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While food hypersensitivity can be a life-threatening problem, its scope is yet to be fully developed. More work is needed to further define its parameters but basic food hypersensitivity has been significantly clarified in the decade of the 80's to become standard practice for most updated allergists. Studies related to inhalation of food antigens remains within the purview of research centers as does other immunologic processes. The diagnosis of food hypersensitivity remains dependent on the medical history with test like elimination diets, skin testing, and RAST. Double-blind, placebo-controlled, food challenges (DBPCFC) provide the most definitive support for the association between certain symptoms and a specific food.

Background: Atopic disease is an increasing problem. Eczema affects 10-20% of young children, and 33-37% of children with eczema are food allergic. Among other factors, nitric oxide (NO) is thought to play a role in eczema and food allergy. Following the atopic march, pproximately 80% of children with atopic eczema will become sensitized to aeroallergens and develop asthma and/or allergic rhinitis. Skin prick test is used for investigating sensitization and is considered a safe method. However, systemic allergic reactions may appear when the test is performed. In diagnosing food allergy and for evaluating achievement of tolerance, the oral food challenge is the method of choice, and the double-blind placebocontrolled fashion is 'the gold standard'. Skin prick test: We examined six cases of generalized allergic reactions in connection with skin prick testing in order to identify risk factors, and thereby increase safety, and we investigated the necessity of performing skin prick tests in duplicate. We found that all six children with generalized reactions were <6 months of age. When analyzing skin prick tests in duplicate, we found only 1.3% that showed diverging results, and in infants <6 months even fewer, 0.9%. Food challenge: We developed recipes and a protocol for low-dose oral food challenge to milk and egg to be used in young children outgrowing their food allergy so as to facilitate early re-/introduction of small amounts of milk and egg. We performed 52 challenges, both open and double-blind placebo controlled. The recipes were validated for blinding. The lowdose challenge was tolerated well by the children and was easy to perform. Four children had a positive challenge outcome, all reacting to very small amounts of milk. All but two of the non-reacting children were able to introduce milk and egg into their diet. Nitric oxide and eczema: We investigated the effect of eczema treatment on the NO levels in urine. The sum of nitrite and nitrate was measured in urinary samples from 94 infants at two visits, with an interval of 6 weeks, and the results were compared with clinical data. The levels of NO products increased significantly when the eczema improved. The atopic march: The aim was to evaluate the atopic march in children with eczema, from referral at <2 years until 4½ years of age. We followed 123 children with eczema, 78 sensitized and 45 not sensitized to milk and/or egg, with respect to eczema severity, other allergic manifestations, development of airway sensitization, and achievement of food tolerance. The difference in severity of eczema at referral was significant when comparing food-sensitized with non-sensitized children. At follow-up, 62% were still affected by eczema, although 56% only mildly so. Tolerance was achieved in 81% of the children allergic to milk and 68% of those allergic to egg. Fifty-eight percent of the food-sensitized children and 26% of the non-sensitized children had become sensitized to aeroallergens, a significant difference. The difference in airway symptoms was not significant. Very few children were exposed to tobacco smoke in their homes. Conclusions: Increased precautions should be considered when performing skin prick tests in infants <6 months of age. The use of a single prick, to avoid the risk of summation of reactions, is justified when performing skin prick tests. We report recipes and a protocol for standardized open and double-blind placebo-controlled low-dose food challenge in young children, enabling the introduction of small amounts of egg and milk into the diet during tolerance development. NO products in urine increases when eczema improves. This might be due to a Th2/Th1 shift induced by the eczema treatment and skin healing, and the variation in NO response may be due to individual variations in NO-induced feedback downregulation of Th1 and Th2 proliferation. The prognosis for achieving clinical tolerance is very good in children early sensitized and allergic to milk and egg, but they will become significantly more often sensitized to aeroallergens.

