy patch tests (APTs) detect sensitization to food proteins responsible for SCD, which in turn can be confirmed by oral food challenge with delayed interpretation. We summarize the literature on using APTs to identify foods for oral challenge with dermatitis as an outcome. In dermatitis patients at risk for Th2 skewing based on a history of childhood-onset flexural dermatitis, shared decision-making should include a discussion of identifying and avoiding food and food additive triggers, as well as identifying and avoiding all contact allergens, prior to initiation of systemic therapy for dermatitis.

The role of the atopy patch test in the diagnostic work-up of non-IgE gastrointestinal food allergy in children: a systematic review

The "Atopy Patch Test" (APT) has been proposed as a diagnostic tool for food allergies (FA), especially in children with FA-related gastrointestinal symptoms. However, its diagnostic accuracy is debated, and its usefulness is controversial. The aim of this systematic review was to evaluate the APT diagnostic accuracy compared with the diagnostic gold standard, i.e., the oral food challenge (OFC), in children affected by non-IgE mediated gastrointestinal food allergies, including the evaluation in milk allergic subgroup. Both classical non-IgE mediated clinical pictures and food induced motility disorders (FPIMD) were considered. The search was conducted in PubMed and Scopus from January 2000 to June 2022 by two independent researchers. The patient, intervention, comparators, outcome, and study design approach (PICOS) format was used for developing key questions, to address the APT diagnostic accuracy compared with the oral food challenge (OFC). The quality of the studies was assessed by the QUADAS-2 system. The meta-analysis was performed to calculate the pooled sensitivity, specificity, DOR (diagnostic odds ratio), PLR (positive likelihood ratio), and NLR (negative likelihood ratio) with their 95% confidence intervals (CI). Out of the 457 citations initially identified via the search (196 on PubMed and 261 on Scopus), 37 advanced to full-text screening, and 16 studies were identified to be included in the systematic review. Reference lists from relevant retrievals were searched, and one additional article was added. Finally, 17 studies were included in the systematic review. The analysis showed that APT has a high specificity of 94% (95%CI: 0.88-0.97) in the group of patients affected by FPIMD. Data showed a high pooled specificity of 96% (95% CI: 0.89-0.98) and the highest accuracy of APT in patients affected by cow's milk allergy (AUC = 0.93).      Conclusion: APT is effective in identifying causative food in children with food-induced motility disorders.  What is Known: • Atopy patch test could be a useful diagnostic test for diagnosing food allergy, especially in children with food allergy-related gastrointestinal symptoms. What is New: • Atopy patch test may be a useful tool in diagnosing non IgE food allergy, especially in children with food-induced gastrointestinal motility disorders and cow's milk allergy.

Diagnostic accuracy of atopy patch test in children with cow's milk allergy

BACKGROUND

The accuracy of an atopy patch test (APT) for fresh cow's milk allergy is controversial. Few studies have focused on commercial extract solutions. We aimed to evaluate the diagnostic performance of the APT in cow's milk allergic children using fresh cow's milk and commercial extracts of cow's milk and its components including casein, α-lactalbumin, and β-lactoglobulin.

METHODS

A prospective study was carried out in children with a history of cow's milk allergy. Children underwent the skin prick test (SPT) and APT with fresh cow's milk, powdered cow's milk, and commercial extracts of cow's milk, casein, α-lactalbumin, and β-lactoglobulin. Oral food challenge (OFC) was confirmed in all children.

RESULTS

A total of 37 patients participated (mean age 13.14 ± 7.26 months). Only 5 (13.51%) patients had positive OFC to cow's milk. The sensitivity of the APT using fresh cow's milk was 40%, specificity was 65.6%, PPV was 15.4%, and NPV was 87.5%. The sensitivity of the APT using powdered cow's milk was 40%, 60.7% for specificity, 15.4% for PPV, and 58% for NPV. The sensitivity and PPV of the APT using commercial solutions of cow's milk, casein, α-lactalbumin, and β-lactoglobulin were zero. The specificities were 90.6%, 93.8%, 100%, and 100% for α-lactalbumin, cow's milk, casein, and β-lactoglobulin, respectively.

CONCLUSIONS

APT using commercial solutions showed higher specificity than fresh milk. The specificity increased using a protein component allergen.

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.

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.

Consensus-based European guidelines for treatment of atopic eczema (atopic dermatitis) in adults and children: part I

This guideline was developed as a joint interdisciplinary European project, including physicians from all relevant disciplines as well as patients. It is a consensus-based guideline, taking available evidence from other guidelines, systematic reviews and published studies into account. This first part of the guideline covers methods, patient perspective, general measures and avoidance strategies, basic emollient treatment and bathing, dietary intervention, topical anti-inflammatory therapy, phototherapy and antipruritic therapy, whereas the second part covers antimicrobial therapy, systemic treatment, allergen-specific immunotherapy, complementary medicine, psychosomatic counselling and educational interventions. Management of AE must consider the individual clinical variability of the disease; highly standardized treatment rules are not recommended. Basic therapy is focused on treatment of disturbed barrier function by hydrating and lubricating topical treatment, besides further avoidance of specific and unspecific provocation factors. Topical anti-inflammatory treatment based on glucocorticosteroids and calcineurin inhibitors is used for flare management and for proactive therapy for long-term control. Topical corticosteroids remain the mainstay of therapy, whereas tacrolimus and pimecrolimus are preferred in sensitive skin areas and for long-term use. Topical phosphodiesterase inhibitors may be a treatment alternative when available. Adjuvant therapy includes UV irradiation, preferably with UVB 311 nm or UVA1. Pruritus is targeted with the majority of the recommended therapies, but some patients may need additional antipruritic therapy. Antimicrobial therapy, systemic anti-inflammatory treatment, immunotherapy, complementary medicine and educational intervention will be addressed in part II of the guideline.

