Peanut, tree nut, and pollen: Better peanut allergy risk assessment when testing with allergen components
Rudi, an 8-year old boy with a history of rhino-conjunctivitis during tree pollen season and asthma exacerbations during infections and exertion, sees his healthcare provider because he is now also experiencing itching in the mouth when eating hazelnuts. His mother is sensitized to tree nuts and is worried that Rudi is, too.
His healthcare provider conducts a full clinical history and physical examination and decides to test using specific IgE testing.
See how specific IgE blood testing helped Rudi determine his risk of severe reaction to peanut and tree nuts.
Patient History
Family History
- Mother, allergic to tree nuts.
- Younger brother, allergic to egg, milk, peanut, tree pollen, cat, and dog.
Rudi’s Personal History
- Rudi had eczema from 6 months of age until he started school.
- Asthma attacks during infections and exertion.
- Rhino-conjunctivitis during tree pollen season.
Test |
Type |
Rudi’s Results |
Birch |
Whole Allergen |
+3 |
Peanut |
Whole Allergen |
+4 |
Hazelnut |
Whole Allergent |
+1 |
Cat |
Whole Allergent |
+4 |
Dog |
Whole Allergen |
+1 |
Clinical diagnosis
Tree pollen, peanut, tree nut, and pet dander allergy.
Based on history, evaluation, and testing, his previous healthcare provider recommended that Rudi strictly avoid peanut and tree nuts and use oral antihistamines during tree pollen season, as well as symptomatic treatment with inhalant long-acting ß2-agonists and corticosteroids.
Rudi’s ImmunoCAP™ Test Results
These results, together with Rudi’s case history and symptoms, may help his healthcare provider confirm the diagnosis.
Test |
Type |
Rudi’s Results |
Birch |
Whole Allergen |
23.1 |
Peanut |
Whole Allergen |
7.3 |
Hazelnut |
Whole Allergen |
12.4 |
Cat |
Whole Allergen |
10.2 |
Dog |
Whole Allergen |
4.2 |
Based on these results you decide to perform testing with allergen components.
Test |
Type |
Rudi’s Results |
Ara h 1 |
Allergen Component |
0.2 |
Ara h 2 |
Allergen Component |
4.3 |
Ara h 3 |
Allergen Component |
<0.1 |
Ara h 8 |
Allergen Component |
1.4 |
Ara h 9 |
Allergen Component |
<0.1 |
Cor a 1 |
Allergen Component |
12.8 |
Cor a 8 |
Allergen Component |
<0.1 |
Cor a 9 |
Allergen Component |
<0.1 |
Cor a 14 |
Allergen Component |
<0.1 |
Differential Diagnosis
Rudi’s sensitization to the peanut storage protein Ara h 2 shows that he has an increased risk for severe reactions if eating peanuts.2 Strict avoidance of peanut is therefore recommended. With components, this risk could have been revealed before any reaction occurred.
Rudi’s birch allergy gives rise to cross-reactivity with the PR-10 protein Cor a 1 in hazelnut, and the itching in Rudi’s mouth when eating hazelnuts may originate from the pollen-food allergy.1
Rudi’s sensitization to birch pollen is confirmed, continue with current medication.
REFINED DIAGNOSIS
- Primary peanut allergy and birch allergy.
HEALTHCARE PROVIDER MANAGEMENT PLAN
- Rudi’s healthcare provider was advised that an open challenge with hazelnut might reduce the fear of severe reactions to hazelnut based on the family history.
- Rudi was advised to strictly avoid peanuts and always carry his emergency adrenaline autoinjector.
- Rudi’s healthcare provider arranged follow-up education and training on autoinjector use for Rudi and his family.
- Rudi’s healthcare provider advised him to continue to use antihistamines for the birch-pollen symptoms, starting treatment two weeks before the season.
FOLLOW UP
- Rudi is seen by his healthcare provider one year later. His autoinjector technique is checked and is satisfactory.
The people, places, and events depicted in these case studies and photographs do not represent actual patients, nor are they affiliated in any way with Thermo Fisher Scientific.
- Blankestijn MA, Knulst AC, Knol EF, et al. Sensitization to PR-10 proteins is indicative of distinctive sensitization patterns in adults with a suspected food allergy. Clinical and Translational Allergy. 2017;7:42. doi:10.1186/s13601-017-0177-4.
- Matricardi PM, et al. Molecular Allergology User's Guide. Pediatr Allergy Immunol. 2016: 27: (suppl23): 1–250.
