Allergens: Pollen, Dust Mites, Mould and More

Contents

1. What is an allergen?
2. Pollen and pollen types
3. Pollen calendar for Türkiye
4. Health effects and symptoms of pollen
5. When does pollen rise?
6. House dust mites
7. What is in house dust?
8. Mould spores
9. Cats, dogs and other animals
10. Cockroach and insect allergens
11. Air pollution and fine dust
12. How to protect yourself
13. When to see a doctor
14. Frequently asked questions

What is an allergen?

An allergen is a substance that is harmless to most people but that the immune system of some people mistakes for a threat and overreacts to. Once the immune system becomes sensitised, it produces allergy antibodies (IgE); on later contacts, substances such as histamine are released and symptoms like sneezing, a runny nose and itchy eyes appear.

Allergens can enter the body by breathing, eating or touch. This page covers airborne allergens, the ones carried in the air and breathed in. It helps to split them into two groups:

• Outdoor allergens: pollen and outdoor mould spores. They change with the season and the weather, and come in through open windows.
• Indoor allergens: house dust mites, pet allergens, cockroach debris and moulds growing in damp spots. They are present all year inside the home.

Airborne allergens most often cause allergic rhinitis (hay fever), allergic conjunctivitis (eye allergy) and asthma symptoms, and can also worsen skin symptoms in people with eczema.

Pollen and pollen types

Pollen is the tiny grains plants produce to reproduce, too small to see one by one. Most allergy-causing pollen is wind-borne: these plants release huge amounts of light pollen that can travel a long way. Showy flowers pollinated by bees and insects have heavy, sticky pollen that stays out of the air, so they cause fewer allergies.

Allergy-causing pollen falls into three main groups:

Tree pollen

In the air from late winter to late spring. The main ones in Türkiye are hazel, alder, cypress and juniper, plane, poplar, oak and olive; birch pollen matters mainly in the north. Olive pollen is a major allergen on the Aegean and Mediterranean coasts, and cypress and juniper pollen in coastal cities as well as in Central Anatolia. Most of the yellow dust that covers cars in spring is pine pollen; it is very visible but causes fewer allergies than other pollen. The cotton-like fluff from poplars is generally not an allergen either, although it can carry other pollen that is in the air at the same time.

Grass pollen

Grasses are the most common cause of pollen allergy in Türkiye and worldwide. They peak in late spring and early summer. Uncut meadows, park and roadside verges and cereal fields are the main sources.

Weed pollen

Prominent in summer and autumn. The most important are mugwort, goosefoot and pigweed, wall pellitory (Parietaria) and ragweed. Wall pellitory releases pollen over a long season on the Aegean and Mediterranean coasts. Ragweed is a strong allergen; some of the ragweed pollen in the air over the Black Sea region and Thrace is blown in from neighbouring countries, and the plant itself is spreading along the Black Sea.

Pollen calendar for Türkiye

The calendar below shows roughly which allergen is in the air in which months across Türkiye. Seasons can start a few weeks earlier or later depending on the region, altitude and the weather that year. On the Aegean and Mediterranean coasts the pollen season starts earlier and lasts longer; in Central and Eastern Anatolia it starts later.

Peak season Present Low or none

If you know which pollen affects you, use this calendar to take precautions before your symptoms start. More: when does pollen season start in Türkiye? and the pollen season guide.

Health effects and symptoms of pollen

In people with a pollen allergy, pollen causes what is known as hay fever (allergic rhinitis). Symptoms start with the pollen season and ease when it ends:

• Bouts of sneezing, a runny or blocked nose
• Itching in the nose, palate and throat
• Itchy, watery and red eyes
• Coughing, wheezing, chest tightness and shortness of breath (especially in people with asthma)
• Tiredness, headaches, poor sleep and trouble concentrating

Pollen allergy should not be taken lightly: untreated allergic rhinitis can disrupt sleep and lower performance at school and work, can raise the risk of sinusitis and is linked to the development of asthma. In people with asthma, the pollen season can make attacks more frequent.

Some people also have cross-reactions: someone allergic to birch pollen, for example, may feel itching in the mouth when eating apples, pears or hazelnuts. This is called oral allergy syndrome.

Related pages: for people with pollen allergy, asthma and sensitive airways.

When does pollen rise and fall?

• Warm, dry and windy days bring the highest pollen.
• Many plants release pollen in the morning, while in cities pollen often peaks in the air in the afternoon and early evening.
• Light rain washes pollen out of the air; the hours after rain are usually easier.
• Thunderstorms, however, can break pollen into small fragments and trigger asthma in some people.
• Air pollution in cities can make pollen more allergenic and makes the airways more sensitive.