Oral allergy syndrome

OBJECTIVES

To review oral allergy syndrome (OAS).

METHODS

We searched several medical literature data bases with the following key words: "oral allergy syndrome," "OAS," "pollen-food allergy syndrome," "PFAS," "allergy," "diagnosis," "treatment."

RESULTS

Oral allergy syndrome (OAS), also called "pollen-food allergy syndrome," is a type of food allergy brought about by flavors, nuts, raw fruit, and vegetables. The most well-known symptoms are mouth and throat itching, which starts rapidly after a food is placed in the mouth, and that, as a rule, continues for just a couple of minutes after the food has been swallowed. The frequency of OAS with pollen allergy has been reported as 5-8%; 1-2% of patients with OAS with pollen allergy show extreme responses, e.g., anaphylaxis. Birch tree pollen, ragweed pollen, and grass pollen hypersensitivity cause the symptoms. The diagnosis of OAS is confirmed by a positive history and positive skin-prick test result triggered by the food's fresh extract. Oral challenge result is normally positive with the raw food and negative with the similar cooked food.

CONCLUSION

Patients with grass allergy may have a response to peaches, oranges, celery, tomatoes, and melons. Patients with ragweed allergy may show OAS symptoms with melon, cucumber, banana, and zucchini. Physicians should be aware of OAS and know the appropriate treatment.

Unproven Diagnostic Tests for Food Allergy

The gold standard for diagnosis of immunoglobulin E (IgE)-mediated food allergy remains the oral food challenge, with serum IgE testing and skin prick testing serving as acceptable alternatives. However, the increase in prevalence of food allergy (both physician diagnosed and patient suspected) has led patients to pursue a variety of other alternative diagnostic procedures for suspected food allergy, which are reviewed in this article. These procedures (IgG testing, electrodermal testing, cytotoxic testing, provocation/neutralization, and applied kinesiology) have largely been unproven and may lead to unnecessary elimination diets.

Low efficacy of atopy patch test in predicting tolerance development in non-IgE-mediated cow's milk allergy

BACKGROUND

The food atopy patch (APT) test has been used in previous studies to help the diagnosis of non-IgE mediated food allergies (FA). The aim of this study was to evaluate the efficacy of different cow's milk APT preparations to predict oral tolerance in children with previous non-IgE-mediated cow's milk allergy (CMA) diagnosis.

METHODS

Thirty-two patients non-IgE-mediated CMA diagnosed by oral food challenge (OFC) were enrolled to perform APT with three different cow's milk preparations (fresh, 2% in saline solution, 2% in petrolatum) and comparing with a new OFC after at least three months of diet exclusion.

RESULTS

Only six (18.7%) subjects presented positive OFC to cow's milk. No differences in gender, onset symptoms age, OFC age, Z-score, and exclusion period were found between positive and negative OFC patients. Preparations using fresh milk and powdered milk in petrolatum presented sensitivity equal to zero and specificity 92.3% and 96.1%. The preparation using powdered milk in saline solution showed sensitivity and specificity of 33.3% and 96.1%. Two patients presented typical IgE symptoms after OFC.

CONCLUSION

Cow's milk APT presented a low efficacy to predict tolerance in patients with previous non-IgE-mediated CMA and should not be used in clinical routine. The presence of typical IgE reactions after OFC hallmark the necessity of previous IgE-mediated investigation for this patient group.

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.

Atopy patch test in children with atopic dermatitis

BACKGROUND

Atopic dermatitis is frequently associated with food and/or aeroallergen allergy.

OBJECTIVE

To evaluate atopy patch tests (APTs) and skin prick tests (SPTs) in children with atopic dermatitis, using allergen extracts from locally lyophilized foods (cow's milk, egg white, egg yolk, wheat, soy, and shrimp), Dermatophagoides pteronyssinus, Dermatophagoides farinae, and American cockroach.

METHODS

This study was a prospective, self-controlled study in children with atopic dermatitis. APTs, SPTs, and oral food challenge tests were performed in the cases with written informed consent.

RESULTS

Fifty-six children with atopic dermatitis were enrolled. According to the Severity Scoring of Atopic Dermatitis Index, moderate atopic dermatitis was the most common severity (49.1%) followed by mild (20%) and severe atopic dermatitis (13.2%). APT results were positive for food allergens in 49% of participants; SPT results were positive in 54.7%. The sensitivity, specificity, positive predictive value, and negative predictive value of APTs for foods were 40%, 90.2%, 65.2%, and 76.6%, respectively. For SPTs, those values were 40%, 93.9%, 75%, and 77.3%, respectively. APT results for D farinae, D pteronyssinus, and American cockroach were positive in 33.9%, 35.8%, and 21.8% of participants, respectively. SPT results for these allergens were positive in 28.3%, 24.5%, and 9.4% of participants, respectively. No serious complications occurred.

