Pollen allergy in late summer and autumn?
Have you ever heard about pollen allergy in late summer and autumn?
Food allergies that are based on pollen allergy?
We are talking about weed allergy, ragweed and mugwort allergies, as well as pollen-related food allergies.
Pollen, mold and insect stings are common allergy culprits during the summer months.
But fresh fruits and vegetables, such as apples, grapes, melons, and celery can also cause allergic symptoms.
Is there a connection? The answer is YES.
This is known as pollen-food-syndrome.
Especially in summer, people eat a lot of fresh and raw fruits and vegetables and experience symptoms more frequently than in other seasons. Cross-reactive allergens found in both pollen and raw fruits, vegetables and some tree nuts can lead to mild food allergy symptoms, such as the oral allergy syndrome.
In Europe, allergic reactions to herbs are predominantly triggered by pollen from ragweed (Ambrosia artemisiifolia) and mugwort (Artemisia vulgaris).
Allergic symptoms range from allergic rhinoconjunctivitis to allergic asthma. Since some proteins from both allergen sources are cross-reactive, such as Art v 1 and Amb a 4, it is obvious that many patients are allergic to both mugwort and ragweed. Furthermore, many people who are allergic to mugwort have an oral allergy syndrome in line with pollen-food allergy syndrome due to lipid transfer protein sensitisation. (1) Due to overlapping flowering periods, similar habitats, polysensitisation and cross-reactive panallergens, genuine herb pollen sensitisation is difficult to diagnose with allergen extracts.
However, marker allergens for molecular allergy diagnostics are available: Amb a 1 (ragweed) and Art v 1 (mugwort). 90% of Ambrosia pollen allergic patients reveal IgE reactivity to Amb a 1 and 95% of Artemisia allergics to Art v 1, respectively. (2) Both allergens serve as marker allergens for specific immunotherapy if corresponding clinical symptoms are present.
Thus, molecular allergy diagnostics can be used consistently to identify the primary trigger and to support the selection of the herbal extract for specific immunotherapy.
mugwort major allergen Art v 1 (Plant Defensin)
mugwort allergen Art v 3 (panallergen nsLTP)
ragweed major allergen Amb a 1 (Pectate Lyase)
ragweed allergen Amb a 4 (Plant Defensin)
CCD free allergy diagnosis
Some weed pollen allergens are glycosylated, among them Amb a 1 and Art v 1. In this case, ALEX2® offers an automatic blocking of clinically irrelevant IgE antibodies against cross-reactive carbohydrate determinants (CCDs). This feature is important to reduce false positive test results and give reliable test results.
From pollen to food allergy….
Secondary food allergy, due to cross-reactive proteins in food and in pollen, is very common in pollen allergic patients. 72% of a study population with mugwort pollinosis have experienced food allergy. (3) Pollen-related food allergy mainly correlates with IgE reactivity to Art v 3 which is a nsLTP and known for its high cross-reactivity. Sensitisation to LTPs such as Pru p 3 from peach, Ara h 9 from peanut or Cor a 8 from hazelnut is prevalent (80%, 69% or 63%, respectively) among individuals with food allergy. Moreover, a mugwort-celery-syndrome based on cross-reactive LTPs from celery (Api g 2, Api g 6) was described. Usually, pollen-associated food allergies are characterised by mild clinical symptoms such as the oral allergy syndrome including itchy tingly mouth, throat, or lips. But sometimes it also can cause stomachache and very rarely a life-threatening reaction called anaphylaxis.
- doi: 10.1159/000089188
- doi: 10.1096/fj.02-0472fje
- doi: 10.4168/aair.2019.11.1.116