What is a mould allergy?

A mould allergy is really an allergy to the spores that mould produces. But, to understand why mould releases these spores, we need a quick biology lesson.

What is mould?

Mould is a type of microorganism known as fungi which can be found virtually everywhere. In other words, it can grow on almost anything in a moist, damp or musty environment, such as a pile of rotting leaves, grass cuttings or gone-off food.

Mould also grows in a slightly different way from plants or animals, by releasing ‘seeds’ (called spores) into the air. Being so small and lightweight, these spores can be readily spread in the water, by insects or in the air. They’re also very easy to inhale, meaning we often come into contact with them without noticing.

For people with a mould allergy, breathing in these mould spores can trigger an allergic reaction. This happens when the body mistakenly recognises spores as a potential threat, triggering the immune system to release certain antibodies and causing a variety of symptoms (but more on those later!).

When is mould allergy season?

There isn’t really a mould allergy season. Because mould is so common both indoors and outdoors, exposure is incredibly common but can vary from person to person.

However, in a similar way to the pollen calendar – which highlights when pollen counts are particularly high – mould levels do tend to rise based on the weather and certain times of the year.

For example, your likelihood of mould spore exposure typically increases during autumn and in wet weather.

That said, mould allergies can occur at any point throughout the year as well. So, it’s important to do what you can to limit your exposure.

Mould allergy symptoms

For people who are sensitive to mould spores, coming into contact with them can trigger several symptoms.

When inhaled, for example, mould spores may cause symptoms of a condition called allergic rhinitis (inflammation of the inside of the nose), often within minutes. This can then result in cold-like symptoms, such as:

• Sneezing
• An itchy, runny or blocked nose
• Itchy, red and watery eyes
• A cough
• An itchy roof of your mouth

If you have asthma and are allergic to mould spores, exposure may worsen asthma symptoms and trigger asthma attacks. So, talk to your doctor for advice on what you can do to reduce your potential exposure.

What causes a mould allergy?

Mould allergies are caused by exposure to mould spores, which are released into the air when moulds reproduce and grow.

While there are millions of mould species on earth, not all of them cause allergy symptoms. In fact, most types of mould spores live in harmony with humans and rarely cause disease.

Since moulds like damp environments, mould allergies can be brought on by exposure to areas with a lot of moisture. These can be found both inside and outside the house. Let’s take a closer look at where moulds love to hide:

• Inside the house: moulds can crop up on steamy windows, poorly ventilated kitchens and bathrooms, rubbish bins, window sills, damp basements and spoiled food in the fridge. They can also grow behind wallpaper, in the soil of houseplants and any particularly stuffy wardrobes, cupboards or under-sink cabinets.
• Outside the house: moulds love living in piles of leaves, grass clippings, compost heaps and garden sheds. They also thrive in high-moisture areas caused by external issues, such as leaky pipes or damage to your roof or window frames.

Mould allergy risk factors

Some people are more sensitive to mould than others and should try to avoid exposure as much as possible, such as:

• Babies and children
• Elderly people
• People with eczema
• People with asthma and other respiratory problems
• People with a weakened immune system
• People currently receiving chemotherapy

If you or anyone in your household (including your children) falls into any of these categories and you’re concerned about mould spore exposure, speak to your doctor. They’ll be able to discuss your specific circumstances and provide you with tailored advice. 

Mould allergy treatment

While dealing with a mould allergy can leave you feeling sneezy and uncomfortable, there are various treatments available to help alleviate your symptoms.

Decongestant nasal sprays can also help provide short-term relief from a blocked or stuffy nose by reducing the swelling of the blood vessels inside your nose. This can help open your airways, making it easier to breathe through your nose.

Antihistamines are a type of medicine often used to alleviate symptoms of allergies. They work by blocking the effects of a substance called histamine that gets released in your body when you come into contact with mould spores, helping to prevent symptoms like itchy eyes and a runny nose.

With this in mind, keep an eye out for Clarityn® Allergy Tablets when visiting your local pharmacy.

Clarityn® Allergy Tablets are a form of antihistamine that can offer 24-hour relief from allergy symptoms caused by over 150 indoor and outdoor allergens, including mould spores. Whereas Clarinaze® Allergy Control Nasal Spray is a steroid nasal spray designed to reduce and treat hayfever symptoms, such as sneezing or a runny nose.

If your symptoms don’t improve after taking these types of medicines, speak to your doctor for their advice, as you might require an alternative treatment.

How to manage a mould allergy

Mould allergy treatments can be an effective way to help manage and alleviate symptoms when they appear. But minimising your potential exposure to mould spores is also crucial.

To help manage your mould allergy moving forward, consider these helpful tips:

• Keep your home dry: since mould loves damp places, using a dehumidifier may help to keep the air dry inside your home. Repairing any leaks you find in your roof, walls or plumbing may also help to reduce your exposure.
• Clean regularly: try to clean your home often, paying close attention to areas that can get damp, like bathrooms, utility rooms and kitchens. This includes cleaning all walls behind kitchen units and cupboards, as well as window frames and showers.
• Avoid damp areas: since mould thrives in basements, compost piles, fallen leaves, cut grass and wooded areas, try to avoid these environments to limit your exposure.
• Have a clear-out: mould loves old newspapers, houseplant soil, wood and old foam pillows and mattresses. If you have any of these in your house, try to either keep them outside the house or throw them away.
• Tread carefully outside: if you know you’re sensitive to mould spores, avoid going into any damp or musty buildings or country areas (especially during harvesting). What’s more, consider leaving outdoor tasks like cutting the grass and raking leaves to somebody else.

By following these steps, you should be able to limit your mould spore exposure and manage your mould allergy more effectively. However, if you’re looking for tailored advice specific to your needs and situation, speak to your doctor.

Keen to learn more about the different causes of allergies similar to mould allergies? If so, take a look at the full range of allergy articles we have available on our ‘About Allergies’ page.