CONCLUSION

APTs with locally prepared lyophilized allergen extracts were safe and had high specificity, median positive predictive value, and low sensitivity for evaluation of suspected food allergy in children with atopic dermatitis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01164293.

Evaluation of canine adverse food reactions by patch testing with single proteins, single carbohydrates and commercial foods

BACKGROUND

Adverse food reaction (AFR) is an important differential diagnosis for the pruritic dog. It is usually diagnosed by feeding an elimination diet with a novel protein and carbohydrate source for eight weeks followed by subsequent food provocation. A previous study demonstrated that patch testing dogs with foods had a high sensitivity and negative predictability for selection of elimination diet ingredients.

HYPOTHESIS/OBJECTIVES

The aim of this study was to investigate patch testing with proteins, carbohydrates and dry commercial dog food in dogs to determine whether there was value in patch testing to aid the diagnosis of canine adverse food reaction.

METHODS

Twenty five privately owned dogs, with confirmed AFR, underwent provocation trials with selected food antigens and patch testing.

RESULTS

For proteins, carbohydrates and dry dog food the sensitivity of patch testing was 100%, 70% and 22.2%, respectively; the negative predictive values of patch testing were 100%, 79% and 72%. The positive predictive values of patch testing for proteins and carbohydrates were 75% and 74%, respectively.

CONCLUSION AND CLINICAL IMPORTANCE

This study confirmed that patch testing may be useful for the selection of a suitable protein source for an elimination diet in dogs with suspected AFR, but not as a diagnostic tool for canine AFR. Results for proteins are more reliable than for carbohydrates and the majority of positive patch test reactions were observed with raw protein. Patch testing with commercial dog food does not seem to be useful.

Food Avoidance Diets for Dermatitis

Food allergy is relatively common in both children and adults, and its prevalence is increasing. Early exposure of food allergens onto skin with an impaired epidermal barrier predisposes to sensitization and prevents the development of oral tolerance. While immediate-type food allergies are well described, less is known about delayed-type food allergies manifesting as dermatitis. This is due, in part, to limitations with current diagnostic testing for delayed-type food allergy, including atopy patch testing. We conducted a systematic review of food avoidance diets in delayed-type food allergies manifesting as dermatitis. While beneficial in some clinical circumstances, avoidance diets should be used with caution in infants and children, as growth impairment and developmental delay may result. Ultimately, dermatitis is highly multifactorial and avoidance diets may not improve symptoms of delayed-type food allergy until combined with other targeted therapies, including restoring balance in the skin microbiome and re-establishing proper skin barrier function.

Role of atopy patch test for diagnosis of food allergy-related gastrointestinal symptoms in children

BACKGROUND

Double-blind, placebo-controlled food challenge is the gold standard for diagnosing food allergy. However, it is a time-consuming procedure and requires onsite medical supervision and resuscitating medicines and devices on hand. The objective of this study was to compare the atopy patch test (APT) with the oral food challenge test (OFC) in children with suspected food allergy-related gastrointestinal (GI) symptoms.

METHODS

A prospective self-controlled study enrolled children with a history of suspected food allergy-related GI symptoms. Skin prick test (SPT) and APT using lyophilized and commercial allergen extracts for cow's milk, egg, wheat, soy, and shrimp were evaluated, and OFC was performed.

RESULTS

Thirty-nine patients (25 boys, median age 2.4 yrs) with 76 events of suspected food allergy-related GI symptoms were enrolled. SPT was positive in 11/76 events (14.5%). Sensitivity, specificity, predictive values, and likelihood ratio were calculated related to the food challenge outcome. Of 41 OFC, 30 (73.2%) were positive. APT using lyophilized allergen extracts yielded high sensitivity (80%) and high positive predictive value (85.7%). APT using commercial allergen extracts yielded low sensitivity (30%) but high specificity (90%). The negative predictive value of APT using lyophilized and commercial allergen extracts was 53.8% and 32.2%, respectively. All cases with positive APT using lyophilized allergen extracts together with positive SPT also had positive OFC.

CONCLUSION

In contrast to commercial extracts, APT with lyophilized allergen extracts is reliable, safe, and maybe useful for the diagnosis of suspected food allergy-related GI symptoms in children. OFC is still needed in most of the cases.

