Eczematous reactions to food in atopic eczema: position paper of the EAACI and GA2LEN

Food allergy and atopic eczema (AE) may occur in the same patient. Besides typical immediate types of allergic reactions (i.e. noneczematous reactions) which are observed in patients suffering from AE, it is clear that foods, such as cow's milk and hen's eggs, can directly provoke flares of AE, particularly in sensitized infants. In general, inhaled allergens and pollen-related foods are of greater importance in older children, adolescents and adults. Clinical studies have revealed that more than 50% of affected children with AE that can be exacerbated by certain foods will react with a worsening of skin eczema either alone or in addition to immediate symptoms. Adolescents and adults may also react to foods, but reactions to 'classical' food allergens, such as hen's eggs and cow's milk, are not as common as in childhood. Some patients with AE do react to pollen-associated foods. Food-induced eczema should not be neglected by the allergologist: On the one hand, food can be a relevant trigger factor of persistent moderate-to-severe AE; on the other hand, unnecessary diets which are not based on a proper diagnosis may lead to malnutrition and additional psychological stress on patients suffering from AE. Eczematous reactions to food can only be diagnosed by a thorough diagnostic procedure, taking into account the patient's history, the degree of sensitization and the clinical relevance of the sensitization. The latter has often to be proven by oral food challenges. Upon oral food challenge it is most important to evaluate the status of the skin with an established score (e.g. SCORAD, EASI) after 24 h and later because otherwise worsening of eczema will be missed.

[Atopic dermatitis and food allergies]

Around 13% of children in Switzerland are affected by atopic dermatitis. Cutaneous defects with increased water loss and allergens permeability are hallmark of the disease. The prevalence of food allergy in children with moderate-to-severe atopic dermatitis is estimated to be 34%, mostly to eggs, milk and peanuts. Food allergy can cause immediate reactions with urticaria and anaphylaxis or delayed flares of eczema. In older patients and adults, exposition to respiratory allergens (dust mites, pollen) can also cause an exacerbation of the eczema. Allergy testing identifies patients with atopy, who are at greater risk of rhinitis and asthma. Skin prick tests, in vitro tests and food challenges can identify a concomitant allergy, leading to specific allergen avoidance mea-sures potentially improving skin symptoms.

Trends in prevalence of asthma, allergic rhinitis and atopic dermatitis in 5-7-year old Swiss children from 1992 to 2001

BACKGROUND

Changing occurrence rates of asthma, allergic rhinitis and atopic dermatitis are of public health concern and require surveillance. Changes in prevalence rates of these atopic diseases were monitored during 10 years and their trend with time was determined taking into account the influence of personal and environmental risk factors.

METHODS

Four cross-sectional surveys in 5-7-year old children were performed in seven different communities in Switzerland between 1992 and 2001. Prevalence of respiratory and allergic symptoms and of affecting risk factors including parental environmental concern were assessed using a standardized parental questionnaire.

RESULTS

A total of 988 (74.1%), 1778 (79.0%), 1406 (82.6%) and 1274 (78.9%) children participated, respectively, in the 1992, 1995, 1998 and 2001 surveys. Prevalence rates of asthma and hay fever symptoms remained quite stable over time (wheeze/past year: 8.8%, 7.8%, 6.4% and 7.4%, sneezing attack during pollen season: 5.0%, 5.6%, 5.4% and 4.6%). Rates of reported atopic dermatitis symptoms (specific skin rash/past year: 4.6%, 6.5%,7.4% and 7.6%) showed an increase over time, but those of diagnosis of eczema did not show a clear pattern (18.4%, 15.7%, 14.0% and 15.2%). Stratified analysis by parental environmental concern and by parental atopy showed similar trends. Rates of atopic dermatitis symptoms showed significant increase in girls but stayed stable in boys.

CONCLUSION

Results of these four consecutive surveys suggest that the increase in prevalence of asthma and hay fever in 5-7-year old children living in Switzerland may have ceased. However, symptoms of atopic dermatitis may still be on the rise, especially among girls.

Diagnosis of allergy syndromes: do symptoms always mean allergy?