When to open the window: can you open the window if you have a pollen allergy?

House dust mites

House dust mites are tiny creatures related to spiders, invisible to the naked eye. They feed on shed skin flakes and live mostly in mattresses, pillows, duvets, carpets, sofas and soft toys. What causes the allergy is not so much the mites themselves as their droppings and body fragments, which get into the air when dust is disturbed.

Mites love warm, humid conditions. They are present all year, but symptoms often get worse in autumn and early winter, when homes stay closed and humidity rises. People with a dust mite allergy often notice symptoms on waking, when making the bed or after vacuuming.

What helps?

• Fitting mite-proof covers to mattresses and pillows
• Washing sheets and bedding often in hot water
• Keeping indoor humidity low and airing the home regularly
• Cutting down on carpets, heavy curtains and soft furnishings
• Using a vacuum with a HEPA filter and dusting with a damp cloth

A window filter does not affect dust mites; they live inside the home. More: dust allergy and mites, house dust allergy and mites.

What is in house dust?

House dust is not one substance but a mixture: textile fibres, skin flakes, dust mites and their debris, pet allergens, mould spores, road and building-site dust from outside, pollen and fine particles from city air. A windowsill that quickly turns dark shows how much of it comes from outside. More: why is there so much dust at home?

Mould spores

Moulds release spores into the air to spread. Mould spores are found both outdoors and indoors:

• Outdoor moulds (such as Alternaria and Cladosporium) rise in late summer and autumn, especially on humid, windy days, at harvest time and when leaves fall. Alternaria is an allergen strongly linked to asthma.
• Indoor moulds (such as Aspergillus and Penicillium) grow in bathrooms, kitchens, damp wall corners, around windows and in poorly ventilated rooms.

Besides nose and eye symptoms, mould allergy can trigger asthma attacks. Controlling indoor humidity, drying wet surfaces, ventilating the bathroom and kitchen and cleaning visible mould are the most effective measures. More: mould spores, mould spores and windows in autumn.

Cats, dogs and other animals

Pet allergy is caused not by fur but by proteins in the animal’s saliva, skin flakes (dander) and urine. Fur carries these proteins and spreads them around the home.

• Cat allergens are very small and light; they stay in the air for a long time, stick to clothes and are carried even into places without cats.
• Dog allergens are usually less common; levels vary from dog to dog, and no breed is truly “hypoallergenic”.
• Rabbits, hamsters, birds and horses can also cause allergies.

Keeping pets out of the bedroom, vacuuming often and washing or brushing the animal regularly reduce allergen levels. More: for pet owners.

Cockroach and insect allergens

Cockroach droppings, saliva and body parts are a strong indoor allergen, linked to asthma especially in cities. Keeping food covered, fixing damp and leaks and regular pest control reduce it. Allergy to bee and wasp stings is a different type of allergy that may need emergency care.

Air pollution and fine dust

Fine dust (PM2.5 and PM10) and gases in city air are not allergens, but they irritate the airways, can make allergy symptoms worse and can make pollen more allergenic. Take care when opening windows on days with high air pollution. More: city air pollution, what are PM2.5 and PM10?

How to protect yourself from allergens

During pollen season

• Follow the pollen forecast for your area and spend less time outdoors on high-pollen days.
• Open windows during calm or post-rain hours, not in warm and windy hours.
• Change your clothes and wash your hair and face when you come in.
• Do not dry laundry outdoors when pollen is high.
• Keep car windows closed and change the cabin pollen filter on time.
• Sunglasses and a hat reduce the pollen that reaches your eyes and hair.

Inside the home

• Control indoor humidity and deal with damp corners and mould.
• Use mite-proof bedding covers and wash sheets often in hot water.
• Use a vacuum with a HEPA filter and dust with a damp cloth.
• Keep pets out of the bedroom.

While airing your home: a window filter

For people with allergies, the hardest question is how to air the home without letting pollen and dust in. A window filter lets air through while the window is open and reduces how much outdoor pollen, dust and mould spores get inside, helping lower the allergen load without giving up fresh air. It has no effect on allergens produced indoors, such as dust mites and pets, and it is not a medical treatment. More: window pollen filter, things you can do at home for spring allergies.

When to see a doctor

• Symptoms last for weeks or affect your sleep or work
• Over-the-counter medicines are not enough
• The same complaints come back in the same season every year
• You have coughing, wheezing, chest tightness or shortness of breath

An allergist can identify your sensitivities with a skin test or a blood test and discuss treatment and, if needed, allergy immunotherapy. Call emergency services (112 in Türkiye) without delay for severe shortness of breath, swelling of the lips, tongue or throat, or fainting.

Frequently asked questions

Last updated: 24 October 2026