Is it possible to make a diagnosis of raw, heated, and baked egg allergy in children using cutoffs? A systematic review

The diagnosis of IgE-mediated egg allergy lies both on a compatible clinical history and on the results of skin prick tests (SPTs) and IgEs levels. Both tests have good sensitivity but low specificity. For this reason, oral food challenge (OFC) is the ultimate gold standard for the diagnosis. The aim of this study was to systematically review the literature in order to identify, analyze, and synthesize the predictive value of SPT and specific IgEs both to egg white and to main egg allergens and to review the cutoffs suggested in the literature. A total of 37 articles were included in this systematic review. Studies were grouped according to the degree of cooking of the egg used for OFC, age, and type of allergen used to perform the allergy workup. In children <2 years, raw egg allergy seems very likely when SPTs with egg white extract are ≥4 mm or specific IgEs are ≥1.7 kUA /l. In children ≥2 years, OFC could be avoided when SPTs with egg white extract are ≥10 mm or prick by prick with egg white is ≥14 mm or specific IgE is ≥7.3 kUA /l. Likewise, heated egg allergy can be diagnosed if SPTs with egg white extract are >5 and >11 mm in children <2 and ≥2 years, respectively. Further and better-designed studies are needed to determine the remaining diagnostic cutoff of specific IgE and SPT for heated and baked egg allergy.

The Clinical Relevance of Various Hypersensitivity Tests in Patients with Atopic Dermatitis as Assessed by Their History, SCORAD Changes, and Number of Days with Need of Anti-Inflammatory Treatment

Immediate and delayed hypersensitivity reactions can play a role in the pathogenesis of atopic dermatitis (AD). We tested 71 patients (median age 5 years) with AD for hypersensitivity to grass and birch pollen, Dermatophagoides pteronyssinus, and Dermatophagoides farinae using atopy patch test (APT), skin prick test (SPT), and specific IgE measurement. The sensitivity (SE) and specificity (SP) of the tests were calculated on the basis of personal history of AD exacerbation, clinical AD score (SCORAD) changes, and the number of days with need for topical anti-inflammatory treatment (AITD) in relation to exposure to the allergens being tested. APT was positive in 45 patients, mostly to D. farinae (n=37). SPT and/or specific IgE were positive in 42 subjects, in most cases to grass and birch pollen (n=29). SE of APT reached 33%-56% for history, 33% for SCORAD, and 0%-60% for AITD; SP of APT was comparable for all three assessment standards (history, SCORAD, and AITD) (48%-67%). SE of SPT/specific IgE was higher for history (26%-63%) than for the other two standards of assessment (0%-67%); SP of SPT/specific IgE was also highest for history (69%-91%), and lower for SCORAD (59%-87%) and AITD (65%-80%). AD is often associated with hypersensitivity; its influence on AD, however, is clinically significant only in a minor group of patients. While personal history and SCORAD changes present themselves as possible standards in the evaluation of clinically relevant hypersensitivity in AD patients, the anti-inflammatory treatment days (AITD) appears to be unsuitable for this purpose.

Diagnostic Decision Points of Specific IgE Concentrations in Korean Children With Egg and Cow's Milk Allergies

Purpose

The purpose of this study was to evaluate the utility of specific IgE (sIgE) concentrations for the diagnosis of immediate-type egg and cow's milk (CM) allergies in Korean children and to determine the optimal cutoff levels.

Methods

In this prospective study, children ≥12 months of age with suspected egg or CM allergy were enrolled. Food allergy was diagnosed by an open oral food challenge (OFC) or through the presence of a convincing history after ingestion of egg or CM. The cutoff levels of sIgE for egg white (EW) and CM were determined by analyzing the receiver operating characteristic curves.

Results

Out of 273 children, 52 (19.0%) were confirmed to have egg allergy. CM allergy was found in 52 (23.1%) of 225 children. The EW-sIgE concentration indicating a positive predictive value (PPV) of >90% was 28.1 kU/L in children <24 months of age and 22.9 kU/L in those ≥24 months of age. For CM-sIgE, the concentration of 31.4 kU/L in children <24 months of age and 10.1 kU/L in those ≥24 months of age indicated a >90% PPV. EW-sIgE levels of 3.45 kU/L presented a negative predictive value (NPV) of 93.6% in children <24 months of age, while 1.80 kU/L in those ≥24 months of age presented a NPV of 99.2%. The CM-sIgE levels of 0.59 kU/L in children <24 months of age and 0.94 kU/L in those ≥24 months of age showed NPVs of 100% and 96.9%.

Conclusions

Our results indicate that different diagnostic decision points (DDPs) of sIgE levels should be used for the diagnosis of egg or CM allergy in Korean children. The data also suggest that DDPs with high PPV and high NPV are useful for determining whether OFC is required in children with suspected egg or CM allergy.

BSACI guideline for the diagnosis and management of cow's milk allergy

This guideline advises on the management of patients with cow's milk allergy. Cow's milk allergy presents in the first year of life with estimated population prevalence between 2% and 3%. The clinical manifestations of cow's milk allergy are very variable in type and severity making it the most difficult food allergy to diagnose. A careful age- and disease-specific history with relevant allergy tests including detection of milk-specific IgE (by skin prick test or serum assay), diagnostic elimination diet, and oral challenge will aid in diagnosis in most cases. Treatment is advice on cow's milk avoidance and suitable substitute milks. Cow's milk allergy often resolves. Reintroduction can be achieved by the graded exposure, either at home or supervised in hospital depending on severity, using a milk ladder. Where cow's milk allergy persists, novel treatment options may include oral tolerance induction, although most authors do not currently recommend it for routine clinical practice. Cow's milk allergy must be distinguished from primary lactose intolerance. This guideline was prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI) and is intended for clinicians in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking the panel of experts in the committee reached consensus. Grades of recommendation are shown throughout. The document encompasses epidemiology, natural history, clinical presentations, diagnosis, and treatment.

