Mixed Tree Nut Food Challenges

Mixed Tree Nut Food Challenges

The purpose of this prospective study is twofold: 1) to establish oral tolerance to selected tree nuts and to examine potential predictors of oral tolerance and 2) to determine the usefulness of mixed tree nut allergen food challenges in more efficiently defining tree nut allergy and oral tolerance.

To evaluate the absence of tree nuts (TN) allergy, referred patients from one of the Arkansas Children's Hospital (ACH) Allergy Clinic physicians with current serum immunoglobulin E (IgE) to TNs that meet eligibility criteria will be invited to undergo a series of open mixed TN food challenges.

A questionnaire pertaining to their TN allergy will be administered

A brief physical exam will be performed.

Skin prick tests using selected nut allergen extracts along with a positive (histamine) and a negative (salt-water) control will be performed at the first oral food challenge visit.

Each food challenges will be performed to 1 to 3 TNs.

Two telephone follow-up phone calls will evaluate inclusion/exclusion of tree nuts in the diet post food challenge.

Inclusion Criteria:

• Any patient between 3-21 years of age followed by the Allergy and Immunology Department at Arkansas Children's Hospital on tree nut avoidance diet.
• Has current serum IgE test within the past 12 months to major nuts in question. All TN serum IgE are <10
• Children must have a stable baseline examination prior to undergoing challenge without significant symptoms of atopic dermatitis, allergic rhinoconjunctivitis, current urticaria or other allergic symptoms deemed important by the physician.
• Children must have stable asthma and no wheezing or repetitive cough prior to challenge, nor have been treated with oral steroids for a significant asthma exacerbation within 1 month of challenge. Asthmatics that undergo lung function testing.
• Children must have no current illness (e.g., fever or viral illness) at time of challenge.
• The subject will be asked to restrict the use of antihistamines (short acting, 72 hours: long acting, 5-7 days), (B-agonists (12 hours), theophylline (12 hours), and cromolyn (12 hours) prior to the first mixed TN food challenge. Other medications may be continued.

Exclusion Criteria:

• Any TN serum IgE ≥10.
• Life-threatening reaction (respiratory involvement requiring medications, or shock, or gastrointestinal reaction requiring intravenous fluids) to any TN.
• History of a reaction in the past year or severe reaction in the past 2 years or a history of a severe reaction anytime with a TN serum IgE >5
• Unstable asthma, gastrointestinal disease, cardiovascular disease, chronic lung disease, beta-blocker use.