Hay fever at a glance: causes, symptoms, relief

Hay fever affects approximately 21–23% of the population in Europe and results from an allergic reaction to pollen from trees, grasses, and weeds (Lake et al., 2017). For many, it evokes images of spring and summer accompanied by sneezing passersby and stuffy noses. But what exactly is behind this commonly used term? This page is designed to help you better understand hay fever—from its causes and symptoms to effective ways to relieve it.  

Table of Contents

• What is hay fever?
• Which allergens trigger hay fever?
• What symptoms occur with hay fever?
• How is hay fever diagnosed?
• How can hay fever be treated?
• Summary

What is hay fever?

Hay fever, medically known as allergic rhinitis, is a widespread condition affecting people whose immune systems are overly sensitive to certain substances in the environment, known as allergens. More precisely, hay fever is a form of allergic rhinitis and refers specifically to reactions that are seasonally triggered by pollen from trees, grasses, or weeds. These pollens are fine, lightweight particles produced by plants. When someone with hay fever inhales this pollen, the immune system mistakenly identifies it as a harmful invader. As a result, the immune system launches a defensive reaction to fend off the perceived threat. This reaction involves the release of histamine and other chemicals into the body, which are responsible for the typical symptoms of hay fever (MedlinePlus, 2022).

Is hay fever an inhalant allergy?

Yes, hay fever is a form of inhalant allergy that occurs when the immune system overreacts to particles in the air, especially pollen from trees, grasses, and weeds. Inhalant allergies are characterized by the fact that the allergens must be inhaled to trigger a reaction and that they primarily affect the respiratory system.

Other types of allergies, such as food allergies (e.g. nut allergy) and contact allergies (e.g. latex allergy), affect the gastrointestinal tract or the skin and are triggered by different mechanisms—through ingestion in the case of food allergies or through direct skin contact in the case of contact allergies (ACAAI, 2024).

Are there differences between hay fever and other forms of allergic rhinitis?

Yes, because although hay fever is often used as a synonym for allergic rhinitis, it is, as mentioned earlier, only one form of rhinitis. The following table provides a clear comparison between hay fever and other nasal conditions to help distinguish between them:

Source: Cleveland Clinic, 2023

Which allergens trigger hay fever?

The most common allergens include:

• Tree pollen (spring): In spring, pollen from trees such as birch, oak, ash, and poplar often triggers allergic reactions in many people.
• Grass pollen (late spring to summer): Grasses like ryegrass, meadow grass, and timothy grass bloom during the later spring months and summer. They are among the most common causes of hay fever worldwide.
• Weed pollen (summer to autumn): In late summer and autumn, weeds such as mugwort, ragweed, and ambrosia are major pollen sources that trigger allergic reactions.

Source: Cleveland Clinic, 2023

What symptoms occur with hay fever?

Hay fever occurs seasonally, typically in spring and summer when pollen levels in the air are highest. The specific months and severity of symptoms may vary depending on geographic location and weather conditions and include the following symptoms:

• Runny nose.
• Itchy eyes.
• Nasal congestion.
• Itching, skin rash.
• Coughing.
• Breathing difficulties.
• Fatigue.
• Irritability.

How is hay fever diagnosed?

The diagnosis of hay fever requires a careful assessment of the patient’s symptoms and medical history by a physician. To identify the exact allergens, allergy tests may be conducted:

• Skin prick test: In this test, small amounts of allergens are applied to the skin, which is then lightly pricked to introduce the substances underneath. An allergic reaction is indicated by redness or swelling at the test site.
• Specific IgE antibody test: A blood test that measures the amount of IgE antibodies directed against specific allergens. High levels indicate an allergic reaction.

Source: Mayo Clinic, 2022

Want to get an overview yourself?

An inhalant allergy test, like the one offered by Homed-IQ, can be helpful in cases of hay fever or suspected hay fever, as it identifies the exact triggers of the allergy. Knowing your individual triggers allows for the development of targeted avoidance strategies to effectively reduce symptoms. This test is easy to perform at home. If you want a broader overview of potential allergies, you may also consider the extensive allergy test, which screens for 295 different allergens associated with 167 specific allergies.

How can hay fever be treated?

Strategies for treating hay fever range from medical treatments and preventive measures to nutritional adjustments aimed at relieving symptoms.

Medical treatments

The selection of the appropriate treatment method should always be made in consultation with a doctor. Possible treatment options include:

• Antihistamines: These medications block the effects of histamine and can help relieve sneezing, itching, runny nose, and watery eyes.
• Nasal sprays: Steroid nasal sprays reduce inflammation and swelling in the nasal passages, improving nasal breathing.
• Eye drops: Anti-allergy eye drops can help reduce eye irritation and redness.
• Immunotherapy: For severe allergies, immunotherapy—also known as allergy shots—offers a long-term treatment option. It gradually desensitizes the immune system to the allergen. Through continuous and controlled exposure to increasing amounts of the allergen, the body can gradually build tolerance, reducing allergic symptoms over time.

Source: Mayo Clinic, 2022

Preventive measures

Preventive strategies aim to minimize contact with allergens and thereby reduce symptoms. Here are some proven approaches:

• Avoid allergens: Stay informed about pollen seasons and try to minimize exposure during these times by, for example, keeping windows closed.
• Air purifiers: Use air purifiers to reduce allergen levels indoors.
• Nasal irrigation: Regular rinsing with saline solution can help clear allergens from the nasal passages.
• Change clothes and shower: Change clothes and shower after returning home to remove pollen that may have stuck to your skin or clothing.
• Dry laundry indoors: Avoid drying clothes outside when pollen counts are high.
• Consider an inhalant allergy test: An inhalant allergy test from Homed-IQ can help identify specific allergens and enable more targeted avoidance strategies.

Source: Mayo Clinic, 2024

Role of nutrition

Although nutrition cannot cure hay fever, a balanced, anti-inflammatory diet can provide support and strengthen the immune system. The following foods may be beneficial:

In cases of hay fever, foods high in histamines or that promote inflammation should be avoided. These include aged cheeses, alcohol, processed snacks, dairy products, and foods high in sugar.

Summary

Hay fever is caused by an overreaction of the immune system to pollen from trees, grasses, and weeds. The condition occurs seasonally, mainly in spring and summer, and leads to symptoms such as sneezing, nasal congestion, and itchy eyes. Diagnosis can be made through specific tests such as the skin prick test or the specific IgE-antibody-test, which help identify the triggering allergens. Treatment options include medical measures such as antihistamines, nasal sprays, and immunotherapy, supported by preventive strategies like allergen avoidance and the use of air purifiers. Nutrition also plays a supportive role by including anti-inflammatory foods in the diet.