Patch testing for noncontact dermatitis: the atopy patch test for food and inhalants

The atopy patch test (APT) is defined as a patch test procedure to assess delayed type hypersensitivity reactions against those protein allergens known to elicit IgE-mediated type I reactions in atopic patients. This patch test procedure uses intact protein allergens instead of haptens in an optimized test setting and with a special reading key. It may be clinically useful especially for atopic dermatitis, as the currently available test procedures either target the wrong reaction type (type I and not type IV) or use the wrong allergens (haptens and not protein allergen). A positive APT reaction correlates with a positive lymphocyte transformation test and allergen-specific Th2 cells in the peripheral blood. As even small changes in the test procedure influence the sensitivity, specificity, and reproducibility of the APT, the European Task Force on Atopic Dermatitis (ETFAD) has developed a standardized APT technique: Intact protein allergens, purified in petrolatum, are applied in 12-mm-diameter Finn chambers mounted on Scanpor tape for 48 h to non-irritated, non-abraded, or tape-stripped skin of the upper back for 48 h; the evaluation of the test reaction is done after 48 and 72 h using the ETFAD reading key, assessing erythema as well as number and distribution pattern of the papules. The APT may reveal type IV sensitization in patients who are negative for the respective type I tests. Limited availability of the expensive test substances and limited reimbursement is among the factors restricting the routine use of the APT.

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.

Specific IgG and IgA of common foods in Chinese children with eczema: friend or foe

BACKGROUND

Specific immunoglobulins G and A (IgG and IgA) for common food items have been extensively measured as surrogate markers of food allergy, and dietary avoidance based on the test results advocated.

AIM

We reviewed the prevalence of specific food IgG and IgA in children with eczema and evaluated outcome of dietary avoidance in these children.

METHODS

Specific immunoglobulins of 96 food items were measured for 30 consecutive atopic dermatitis (AD) patients and disease severity [SCORing atopic dermatitis (SCORAD) and Nottingham eczema severity score (NESS)], Children Dermatology Life Quality Index (CDLQI), skin hydration (SH), transepidermal water loss (TEWL), topical corticosteroid and oral antihistamine usage were evaluated. Twenty seven of these patients received dietary avoidance advice based on IgG and IgA data. General acceptability of treatment (GAT) was documented at the end of 3 months.

RESULTS

There were generally no correlations among levels of IgG or IgA of the 96 food items and disease severity, quality of life, SH or TEWL. Two-third patients reported very good or good and one-third reported fair or poor GAT following dietary avoidance advice. There was no difference in any clinical parameters between the two groups following dietary avoidance. Patient with lower sunflower seed IgA (p = 0.043), casein IgG (p = 0.041), milk IgG (p = 0.037) or whey IgG (p = 0.014) had improved SCORAD and objective SCORAD following dietary advice.

CONCLUSION

Children with AD are sensitized to many food allergens via IgG and IgA mechanisms. Levels of food IgG or IgA do not seem to correlate with any clinical parameters in AD. Subjectively, two third of patients accepted dietary manipulations as very good or good for their AD. Objectively, dietary avoidance had few clinical effects on the clinical parameters. Sensitization should not be generalized to mean allergy to common food.

Food hypersensitivity in patients with childhood atopic dermatitis in Korea

Background

It is well known that atopic dermatitis (AD) is related to food hypersensitivity, although its prevalence varies among several studies according to age group, severity, country, survey time, and test method.

Objective

To examine the prevalence and status of food hypersensitivity among childhood AD patients in Korea.

Methods

A total of 95 patients were enrolled in the study. The history of food hypersensitivity was collected by interviews. The severity of AD was evaluated by eczema area and severity index (EASI). We took blood samples to measure serum total and food-specific immunoglobulin E (IgE) levels. Based on the histories and serum IgE levels, open oral food challenge (OFC) testing was performed to confirm food hypersensitivity.

Results

Forty-two (44.2%) of the 95 AD patients had histories of food hypersensitivity. They reported that the most common suspicious foods were egg (n=13, 13.7%), pork (n=9, 9.5%) and cow milk (n=8, 8.4%). The mean EASI score was 16.05±9.76. Thirty-nine (41.1%) of the 95 patients showed elevated serum food-specific IgE levels. The specific IgE levels were elevated for egg (n=17, 17.9%), milk (n=12, 12.6%), peanut (n=10, 10.5%) and wheat (n=8, 8.4%). Fifty-one (53.8%) of 95 patients underwent open OFC, and only 7 (13.7%) of these patients showed positive reactions.

Conclusion

The overall prevalence of food hypersensitivity in patients with childhood AD in Korea was 8.3% (7/84). The most common foods causing food hypersensitivity were egg and milk. Among the foods causing hypersensitivity, AD patients in Korea often underestimated peanut, while they overestimated pork.

The likelihood of remission of food allergy in children: when is the optimal time for challenge?