Allergic disease has become a major burden in westernized societies because of a recent rise in its prevalence. Approximately one-third of children suffer from an allergic disease, with the prevalence varying from 15 to 20% for atopic dermatitis, 7 to 10% for asthma and 15 to 20% for allergic rhinitis and conjunctivitis. Despite the increase, it is important not to assume a diagnosis of allergy on the basis of symptoms alone, because allergic and nonallergic conditions may present with similar symptoms. An accurate allergy diagnosis is important in order to treat the patient most appropriately and to potentially prevent or delay the development of allergic disease. A good clinical history is the starting point for accurate allergy diagnosis but is not unequivocal. The European Academy of Allergy and Clinical Immunology has recognized the importance of allergy testing and therefore developed evidence-based recommendations on allergy testing in children. Widespread adherence to these recommendations should improve the quality of care for allergy patients. Cooperation between all healthcare professionals involved in the treatment of allergy patients is also a key to improve our response to the allergy epidemic.

[Treatment of atopic dermatitis: practical approach]

Atopic dermatitis (AD) is a chronic disease frequent in childhood. The treatment is based on regular moisturizing of the skin, information to the parents on the chronic course with recurrent flares, topical anti-infectious therapy for superinfections and colonization of the skin by staphylococcus aureus, and topical steroids. The immuno-modulatory macrolides (tacrolimus and pimecrolimus) represent a new alternative to topical steroids. These molecules are well tolerated, but theirs effects on the long-term are unknown. A food allergy may be responsible for a AD flare in up to a third of the cases, but the presence of an allergy should be demonstrated before the prescription of an elimination diet. AD is often the first manifestation of atopy: the physician should be aware of the future occurence of respiratory symptoms.

Breast-feeding and atopic eczema dermatitis syndrome: protective or harmful?

Numerous studies have addressed the potential of breast-feeding to protect for the development of allergic diseases, and in particular of atopic eczema dermatitis syndrome (AEDS). Although the majority of studies, as well as several meta-analyses, are strongly in favour of breast-feeding, there are some conflicting results and open issues. Furthermore, breast-feeding might be detrimental in a subgroup of young infants with severe early manifestations of AEDS and immunoglobulin E sensitizations to common foods. The aim of this review is not to analyse systematically the current literature, but to suggest a scientifically and clinically based analysis of the benefits of breast-feeding in atopic infants.

A consensus protocol for the determination of the threshold doses for allergenic foods: how much is too much?

BACKGROUND

While the ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies, little information is known regarding these threshold doses for specific allergenic foods. While low-dose challenge trials have been conducted on an appreciable number of allergic individuals, a variety of different clinical protocols were used making the estimation of the threshold dose very difficult.

OBJECTIVE

A roundtable conference was convened to develop a consensus clinical protocol for low-dose challenge trials for the estimation of threshold doses for specific allergenic foods.

METHODS

In May 2002, 20 clinical allergists and other interested parties were invited to participate in a roundtable conference to develop consensus of the key elements of a clinical protocol for low-dose challenge trials.

RESULTS

A consensus protocol was developed. Patients with convincing histories of food allergies and supporting diagnostic evidence including past challenge trials or high CAP-RAST scores can be enrolled in low-dose challenge trials. Care must be taken with younger patients to assure that they have not outgrown their food allergy. An approach was developed for the medication status of patients entering such trials. Challenge materials must be standardized, for example, partially defatted peanut flour composed of equal amounts of the three major varieties of peanuts (Florunner, Virginia, Spanish). Challenge materials must be appropriately blinded with sensory evaluation used to confirm the adequacy of blinding. A double-blind, placebo-controlled design should be used for low-dose challenge trials. Low-dose challenge trials would begin at doses of 10 microg of the allergenic food and would continue with doses of 100 microg and 1 mg followed by specific higher doses up to 100 mg depending upon the expert judgement of the physician; even higher doses might be applied to assure that the patient is indeed reactive to the particular food. A 30-min time interval would be used between doses, and reactive doses would be expressed as both discrete and cumulative doses. The goal of each challenge would be to develop objective symptoms; trials should not be discontinued on the basis of subjective symptoms only. Statistically, a minimum of 29 patients would be enrolled in low-dose challenge trials for each allergenic food because 0 reactors out of 29 patients at a particular dose allow the conclusion that there is 95% certainty that 90% of allergic individuals will not react to that dose.

