Alder Pollen Allergy

Alder pollen comes from alder trees, which are a type of tree that grows mostly in Europe and North America.

The pollen is tiny and floats in the air, especially during certain months. Pollen is how trees and plants reproduce by spreading tiny particles to help grow new trees.

The pollen from alder trees is often carried by the wind, and people can breathe it in without even knowing.

People who are allergic to alder pollen may also have similar reactions to other tree pollens, like birch and olive pollen. These trees release pollen in a similar way, and the symptoms can be very alike.

Other types of pollen allergies include grass pollen, mugwort, and ragweed, which can cause similar sneezing, runny noses, and itchy eyes.

Symptoms of an Alder Pollen Allergy

If someone has an alder pollen allergy, their body reacts when they breathe in the pollen. The immune system treats the pollen like something harmful, even though it is not dangerous. Here are some common symptoms of an alder pollen allergy:

• Sneezing a lot
• Runny or stuffy nose
• Itchy or watery eyes
• Coughing
• Feeling tired or having trouble sleeping
• Sometimes, people might get a headache

If someone already has asthma, alder pollen can make it worse by causing more coughing and difficulty breathing.

Where is Alder Pollen Found?

Alder trees are mostly found in Europe, North America, and parts of Asia. They like to grow near rivers and streams. Alder trees are very common in places like the UK, Belgium, Germany, and the Netherlands.

For example, cities like London, Munich, Brussels, and Amsterdam often have high alder pollen counts during the spring. According to the Vienna Pollen Service at MedUni Vienna, the black alder (Alnus glutinosa) is particularly widespread in Vienna, and experts advise alder allergy sufferers to avoid walking in floodplains and near the Danube River where pollen concentrations are many times higher near the source.

When is Alder Pollen Season?

Alder pollen season is more complex than many other pollen seasons because it involves several different alder species that flower at different times.

Purple alder (Alnus x spaethii): This hybrid tree, often planted in parks and along streets in cities, is the first to flower. It can start releasing pollen as early as the end of December, extending the alder pollen season. According to pollen experts, the season can actually begin in the last days of December with the flowering of the Spaeth's alder.

Grey alder (Alnus incana) and black alder (Alnus glutinosa): These native alder species flower later. The grey alder typically starts to flower at the end of January, followed by the black alder, depending on weather conditions. In most parts of Austria, the main exposure phase for alder ends between the end of March and the beginning of April. In Switzerland, the hazel and alder season typically comes to an end towards the end of March.

Green alder (Alnus viridis): This species, found in alpine areas, releases pollen later, between the end of May and the end of June.

Pollen counts are typically higher on warm, dry, and windy days. Checking local pollen forecasts can help you know when alder pollen levels are high and plan your activities accordingly.

Treating an Alder Pollen Allergy

There are several effective ways to manage an alder pollen allergy:

• Avoiding Pollen: Try to stay indoors on days with high pollen counts. Keep windows closed to prevent pollen from entering your home. If you have an alder pollen allergy, avoid walking in floodplains and near rivers where alder trees commonly grow. Recognizing flowering plants and avoiding their vicinity is a great advantage, as pollen concentrations are many times higher near the source.
• Medication: Over-the-counter antihistamines and corticosteroid nasal sprays can help with symptoms. Eye drops can also reduce itchiness and redness.
• Nasal Rinses: Rinsing your nose with saline solution can help clear out pollen and soothe nasal passages.
• Allergy Immunotherapy: If symptoms are severe, a doctor may recommend specific immunotherapy. Alder pollen is part of the birch-family (Fagales) pollen group. Immunotherapy with birch pollen extract can be sufficient for many patients with allergies to related tree species such as alder and hazel, as it can modulate a cross-reactive immune response. Sublingual immunotherapy tablets are available for moderate to severe birch tree pollen allergy, which also target alder and hazel due to cross-reactivity. The treatment involves taking a daily tablet that dissolves under the tongue for at least three years to build tolerance.

Cross-Reactivity and Oral Allergy Syndrome (OAS)

If you are allergic to alder pollen, you may also experience itching, tingling, or mild swelling in your mouth, lips, or throat after eating certain fresh fruits, vegetables, or nuts. This is known as Oral Allergy Syndrome (OAS) or Pollen Food Allergy Syndrome (PFAS).

It happens because your immune system mistakes proteins in some foods for alder pollen proteins. Allergy Partners notes that depending on where you live, anywhere from 20 to 70 percent of people who are allergic to birch and alder pollens will also have oral allergy syndrome.

Common trigger foods for people with alder pollen allergy include:

• Fruits: Apples, cherries, peaches, pears
• Vegetables: Celery
• Herbs: Parsley
• Nuts: Almonds, hazelnuts

Cooking or peeling these foods can often reduce or prevent the reaction. However, if you experience symptoms with nuts, it is best to consult an allergist.

Hazel, alder, and birch are closely related and can trigger cross-allergies. Those who are allergic to one of these early bloomers may also develop symptoms with nuts, carrots, or apples.

Check Pollen Levels for Alder Pollen

See the current alder pollen levels across Europe on our Pollen Map (select "alder" on the map options).

You can also sign up for pollen alerts to be notified of high alder pollen days in your city.