Although diagnostic testing methods for food hypersensitivity have improved over time, both in vivo and in vitro methods are significantly flawed, especially as evidenced by the frequent occurrence of false-positive test results. Because of these limitations, oral food challenge testing remains an essential element in the diagnosis and management of food allergy. In fact, the double-blind, placebo-controlled food challenge remains the gold standard for the diagnosis of food allergy. In this review, we focus on the optimal timing of oral food challenges, especially for patients with a known food allergy, to determine if the food allergy may have been outgrown.

The study of egg allergy in children with atopic dermatitis

CONTEXT

: Food allergy plays a significant pathogenic role among children with atopic dermatitis (AD).

OBJECTIVE

: The aims of this study were to evaluate allergy to egg in these children and determine the egg specific immunoglobulin E (IgE) cutoff point.

DESIGN AND SETTING

: It was a cross-sectional study that took place at Immunology, Asthma and Allergy Research Institute from 2005 to 2007.

METHODS

: Children younger than 14 years old with AD entered the study. Careful medical histories were taken and skin prick and Immuno-CAP tests with the most commonly offending foods (cow's milk, egg, wheat, peanut, and soy) were performed. Children with a clear, positive history of food allergy and a positive IgE-mediated test or those with positive responses to both IgE-mediated tests were determined to have food allergies. The egg-specific IgE level cutoff point was determined.

RESULTS

: A hundred patients entered the study (from 2 months to 12 years old). They were divided into 3 age groups: first <2 years, second from 2 to <6 years, and third from 6 to 14 years. The most common food allergens were egg (39.22%) in the first, cow's milk (35.13%) and egg (32.43%) in the second, and peanut (25%) and egg (16.67%) in the third group. The egg-specific IgE cutoff point value was 0.62 kUA/L (kilounits of allergen-specific IgE per liter). The positive predictive value was 95%.

CONCLUSION

: Prevalence of egg allergy is highly significant in patients with AD.To use egg-specific IgE level cutoff point, the patient population under study must be considered.

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.

Guidelines for treatment of atopic eczema (atopic dermatitis) part I

The existing evidence for treatment of atopic eczema (atopic dermatitis, AE) is evaluated using the national standard Appraisal of Guidelines Research and Evaluation. The consensus process consisted of a nominal group process and a DELPHI procedure. Management of AE must consider the individual symptomatic variability of the disease. Basic therapy is focused on hydrating topical treatment, and avoidance of specific and unspecific provocation factors. Anti-inflammatory treatment based on topical glucocorticosteroids and topical calcineurin inhibitors (TCI) is used for exacerbation management and more recently for proactive therapy in selected cases. Topical corticosteroids remain the mainstay of therapy, but the TCI tacrolimus and pimecrolimus are preferred in certain locations. Systemic immune-suppressive treatment is an option for severe refractory cases. Microbial colonization and superinfection may induce disease exacerbation and can justify additional antimicrobial treatment. Adjuvant therapy includes UV irradiation preferably with UVA1 wavelength or UVB 311 nm. Dietary recommendations should be specific and given only in diagnosed individual food allergy. Allergen-specific immunotherapy to aeroallergens may be useful in selected cases. Stress-induced exacerbations may make psychosomatic counselling recommendable. 'Eczema school' educational programs have been proven to be helpful. Pruritus is targeted with the majority of the recommended therapies, but some patients need additional antipruritic therapies.

A prediction rule for food challenge outcome in children

BACKGROUND

In children with food-related symptoms, a food challenge is considered as the gold standard to diagnose allergy. If food allergy could be predicted by patient history and/or diagnostic tests, the number of time-consuming and sometimes risky food challenges could be decreased. We aimed to determine questionnaire and test-based characteristics, to predict the food challenge outcome (FCO) in children referred to a tertiary centre for the evaluation of food-related symptoms.

METHODS

Pre-challenge standardized questionnaires, skin prick tests (SPT), and specific IgE levels (sIgE) were obtained in patients that underwent a food challenge in our hospital in 2009. Characteristics of patients with positive and negative FCO were compared, and uni- and multivariate associations between predictors and FCO were calculated. Based on the multivariate model, a risk score was developed to predict the FCO.

RESULTS

One hundred and twenty-nine challenges were analyzed, 41.9% had a positive outcome. Median age of both groups was 4.9 yrs (range 2.8-8.3). Patients with a positive FCO reacted faster with symptoms after allergen ingestion and had higher sIgE levels compared to children with negative FCO. A clinical risk score was developed based on the index food, 'time between allergen ingestion and complaints' and sIgE levels (range 0-10). The prognostic capacity of this model (AUC) was excellent (0.90). The very high- and low-risk groups (24% of patients) are both predicted excellent without misclassification.

CONCLUSION

Positive FCO can be predicted by the index food, time between allergen ingestion and development of symptoms, and the sIgE level.

