Allergic Rhinitis, Peanut Allergies
Conditions
Brief summary
Caucasian male and female participants age 18 years of age and older will be enrolled in this study if they have known birch or peanut allergies or known to be non-atopic. Participants will undergo skin testing to confirm their allergies if not completed in the last 12 months. Medications and medical history will be captured with a focus on atopic disorders. Participants will undergo birch and peanut patch testing to assess penetration and if potential correlation exists with filaggrin genotyping and phenotyping. Blood samples will be drawn from participants and DNA isolated for genotyping of null mutations in filaggrin.
Detailed description
Participants with confirmed history of birch induced allergic rhinitis or peanut allergy or that are non-atopic will undergo the following procedures. If not already completed in the previous year, participants will be skin tested to a panel of common environmental allergens, including birch pollen and peanut. To be considered non-atopic, all skin tests in the panel must be negative in the presence of a positive histamine control. All participants will also be skin tested to peanut, Arah 2, Ara h 8 (if obtainable), crushed raw unroasted peanut, peanut butter, peanut extract, Bet v 1 and birch pollen extract. Blood samples will be drawn for genotyping of the four most common null mutations in FLG in Caucasians (R501X, 2282del4, R2447X, S3247X). Patch testing will be performed using Ara h2, Arah8 (if obtainable), crushed raw unroasted peanut, peanut butter, peanut extract, Bet v 1 and birch pollen extract. Peanut and birch pollen allergens, both whole and components will be diluted 1:10 in both saline and petroleum jelly and applied to normal controls skin to establish levels for irritant reaction. If further dilutions are required to show non-irritation these will be performed. As well, a limited medical history and medication history will be documented, with a focus on atopic disorders (i.e. atopic dermatitis (eczema), allergic rhinitis, asthma, and food allergy). Those in the non-allergic control group will be excluded if they have features of eczema, food allergy or other atopic conditions). Medications that could potentially interfere with the skin test results (i.e. antihistamines) must be documented, and appropriate washout intervals observed prior to the skin test procedure, if necessary.
Interventions
None listed
Sponsors
Dr. Anne Ellis
Study design
Observational model
OTHER
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* caucasian male or females * participants 18 years of age and older * participants with known birch allergy, confirmed by a skin test 3mm or greater than the negative control * participants with diagnosed and confirmed peanut with allergy * confirmed by one of the following: * positive food challenge * convincing history of peanut allergy AND positive skin test (3mm \>= than negative control) OR peanut-specific IgE \>=0.35 * uncertain history of peanut allergy OR no exposure to peanut AND a positive skin test 5mm\>= negative control AND a peanut-specific IgE \>=15 * non-allergic controls who lack a diagnosis of any atopic diathesis and have supportive negative skin testing to a panel of common environmental allergens.
Exclusion criteria
* participants unable to complete study related procedures * participants that have taken or are taking restricted medications
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Peanut patch testing | Up to 17 months | Differences in patch test positive responses to peanut allergen (extract plus raw peanut butter preparations) between participants with confirmed peanut allergy, confirmed birch allergy and non-atopic controls. Responses are graded as: Negative (-) Irritant reaction (IR) Equivocal / uncertain (+/-) Weak positive (+) Strong positive (++) Very Strong Positive (+++) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Birch patch testing | Up to 17 months | Differences in patch test positive responses to birch allergen extract between participants with confirmed peanut allergy, confirmed birch allergy and non-atopic controls. Responses are graded as: Negative (-) Irritant reaction (IR) Equivocal / uncertain (+/-) Weak positive (+) Strong positive (++) Very Strong Positive (+++) |
Other
| Measure | Time frame | Description |
|---|---|---|
| Relationship of peanut and birch patch testing responses to filaggrin genotype | Up to 17 months | Presence or absence of positive patch tests to birch and peanut and correlation of these responses with filaggrin genotypes. |
Countries
Canada
Outcome results
None listed