The Real Food Challenge (RFC) is a national student movement that is trying to harness student power to shift $1 billion'roughly 20% of college and university food budgets across the country towards local, ecologically sound, fair, and humane food sources, what they call "real" food, by 2020. The University of Vermont (UVM) was the fifth university in the country to sign the Real Food Campus Commitment, pledging to shift at least 20% of its own food budget towards "real" food by 2020. The purpose of this thesis is to evaluate the implementation of the Real Food Campus Commitment at UVM. In order to examine the demand for "real" food on the UVM campus I analyzed a survey of 904 undergraduate students that used contingent valuation to evaluate students' willingness-to-pay (WTP) for the "real" food attributes. I found that a majority of students are willing to pay a positive premium for "real" food, but that the average premium is quite small. Furthermore, I found that student characteristics and attitudes significantly influence WTP. Specifically, gender, residency, college, and attitudes about price and origin of food are significant predictors of WTP. To evaluate the potential of the RFC to significantly transform the food system I analyzed the activities and components of the RFC using the framework of food democracy. In addition to analyzing the activities and components of the RFC as a national movement, I analyzed the movement as it is being realized on the ground at UVM. My analysis reveals that the RFC has the potential to transform the food system because it promotes all five dimensions of food democracy as both a national movement and as realized on the ground at one university. Both of my analyses suggest that the RFC has significant potential to transform the food system at UVM, but that food systems education for the greater student body will crucial to see that potential fulfilled. This thesis can contribute to the success of the Real Food movement at UVM by identifying areas of weakness and opportunities for improvement in terms of increasing student preference for "real" food and promoting food democracy. Moreover, this thesis may be useful for national RFC staff and other campuses that are implementing the RFC, as it demonstrates how the RFC is being played out on the ground at an institution that is at the forefront of the movement.

Bakgrund: Eksem förekommer hos 10-20% av barn i hela världen. En tredjedel av barnen med eksem har födoämnesallergi. Hos de flesta växer födoämnesallergin bort innan skolåldern. Förbättrat kliniskt omhändertagande och bättre förståelse av hur klinisk tolerans uppkommer är viktiga mål för forskning inom barnmedicin. Studieupplägg: Denna doktorsavhandling baseras på studier av två grupper av barn. Den första är en stor grupp med misstänkt allergi som undersökts med pricktest vid ett tillfälle. Den andra gruppen består av små barn med eksem och misstänkt födoämnesallergi. Barnen påbörjade studien innan två års ålder och har sedan följts över tid till fyra och ett halvt års ålder. Säkerhet vid pricktest: 5908 barn med en medelålder på 6 år och 5 månader, undersöktes med pricktest (SPT). Sju barn (0,12 %) reagerade med generaliserad allergisk reaktion (GAR), och behövde antiallergisk medicinering. Sju barn reagerade vasovagalt (VVR) med svimning eller ”nära-svimning”. Riskfaktorer för GAR var ålder <1 år (RR 6,28) och aktivt eksem (RR 16,98). Risken för VVR var högst hos tonårsflickor och barn/ungdomar undersökta med många allergen (många prickar) samtidigt, oavsett om de var positiva eller inte. Effekt av lokalbehandling och födoämneselimination hos spädbarn med eksem: 123 barn, 52 flickor och 71 pojkar deltog i studien. Åldern varierade mellan 1-24 månader, med en medelålder på 8,4 månader vid studiens början. Kraven för att få delta var eksem och/eller misstänkt födoämnesallergi. Diagnos av eksem gjordes med stöd av Hanifin och Rajkas kriterier. Eksemgrad bedömdes med instrumentet SCORAD. Barnen bedömdes vid två tillfällen med ca sex veckors mellanrum. 62 % av barnen hade positiv pricktest för födoämnen. SCORAD-värdena i gruppen med positiv pricktest var högre än i gruppen med negativ pricktest, barnen som var födoämnessensibiliserade hade alltså svårare eksem. Efter sex veckors behandling; födoämneselimination+ lokalbehandling hos SPTpositiva barn; endast lokalbehandling hos SPT-negativa barn; var det ingen skillnad i eksemens svårighetsgrad mellan de två grupperna. Både födoämnessensibiliserade och icke födoämnessensibiliserade förbättrades signifikant av behandling. En grupp med negativ pricktest, men med påvisade antikroppar mot födoämnen i blodet (analyserade först i efterhand), som behandlades enbart med lokalbehandling förbättrade sina eksem lika mycket som de barn som också ställts på eliminationskost. Antikroppar i blod och saliv i relation till toleransutveckling: Serumnivåer av total- samt ägg- och mjölkspecifika antikroppar av IgE, IgG1 och IgG4 analyserades. I saliv analyserades totalnivåer av sekretoriskt IgA samt specifikt IgA mot mjölk och ägg. Prover togs vid studiens början, efter sex veckor samt vid 4,5 års ålder. Barn som var sensibiliserade mot mjölk och/eller ägg, men som tålde dessa födoämnen vid 4,5 års ålder hade högre IgG4 nivåer och högre IgG4/IgE-kvot vid studiens början, än de barn som ej uppnått tolerans. De högsta IgG4/IgE-kvoterna sågs hos barnen med negativt pricktest