Prediction of tolerance in children with IgE mediated cow's milk allergy by microarray profiling and chemometric approach

The sera of a retrospective cohort (n=41) composed of children with well characterized cow's milk allergy collected from multiple visits were analyzed using a protein microarray system measuring four classes of immunoglobulins. The frequency of the visits, age and gender distribution reflected real situation faced by the clinicians at a pediatric reference center for food allergy in São Paulo, Brazil. The profiling array results have shown that total IgG and IgA share similar specificity whilst IgM and in particular IgE are distantly related. The correlation of specificity of IgE and IgA is variable amongst the patients and this relationship cannot be used to predict atopy or the onset of tolerance to milk. The array profiling technique has corroborated the clinical selection criteria for this cohort albeit it clearly suggested that 4 out of the 41 patients might have allergies other than milk origin. There was also a good correlation between the array data and ImmunoCAP results, casein in particular. By using qualitative and quantitative multivariate analysis routines it was possible to produce validated statistical models to predict with reasonable accuracy the onset of tolerance to milk proteins. If expanded to larger study groups, the array profiling in combination with the multivariate techniques show potential to improve the prognostic of milk allergic patients.

Diagnostic value of hazelnut allergy tests including rCor a 1 spiking in double-blind challenged children

BACKGROUND

The diagnostic value of hazelnut allergy tests in double-blind challenged children is largely unknown. The aim of this study was to analyze the performance of current diagnostic tests for hazelnut allergy in children and the effect of spiking.

METHODS

Data of 151 children who underwent a double-blind placebo-controlled food challenge for hazelnut were analyzed. The positive predictive value and negative predictive value (PPV/NPV) of level of specific IgE (sIgE) for hazelnut, the influence of rCor a 1 spiking of the ImmunoCAP, and size of the skin prick test (SPT) for hazelnut were determined, also in relation to the severity of the hazelnut allergy. Reported accidental ingestion leading to an allergic reaction to hazelnut was also analyzed in relation to hazelnut allergy.

RESULTS

Specific IgE ≥0.35 kU(A) /l for hazelnut was a moderate predictor for hazelnut allergy. The spiking decreased the PPV from 41% to 38% and increased the NPV from 91% to 100% for sIgE ≥0.35 kU(A) /l. The maximum reached PPV was 73% for sIgE cutoff of 26 kU(A) /l. Level of sIgE before spiking was significantly different between different grades of severity and was lost after spiking. Skin prick test was a better predictor for hazelnut allergy and severity than the level of sIgE. A history of accidental ingestion leading to an allergic reaction to hazelnut had a predictive value of 59% for hazelnut allergy.

CONCLUSIONS

This study showed a good NPV of diagnostic tests for hazelnut allergy in children which further improved by rCor a 1 spiking. However, the PPVs are moderate and decreased by spiking.

Different clinical manifestation of cow's milk allergy in two preterm twins newborns

Adverse reactions to cow's milk in the first year of life occur in 2-7%. There is an increase in the incidence of cow's milk protein allergy (CMA) in newborn population including premature infants. We report two cases of CMA in preterm twins. The first one developed recurrent episodes of proctocolitis and the second one two necrotizing enterocolitis (NEC) -like episodes. Our cases demonstrate different clinical presentations of the same disease and add to literature the peculiarity of the early onset, the recurrence of episodes of enterocolitis associated with increasing systemic eosinophilia and episodes clinically and radiologically mimicking NEC.

Patch testing and allergen-specific serum IgE and IgG antibodies in the diagnosis of canine adverse food reactions

Adverse food reaction (AFR) is a common differential diagnosis for pruritic dogs. The only way to diagnose AFR is an elimination diet of 6-8 weeks with a protein and a carbohydrate source not previously fed. In humans, patch testing has been shown to be a useful tool to diagnose food allergies. In veterinary medicine, serum food allergen-specific antibody testing is widely offered to identify suitable ingredients for such diets. The aim of this study was to determine sensitivity, specificity, negative and positive predictability of patch testing with and serum antibody testing for a variety of common food stuffs. Twenty-five allergic dogs underwent an elimination diet and individual rechallenge with selected food stuffs, food patch testing and serum testing for food-antigen specific IgE and IgG. Eleven clinically normal control dogs only were subjected to patch and serum testing. The sensitivity and specificity of the patch test were 96.7 and 89.0% respectively, negative and positive predictability were 99.3 and 63.0%. For IgE and IgG the sensitivity was 6.7 and 26.7%, specificity were 91.4 and 88.3%, the negative predictive values 80.7 and 83.7% and the positive predictive values were 15.4 and 34.8%. Based on these results, a positive reaction of a dog on these tests is not very helpful, but a negative result indicates that this antigen is tolerated well. We conclude that patch testing (and to a lesser degree serum testing) can be helpful in choosing ingredients for an elimination diet in a dog with suspected AFR.

Development of a standardized low-dose double-blind placebo-controlled challenge vehicle for the EuroPrevall project

BACKGROUND

  Double-blind placebo-controlled food challenge (DBPCFC) is the gold standard for diagnosing food allergy. Standardized materials and protocols are essential for comparing DBPCFC results for multicentre studies such as EuroPrevall. This required the development and piloting of a standardized vehicle and low-dose protocol for confirming food allergy and determination of minimum eliciting doses (MEDs).

METHODS

  A low-dose DBPCFC protocol was developed, with eight titrated protein doses from 3 μg to 1 g. This was delivered using a simple, microbiologically stable food base incorporating allergenic food ingredients manufactured at three sites and centrally distributed to clinical centres. Allergen blinding was assessed by a professional sensory testing panel using a triangle test. Homogeneity and allergen content were confirmed by ELISA and clinical efficacy was assessed in a pilot study, using celeriac and hazelnut as exemplars.

