Pollen Allergy (Hay Fever)
Examination and treatment of hay fever by ENT specialists – for children and adults.
Pollen allergy (hay fever, allergic rhinitis) is an allergic reaction to pollen from trees, grasses and weeds. It causes sneezing, itching, a runny or blocked nose, and red, itchy eyes during the pollen season. At Charlottenlund Privathospital, pollen allergy is diagnosed by ENT specialists using a skin prick test or blood test. The diagnostic assessment can be completed in a single visit. Both children and adults can be examined in Charlottenlund and at the hospital's clinics across Denmark. The specialist initiates and adjusts treatment with nasal sprays, antihistamine tablets and eye drops. For severe hay fever, allergen immunotherapy against birch and grass pollen may be offered, with treatment initiated in Charlottenlund.
What is pollen allergy?
With pollen allergy, the immune system reacts to pollen grains, which are harmless in themselves. The body produces antibodies (IgE) to pollen. When pollen lands on the mucous membranes in the nose and eyes, substances including histamine are released, causing symptoms. Hay fever is the common name. Doctors call it allergic rhinitis—or rhinoconjunctivitis when the eyes are also affected.
Allergic rhinitis is common. In a Danish population study, 23% of adults had allergic rhinitis, and more than four in ten of them had received no treatment in the previous year. More people have also become sensitised to airborne allergens over recent decades—but not everyone who is sensitised develops symptoms.
Source: Meteran H et al., Ugeskrift for Læger, 2026
What are the symptoms of hay fever?
Hay fever mainly affects the nose, eyes and throat, but many people also feel tired. When a blocked nose disrupts sleep at night, concentration at school and work can suffer. The Danish status article on allergic rhinoconjunctivitis describes how the condition reduces both quality of life and productivity. If symptoms return at the same time each year, pollen is likely to be the cause. If they are present all year round, dust mites, animals or mould are more often responsible.
Hay fever most often starts in childhood or adolescence, but it can also develop later in life. In a Swedish study of adults aged 20 to 59, 4.8% developed allergic rhinitis for the first time over an eight-year period.
Cross-reactions - itchy mouth after eating fruit and nuts
Many people with birch pollen allergy get an itchy mouth and throat after eating certain raw fruits, nuts or vegetables. Around 70% of people with a birch allergy experience symptoms after eating certain foods. This is because the substances resemble birch pollen, causing the immune system to mistake them for one another. Symptoms are usually limited to the mouth, and cooked fruit is often tolerated. The specialist will ask about cross-reactions during the assessment.
Is it hay fever or a cold?
Hay fever and a cold can both cause sneezing and a runny nose, so they can be difficult to tell apart. Itching is the clearest sign of allergy, and the eyes are more often affected than with a cold. Hay fever does not normally cause a fever, despite what the name suggests. If you have a fever, an infection is the more likely cause.
When is pollen season in Denmark?
According to the Danish Meteorological Institute (DMI), the pollen season in Denmark normally lasts from mid-February until the end of August.
The timing of symptoms depends on which type of pollen triggers your allergy, and pollen seasons can shift by several weeks from one year to the next.
The months below are based on Danish pollen measurements. If you react to several types of pollen, your symptoms may extend throughout spring and summer.
Weather conditions have a significant effect on pollen levels. Dry, sunny days usually bring higher pollen counts, while rainy or overcast weather tends to reduce them.
Pollen levels are generally highest in the afternoon and lowest at night. Mugwort pollen is an exception, with levels usually highest in the morning.
Daily pollen counts can be checked through DMI.
How Is Pollen Allergy Diagnosed?
The examination begins with a discussion about when and where your symptoms occur, what symptoms you experience, and which medications you have already tried.
The specialist will also examine the inside of your nose, as nasal congestion can have causes other than allergies.
During a skin prick test, a drop of each allergen is placed on the forearm, and the skin is gently pricked.
The test covers birch, grass, mugwort, dog, cat, horse, two types of house dust mites and two types of mould. The reactions are assessed after 15–20 minutes.
Antihistamine tablets must be stopped three days before the test because they can suppress the skin's reaction.
An IgE blood test can be used instead of, or alongside, the skin prick test. The blood sample is taken at the hospital, and the laboratory analysis is charged according to the laboratory's prices. Results are normally available within a few days.