CONCLUSION

A consensus protocol was developed. Using this protocol, it will be possible to estimate threshold doses for allergenic foods, the lowest amount that elicits mild, objective symptoms in highly sensitive individuals.

Future therapeutic options in food allergy

Up to 5% of young children and 2% of adults suffer from food allergy. Among them many have immunoglobulin E (IgE)-mediated food allergy, a condition with potentially fatal allergic reactions. Several studies have addressed possible definite treatment options for food allergy. Immunotherapy, by the oral route or by systemic injections shows promising preliminary results, but current interpretation of these therapeutic options are mostly handicapped by studies with insufficient scientific support, or by severe side-effects. Currently, no studies can support pharmacotherapy. Finally, most promising results were recently published with anti-IgE antibodies in a human trial, or various approaches in a mouse model of food allergy (chinese herbal medicine, specific modulation of the T cell response). Rapidly evolving findings might provide hope for a cure of food allergy in the near future.

An internet-based survey on the circumstances of food-induced reactions following the diagnosis of IgE-mediated food allergy

BACKGROUND

Despite careful avoidance measures, food allergic patients have a significant risk of anaphylactic episodes. Risk situations need to be identified for more efficient preventive measures.

METHODS

Responders to an internet-based survey on the awareness of food anaphylaxis were invited to relate the circumstances of their most severe reaction following the diagnosis of IgE-mediated food allergy. Items of the questionnaire included the circumstances of the reaction and the treatment, as well as questions related to reactions occurring at specific categories of sites (i.e. home, schools, or restaurants).

RESULTS

Fifty-one of the returned questionnaires (34.1%) corresponded to the study criteria. The median age of the subjects was 7 years (range 0.5-61), with 33/51 (64.7%) being less than 16 years of age. Reactions were reported to peanuts (24/51; 47.1%), milk (12/51; 23.5%), tree nuts (6/51; 11.8%), fish and shellfish (5/51; 9.8%), and others (3/51; 5.8%). Reactions occurred at home (13/51; 25.5%), in restaurants (9/51; 17.6%), at school or daycare or kindergarten (8/51; 15.7%), at a relative or friend's home (7/51; 13.7%), at sites of leisure activities (6/51; 11.8%), at work (3/51; 5.9%), in church or a hospital ward (2/51; 3.9% each), or in a food store (1/51; 2.0%). In severe reactions (37/51; 72.5%) epinephrine was administered in 28/37 (75.7%) of the responders. Finally, while most reactions happened after ingestion of the food (40/51; 78.4%), others were reported after skin contact exclusively (8/51; 16%), or after inhalation (3/51; 5.9%).

CONCLUSION

Food induced-anaphylaxis in patients aware of their allergy happens most often at sites considered as safe (i.e. home, schools, workplace, hospitals). Better strategies to avoid accidental reactions include clear labelling of forbidden foods and increased information at all levels. These might dramatically reduce the risk of food-induced anaphylaxis in food allergy sufferers.

An Internet-based survey of anaphylactic reactions to foods

BACKGROUND

A favorable outcome of anaphylaxis depends on the rapidity of adequate initial management and epinephrine injection. However, few data on the management of anaphylactic reactions are available. The aim of this study was to investigate the management and awareness of anaphylaxis to foods by mean of an Internet-based survey.

METHODS

Visitors to a website with information on food allergy were invited to join the survey. Items in the survey included the management of anaphylactic reactions, investigations done by the diagnosing physician, and information given to the responder in anticipation of a new anaphylactic reaction.

RESULTS

Almost all of the 264 responders were from North America, Europe, Australia, or New Zealand (263/264). The most recent reaction was treated by epinephrine injection in 68.7% (180/262) of cases, or by antihistamines in 14.1% (37/262). Epinephrine was the first treatment for the most severe reaction in only 43.9% (101/230), while antihistamines were given first in 43.5% (100/230). One-third (62/210 = 29.5%) of the responders diagnosed by a physician received neither a diagnostic blood test nor a skin test. Responders diagnosed by an allergist were more often investigated (91/105 = 86.7%) than those diagnosed by a pediatrician or an internist (29/44 = 65.9%), a general practitioner (22/45 = 48.9%), or another physician (6/16 = 37.5%) (P < 0.001). Most responders had received instructions on how to deal with a new episode of anaphylaxis (244/263 = 92.8%). Responders instructed by an allergist were most frequently satisfied with the instructions (115/131 = 87.8%).