RESULTS

  Celeriac and hazelnut ingredients were sufficiently blinded in the dessert. The dessert meals were successfully piloted with hazelnut in allergy clinics in Spain, the Netherlands and Italy and with celeriac and hazelnut in Zurich. The challenges elicited a range of subjective and objective reactions ranging in severity from mild itching of the oral mucosa to bronchospasm.

CONCLUSIONS

  A standardized challenge vehicle proven to sufficiently blind processed, powdered hazelnut and celeriac ingredients and that can be reproducibly manufactured has been developed. This pilot study shows that the vehicle is promising for the confirmation of food allergy and determination of MEDs in adults and children with body weight >28.8 kg (approximately 7-11 years old).

Importance of evaluating for cow's milk allergy in pediatric surgical patients with functional bowel symptoms

BACKGROUND

Cow's milk allergy (CMA) can cause functional bowel symptoms. This can lead to confusion and difficulty in managing pediatric surgical patients who also have CMA. We examined CMA's effect on the management of pediatric surgical patients in our institute.

METHODS

With institutional review board approval, 14 pediatric surgical patients with CMA were reviewed. Cow's milk allergy was diagnosed according to clinical findings and stimulation index (normal range <300%) of the lymphocyte stimulation test.

RESULTS

The main symptoms were abdominal distension (n = 10), vomiting (n = 6), constipation (n = 2), and apnea (n = 1). Stimulation index median value was 731% (range, 341%-2132%). Patients were divided into 3 groups. In group 1 (n = 8), persistent postoperative bowel symptoms were initially considered related to surgical diseases. Following CMA diagnosis, CM elimination therapy improved symptoms. In group 2 (n = 4), CMA was diagnosed concurrently with surgical disease, and elimination therapy was continued postoperatively. In group 3 (n = 2), the pathogenesis of bowel symptoms was initially attributed to CMA and later diagnosed as Hirschsprung's disease.

CONCLUSIONS

A high index of suspicion regarding the possibility of concurrent CMA may be necessary to manage bowel symptoms in pediatric surgical patients.

Molecular diagnosis of cow's milk allergy

PURPOSE OF REVIEW

To identify and discuss studies on the molecular diagnosis of cow's milk allergy (CMA) with a view to update allergists since a general review of the methodology in 2006.

RECENT FINDINGS

Seven basic research studies reporting the use of component-resolved diagnostics in CMA were found. All studies were on children positively reacting to a formal challenge with cow's milk. Six studies used natural allergens and three used recombinant milk proteins. Microarray platforms were customized and, thus, differed across studies. Three studies assessed the association between molecular-scale patterns and different presentations of the condition, that is the association between anaphylaxis, gastrointestinal symptoms and other severe phenotypes and the pattern of protein sensitization. Two studies assessed the association between positive oral food challenge and the persistence of milk allergy over time. Protein profiling could be useful to indicate appropriate specific immunotherapy.

SUMMARY

Accurate diagnosis of CMA is challenging and essential. The determination of the immunoglobulin E (IgE)-mediated response to sequenced and characterized allergens may be more useful in predicting the presence and severity of clinical allergy than the currently used skin or blood tests performed with whole extracts. However, as component recognition pattern heterogeneity is observed in different areas, further clinical studies are essential to correlate useful molecular diagnostics and biological markers with disease and patient profiles. Until such markers are found and validated in different age groups, oral food challenge remains the reference standard for the diagnosis of CMA.

Allergic proctocolitis refractory to maternal hypoallergenic diet in exclusively breast-fed infants: a clinical observation

Background

Allergic proctocolitis (APC) in exclusively breast-fed infants is caused by food proteins, deriving from maternal diet, transferred through lactation. In most cases a maternal cow milk-free diet leads to a prompt resolution of rectal bleeding, while in some patients a multiple food allergy can occur. The aim of this study was to assess whether the atopy patch test (APT) could be helpful to identify this subgroup of patients requiring to discontinue breast-feeding due to polisensitization. Additionally, we assessed the efficacy of an amino acid-based formula (AAF) when multiple food allergy is suspected. amino acid-based formula

Methods

We have prospectively enrolled 14 exclusively breast-fed infants with APC refractory to maternal allergen avoidance. The diagnosis was confirmed by endoscopy with biopsies. Skin prick tests and serum specific IgE for common foods, together with APTs for common foods plus breast milk, were performed. After a 1 month therapy of an AAF all patients underwent a follow-up rectosigmoidoscopy.

Results

Prick tests and serum specific IgE were negative. APTs were positive in 100% infants, with a multiple positivity in 50%. Sensitization was found for breast milk in 100%, cow's milk (50%), soy (28%), egg (21%), rice (14%), wheat (7%). Follow-up rectosigmoidoscopy confirmed the remission of APC in all infants.

Conclusions

These data suggest that APT might become a useful tool to identify subgroups of infants with multiple gastrointestinal food allergy involving a delayed immunogenic mechanism, with the aim to avoid unnecessary maternal dietary restrictions before discontinuing breast-feeding.