Tree Nuts Allergies: Does a Single Nut Allergy Necessitate the Dietary Eviction of Other Tree Nuts?
Condition: Nut Allergy in Children
MeSH terms: Hypersensitivity; Nut Hypersensitivity
Study type: Interventional

Summary: 
      The aim of this study is to identify, based on standardized food provocation tests, which
      nuts allergic patients need a selective, or a complete dietary eviction of all kind of nuts
      (nuts being defined as peanut, all tree nuts, pine nut and sesame). The investigators
      postulate that predictive factors of multiple nut allergy are high specific immunoglobulin E
      level, positive skin tests and/or clinical markers, such as atopic dermatitis, presence of
      other food allergies or a history of a severe previous reaction
    

Detailed description: 
      Food allergy in children is a disease of growing importance, current estimation in school age
      children are between 4 and 8 %. The most frequently involved foods in IgE reaction in
      school-aged children are hazelnut (especially in Switzerland according to the ongoing Swiss
      Registry, Wiesner et al, personal communication) and peanut. Tree nuts and peanut allergies
      are often involved in severe reactions, including cases of death by anaphylaxis. In addition,
      the disease is long-lasting as Fleischer et al could show that only 9% of children with nut
      allergies will outgrew from it. This number is worse than for peanut where a positive outcome
      is seen in 20% of the patients.

      Food challenges are the most reliable tests to investigate a possible food allergy, but these
      are time consuming and may elicit severe reactions in patients with a previous history of
      anaphylactic reactions(8). There are no allergy tests able at this time to predict with
      certainty the clinical reactivity, although Sampson et al could identify a general tree nuts
      specific IgE cut-off level with a high positive predictive value for clinical reactivity.

      It could be demonstrated, in well-designed studies, that in vitro cross-sensitivity between
      tree nuts (members of the oleaginous family) and peanut (members of the legume family) is
      frequent (86%). However, clinical reactions to tree nuts are estimated to be present in only
      40% of peanut allergic patients. Therefore 60% of peanut allergic patients may eat tree nuts
      without reactions.

      Similarly, there is a large in vitro cross-sensitivity between tree nuts. However, it is not
      known to date if this cross-sensitivity relates to clinical reactivity. Consequently, in case
      of one tree nut allergy, strict eviction to all nuts is largely recommended, and possibly
      results in a unnecessary dietary eviction of all tree nuts leading to a high impact on the
      quality of life of the children.

      We aim to identify, based on standardized food provocation tests, which nuts allergic
      patients need a selective, or a complete dietary eviction of all kind of nuts (nuts being
      defined as peanut, all tree nuts, pine nut and sesame). We postulate that predictive factors
      of multiple nut allergy are high specific immunoglobulin E level, positive skin tests and/or
      clinical markers, such as atopic dermatitis, presence of other food allergies or a history of
      a severe previous reaction.
    

Intervention name(s): Oral food challenges to multiple nuts
Intervention type(s): Other
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Nuts; allergy; Oral food challenge; skin testing; basophil activation tests; specific IgE's