CONCLUSION

A large number of responders did not receive epinephrine for treatment of their most severe, or most recent anaphylactic reaction, and did not undergo allergy tests. The conventional management of anaphylaxis might still be improved.

Oral carrageenan induces antigen-dependent oral tolerance: prevention of anaphylaxis and induction of lymphocyte anergy in a murine model of food allergy

Immunosuppressive effects of carrageenan, a high-molecular-weight polysaccharide, on antibody and T cell responses have been previously demonstrated. However, its effect on anaphylaxis is unknown. Our objectives were to test carrageenan-mediated oral tolerance induction in young mice subsequently sensitized to a common cow's milk antigen. C3H/HeJ mice were fed or not lambda-carrageenan (0.5 g/L) and/or 0.01 mg/mL beta-lactoglobulin (BLG) for 5 d before oral sensitization with BLG and cholera toxin. Subsequently, the mice were challenged with BLG and symptom scores of anaphylaxis were recorded. Mesenteric lymph node cells, spleen cells, Peyer's patches cells, intraepithelial lymphocytes, and lamina propria lymphocytes were isolated and stimulated in vitro with BLG, IL-2, or left unstimulated. BLG-specific IgG, IgG(1), and IgG(2a) antibodies were measured. Pretreatment with carrageenan and BLG, but not pretreatment with either carrageenan or BLG alone or omission of pretreatment, diminished significantly the number of anaphylactic mice after BLG challenge (6.3 % versus 53 % in mice without pretreatment, p = 0.006). Mesenteric lymph nodes and spleen cells from pretreated mice proliferated less in presence of BLG or IL-2 than cells from sensitized control mice. Antigen-specific antibody production and passive cutaneous anaphylaxis was not suppressed by carrageenan and BLG pretreatment. In conclusion, carrageenan administered to young mice in conjunction with low doses of allergen before sensitization efficiently prevents anaphylaxis.

Ethanol-induced urticaria: elevated tryptase levels after double-blind, placebo-controlled challenge

We present a 48-year-old patient who complained for 1 year about urticarial reactions which appeared always when he ingested alcoholic beverages. Skin prick tests with ethanol were negative but positive with 10% acetic acid in the patient. Normal controls tested negative with acetic acid. Skin prick tests to common immediate-type allergens were negative. The patient underwent a double-blind, placebo-controlled challenge test. A few minutes after challenge with ethanol but not with placebo, the patient developed erythema and wheals on the chest and the upper arms. The tryptase serum level rose from undetectable (0.1 U/ml) before challenge to 3.8 U/ml after skin lesions had appeared. This case demonstrates that increased tryptase serum levels can help in the diagnosis of ethanol-induced urticaria.

Diagnosis of IgE-mediated food allergy among Swiss children with atopic dermatitis

Diagnosis of food allergy in children with atopic dermatitis (AD) relies on a good knowledge of the prevalence of the disease and of the foods most frequently involved. Our objective was to define these characteristics in a population-of Swiss children with AD. Patients referred to a pediatric allergist or a dermatologist for AD were routinely tested by skin-prick test (SPT) to seven common food allergens (milk, egg, peanut, wheat, soy, fish, and nuts), and to all other foods suspected by history. Patients with positive SPTs were further evaluated for specific serum immunoglobulin E (IgE) antibodies (by using the CAP System FEIA ). CAP values were interpreted following previously published predictive values for clinical reactivity. Patients with inconclusive results (between the 95% negative predictive value [NPV] and the 95% positive predictive value [PPV]) were challenged with the suspected food. A total of 74 children with AD were screened for food allergies. Negative SPTs excluded the diagnosis in 30 subjects. Nineteen patients were diagnosed by histories suggestive of recent anaphylactic reactions to foods and/or CAP values above the 95% PPV. Forty-three food challenges (35 open challenges and eight double-blind, placebo-controlled in children with persistent lesions of AD despite aggressive topical skin treatment) were performed in patients with positive SPTs but with inconclusive CAP values. Six patients were diagnosed as positive to 15 foods. Challenges were not performed to high-allergenic foods in young children (under 12 months of age for egg and fish, and under 3 years of age for peanuts and nuts). Altogether, 33.8% (25 of 74) of the AD patients were diagnosed with food allergy. The prevalence of food allergy was 27% (seven of 25) in the group referred to the dermatologist for primary care of AD. The foods most frequently incriminated were egg, milk, and peanuts. The prevalence of food allergy in our population was comparable to that in other westernized countries, suggesting an incidence of food allergy in approximately one-third of children with persistent lesions of AD. Together with milk and eggs, peanuts were most frequently involved in allergic reactions.