Read more about allergy testing and the two methods here.
A positive test result does not necessarily mean that you have an allergy. It shows that your immune system is sensitised to a particular substance.
The specialist therefore always interprets the results alongside your symptoms. The findings are discussed during your visit, and a treatment plan is developed accordingly.
How is hay fever treated?
Treatment is tailored to where the symptoms occur and how severe they are. The specialist starts and adjusts treatment, including for people already using over-the-counter medication. According to the Danish Health Authority’s Rational Pharmacotherapy guidance, corticosteroid nasal spray is central to treatment and should be started before pollen season, as it can take up to two weeks to reach full effect. Pregnant women with hay fever can also be assessed and have their treatment adjusted.
What Can You Do to Reduce Symptoms During Pollen Season?
It is impossible to avoid pollen completely, but small changes to your daily routine can help reduce exposure.
These measures do not replace medication, but they can make the pollen season easier to manage.
- Keep windows closed in the afternoon when pollen levels are highest, and ventilate rooms late in the evening or at night.
- Dry laundry indoors during the pollen season for the types of pollen you are allergic to.
- Wash your hair and change your clothes before going to bed after spending time outdoors.
- Wear sunglasses to help protect your eyes from pollen.
- Rinse your nose with saline solution to help remove pollen.
- Monitor daily pollen counts and plan outdoor activities for days when pollen levels are lower.
When Is Allergen Immunotherapy an Option?
Allergen immunotherapy may be considered when symptoms remain severe despite correct use of medication and allergy testing confirms that pollen is the cause.
European guidelines recommend at least three years of treatment to achieve a lasting effect.
Allergen immunotherapy for birch and grass pollen can be given as a tablet placed under the tongue every day or as injections, initially every week and later every 4–8 weeks.
Treatment is started outside the pollen season, can be offered from the age of five, and lasts for at least three years.
It is available at Charlottenlund Privathospital, in the public hospital system or through specialists with public healthcare provider agreements.
Read more about the two forms of treatment, prices and available options on our Allergen Immunotherapy page.
How are children with pollen allergy assessed?
Children with pollen allergy are assessed by ENT specialists in the same way as adults, with a consultation, examination of the nose and a skin prick test or blood test. The assessment can take place in Charlottenlund and at the hospital’s clinics in several locations across Denmark. Pollen immunotherapy can be given from age 5.
Hay fever and asthma often go hand in hand. Hay fever increases the risk of developing asthma, and up to 80% of children with asthma are sensitised to allergens. If a child has symptoms after eating certain foods, the assessment is described under food allergy in children. Adults with signs of asthma should contact their GP.
Who will you see?
Pollen allergy is diagnosed and treated by ENT specialists in Charlottenlund and at the hospital’s clinics in several locations across Denmark. Skin allergies, such as allergies to metals or perfume, are assessed by the hospital’s dermatologist—see contact allergy. You can find the specialists on the staff page.
Frequently asked questions
Are pollen allergy and hay fever the same thing?
Yes. Hay fever is the common name for pollen allergy. Doctors call it allergic rhinitis, or rhinoconjunctivitis when the eyes are also affected.
Can hay fever cause a fever?
No. Hay fever does not normally cause a fever, despite what the name suggests. If you have a fever, it is more likely to be due to an infection, such as a cold.
Can you develop hay fever as an adult?
Yes. Hay fever most often starts in childhood or adolescence, but some people develop it for the first time as adults. In a Swedish study, 4.8% of adults aged 20 to 59 developed allergic rhinitis for the first time over an eight-year period.
When are pollen counts highest?
According to DMI, pollen levels in the air are usually highest in the afternoon and lowest at night. For mugwort, levels are highest in the morning. Dry, sunny days bring high pollen counts, while rainy and overcast weather brings low counts.
Should I stop taking allergy tablets before a skin prick test?
Yes. Allergy tablets suppress the skin reaction, so you should stop taking them 3 days before the test. If you cannot manage without them, a blood test can be used instead.
How long does pollen immunotherapy take?
Allergen immunotherapy is given for at least three years—as a tablet under the tongue every day or as injections, weekly at first and then every 4–8 weeks. Treatment starts outside pollen season, and its effect is assessed after one year.
Read Also
Pollen allergy is often associated with other conditions affecting the nose, airways and skin.