men positivt specifikt IgE i blod. Under den första korta observationsperioden på sex veckor sågs ingen påverkan på barnens antikroppsnivåer. Recept/metodutvecklande och resultat av öppna och dubbel-blinda placebokontrollerade födoämnesprovokationer: Efter recept och metodutveckling för födoämnesprovokationer med mjölk och ägg, utfördes 52 provokationer på 39 barn. Fyra barn, alla provocerade blint, reagerade på provokationen. Generella slutsatser: Risken för generaliserade allergiska reaktioner vid pricktest är liten hos barn och tonåringar, men den finns. Riskfaktorer är låg ålder och aktivt eksem. Vasovagala reaktioner är lika vanliga som generaliserade allergiska reaktioner. Lokalbehandling/smörjning ger signifikant förbättring av eksem. Elimination av födoämnen kanske inte är nödvändigt hos eksembarn med sensibilisering för mjölk och ägg under förutsättning att hudvården sköts noga. Höga IgG4/IgE-kvoter av specifika antikroppar mot födoämnen kan vara associerat med snabbare toleransutveckling, och kan stödja idén med fortsatt allergenexponering hos födoämnessensibiliserade barn. Recept på beredningar som väl maskerar komjölk och ägg, vid öppna och blindade födoämnesprovokationer, är en god hjälp vid provokationer av små barn som ofta är misstänksamma mot nya smaker och konsistenser av mat. / Background: Eczema affects at least 20 % of children worldwide, and 1/3 of them also have food allergy. In most children, the food allergy is temporary. Improved clinical management and better understanding of etiological mechanisms underlying the tolerance development are target issues in paediatric research. Study design: The thesis is based on two study groups. The first is a large group of children with suspected allergy investigated with skin prick test in a cross-sectional study. The second group is a cohort of infants with eczema and/or suspected food allergy before 2 years of age, investigated prospectively with follow-up to 4.5 years of age. Safety of skin prick test (SPT): 5908 children with a mean age of 6.4 years (range: 1 month – 18 years) were investigated with SPT. Seven children, i.e. 0.12%, displayed a generalized allergic reaction (GAR), necessitating pharmacological treatment. Seven children showed a vasovagal reaction (VVR). Risk factors for GAR were age < 1 year (RR 6.28) and eczema (RR 16.98). The risk for VVR was highest among female adolescents, and children investigated with multiple skin pricks. The effect of skin care and food elimination on eczema in infants: 123 children, 52 girls and 71 boys, with a mean age of 8.4 months (range: 1-24 months) were recruited due to eczema and/or suspected food allergy. For diagnosis of eczema, the Hanifin and Rajka criteria were used, and for scoring of eczema severity SCORAD. The infants were investigated twice with an interval of 6 weeks. 62% showed positive SPTs. The SCORAD was higher among the sensitized children before treatment compared to not sensitized children. After treatment, i.e. skin care for all and elimination diet for sensitized children, there was no difference regarding eczema severity. Both SPT-positive and SPT-negative children decreased their SCORAD values significantly after treatment. A SPT-negative subgroup, with circulating specific IgE to milk/egg, was only treated with skin care, but these children improved their eczema to the same extent as those also treated with an elimination diet. Serum and salivary antibodies and achievement of tolerance Analyses were performed regarding: serum levels of total and egg- and milk-specific IgE antibodies, IgG1 and IgG4 antibodies to β-lactoglobulin (BLG) and ovalbumin (OVA); and salivary levels of total IgA, total SIgA and salivary IgA antibodies to OVA and BLG. Samples were drawn at inclusion, after 6 weeks of intervention (skin care, elimination diet), and at 4.5 years of age. Children sensitized to egg and/or milk who had developed tolerance at 4 ½ years of age had higher levels of IgG4 antibodies to OVA and BLG and also higher IgG4/IgE ratios on inclusion in the study, than those who remained non-tolerant. The highest IgG4/IgE ratios were found in children with circulating IgE antibodies to egg and/or milk but negative SPT on inclusion. The six-week treatment period did not significantly affect the levels of serum and salivary antibodies. Recipes and outcomes of open and double-blinded food challenges in children: After development of recipes for open and blinded challenge with cow’s milk and egg, 52 challenges were performed in 39 children. 4 children, challenged blindly, had a positive outcome of the challenge. General conclusions: The risk for generalized allergic reactions at SPT is low among children and teenagers, but allergic reactions do occur, and low age and eczema are risk factors. Vasovagal reactions occur as often as allergic reactions. Skin care gives significant improvement of eczema severity. Elimination diet may not be needed in infants with sensitization to milk and/or egg, provided that the skin care is adequate. High ratios of serum IgG4/IgE antibodies to food allergens may be associated with faster achievement of clinical tolerance, and may support the concept of benefit from continuing allergen exposure in sensitized children. Recipes for masking of cow’s milk and egg in open or blinded food challenges may help to accomplish challenges in young children, often suspicious to unfamiliar tastes or textures.