Birch allergy

Birch allergy (Betula) is one of the most common spring allergens in Croatia. Birch pollen triggers strong allergic reactions in sensitive people during March, April and May, when airborne concentrations can reach extreme levels. Symptoms of birch allergy include hay fever, watery eyes, sneezing and a blocked nose, and in allergy sufferers with OAS, reactions to fruit and tree nuts can also occur.

Typical symptoms of birch allergy are sneezing, a runny nose, watery and itchy eyes, a blocked nose, a scratchy throat and coughing. In about 70% of people allergic to birch, oral allergy syndrome (OAS) also develops - itching and a burning sensation in the mouth after eating raw apple, pear, cherry, peach, hazelnut, kiwi or celery. More severe cases may be accompanied by worsening asthma during the peak of the season (April-May).

The birch season in continental Croatia lasts from late March to the second half of May. Birch pollen concentrations usually peak in April, when values regularly exceed 100 grains/m³ of air. In coastal and Mediterranean Croatia the season starts 2-3 weeks earlier. Warm, dry springs prolong and intensify flowering, while rainy spells briefly reduce concentrations.

Birch is widespread throughout continental Croatia, especially in Slavonia, Zagreb and the Hrvatsko Zagorje region. In urban areas it is often planted as an ornamental tree (parks, tree-lined avenues). The highest concentrations are recorded in Slavonia and continental Croatia, while the coast and islands are far less affected.

During the peak of the birch season, avoid spending time outdoors in the morning and early afternoon hours (the highest concentrations). Keep the windows of your home and car closed and use an air conditioner with a HEPA filter. Shower after coming home and wash your hair before bed. Antihistamines and nasal sprays help control symptoms - consult an allergist about treatment before the season begins (by early March at the latest).

Birch pollen contains the Bet v 1 protein, which is cross-reactive with proteins in raw apple, pear, cherry, peach, apricot, hazelnut, kiwi, carrot and celery. Heat treatment (cooking, baking) breaks down these proteins, so cooked food usually does not trigger a reaction.

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