The dark side of spring - nasty early bloomers

Sandra Wieser
03.04.2022 | 5 min de lectura

Spring has begun and for many people spring is the most beautiful time of the year. Most people are happy about the warmer temperatures and can hardly wait for the trees to turn green again - but not everyone. For allergy sufferers, the time of watery, itchy eyes and runny noses is around the corner.

The pollen load is particularly high in February, but in mild winters pollen can fly even in January. Warmth makes plants blossom, and it is estimated that every fourth to fifth adult (20-30%) is allergic to the pollen escaping in that process - and the trend is rising. Pollen allergy sufferers react allergically to so-called early bloomers such as hazel and alder.

Since allergies to these tree pollen are often accompanied by a birch pollen allergy, those affected suffer from allergic symptoms such as "hay fever" well into the summer. The reason for this is the close allergen relationship. In addition, cross-allergies with foods can occur due to the very similar allergen structures. Stone fruit and nuts in particular often cause problems in affected patients. The oral allergy syndrome often becomes apparent in these patients through tingling, itching, burning of the mouth, tongue, or lips.


Pollen allergy sufferers can feel it immediately: When the wind carries the pollen from the trees through the air, their nose becomes runny, and their eyes turn extremely itchy. An allergy to hazel or alder pollen usually manifests itself through typical "hay fever symptoms":

  • Sneezing, sniffling, coughing
  • Itchy, burning, watery eyes
  • Reddening of the skin

In general, the symptoms of a pollen allergy are mild, but symptoms can also become chronic and trigger allergic asthma.


It is advisable to consult a doctor if you suspect you have a pollen allergy. The doctor will carry out an allergy test, which consists of a skin test and/or a blood test.

The ALEX2® allergy test includes all relevant allergens that are necessary for a precise diagnosis.


An extract of hazel pollen is available as well as the major allergen Cor a 1. This is a member of the PR-10 family (Bet v 1 homologues) and is associated with inhalation symptoms. It can contribute to mild forms of food allergy (e.g., oral allergy syndrome) due to cross-reactions with various fruits and vegetables. PR-10 proteins are usually sensitive to heat and digestion, so cooked foods are usually well-tolerated.


The recombinant allergens Aln g 1 and Aln g 4 are included in the ALEX2® allergy test. Aln g 1 is a member of the PR-10 allergen family and is >90% identical to Bet v 1. Since the degree of cross-reactivity between Aln g 1 and pollen (hazel, birch) and food allergens from the PR-10 family is high, Aln g 1 sensitisation is associated with inhalation symptoms and mild forms of food allergy (e.g., oral allergy syndrome). Aln g 4 is a member of the polcalcin allergen family and is associated with inhalation symptoms. The degree of cross-reactivity between Aln g 4 and other members of the polcalcin allergen family is high.


There are several therapy options available to the treating physician. Symptomatic treatment in the form of antihistamine tablets, drops or sprays can be prescribed. Depending on the severity of the symptoms, hyposensitisation or allergen-specific immunotherapy may also be considered. A positive Cor a 1, Aln g 1 result serves as an indicator for immunotherapy if corresponding symptoms are present.