Allergenicity of major cow's milk and peanut proteins determined by IgE and IgG immunoblotting

BACKGROUND

Specific IgG antibodies are frequently observed in food-allergic patients. However, the allergen-fraction specificity of IgG antibodies in relation to IgE antibodies is not well defined. Our aim was to determine the IgE and IgG antibody profile to major cow's milk and peanut-antigen fractions in food-allergic patients and tolerant individuals.

METHODS

Sera were collected from 10 patients allergic to cow's milk and 10 patients allergic to peanuts, as well as from 20 control subjects. Cow's milk and peanut proteins were migrated on SDS-PAGE and immunoblotted for IgE, IgG, and IgG4 antibodies. Food-specific IgE concentrations were measured by CAP System FEIA, and IgG and IgG4 concentrations by ELISA.

RESULTS

In food-allergic children, similar fraction-specific IgE, IgG, and IgG4 antibody-binding profiles to the major cow's milk or peanut antigens were found. In nonallergics, the presence of fraction-specific IgG antibodies was mostly dependent on regular ingestion of the food. The presence of specific antibody on immunoblots correlated with their quantitative measurement. The mean value for specific IgE in cow's milk-allergic patients was 450 +/- 1,326 IU/ml, and 337 +/- 423 IU/ml in peanut-allergic patients. Specific IgG antibody values in milk-allergic patients were not different (median OD 1.5, range 0.3-2.3) from controls (median OD 1, range 0.2-1.8). However, in peanut-allergic patients, IgG concentrations were significantly higher than in controls (OD 1.2 [0.5-1.3] vs 0.5 [0.3-0.7]; P< 0.01).

CONCLUSIONS

Similar fraction-specific IgE and IgG antibody profiles in allergic individuals suggest a common switching trigger involving both isotypes. Intrinsic allergenicity might explain identical IgG antibody fraction specificity in nonallergics and in allergics. The presence of IgG antibodies in nonallergics was related to regular ingestion of the food.

The mucosal adhesion receptor alpha4beta7 integrin is selectively increased in lymphocytes stimulated with beta-lactoglobulin in children allergic to cow's milk

BACKGROUND

It has been shown in mice that the integrin alpha4beta7 directs the migration of memory T cells into the gut-associated lymphoid tissue. However, little is known about T-cell homing mechanisms in children with food allergies.

OBJECTIVE

We investigated the expression of this and other integrins in children with different manifestations of cow's milk allergy (urticaria, atopic dermatitis, and wheezing).

METHODS

PBMCs were stimulated with beta-lactoglobulin, 1 of the major allergenic proteins in cow's milk, and tetanus toxoid. Integrin expression was studied by flow cytometric analysis after 1 week of culture.

RESULTS

We found significantly higher expression of the alpha4beta7 integrin in cells from patients compared with control subjects with no allergies (P =. 005) when beta-lactoglobulin was used to stimulate the cells. alpha4beta7 integrin was also expressed at significantly higher levels in beta-lactoglobulin-stimulated cells than in tetanus toxoid-stimulated cells (P =.005). The alphaEbeta7 and the alpha4beta1 integrins were not upregulated by allergen stimulation. Most alpha4beta7 integrin-expressing cells were identified as CD4(+) T cells.

CONCLUSION

These results show that alpha4beta7 integrin expression after stimulation with beta-lactoglobulin correlates with the presumptive site of cow's milk sensitization (ie, the gut-associated lymphoid tissue but not with the site of symptoms of cow's milk allergy).