With temperatures dropping to -4 to -5C in some parts of London, this weekend has been particularly bitter. In fact, some parts of the Highlands recorded -18.9C, which is the coldest temperature in the UK in the last 15 years! In London, the cold temperatures will have prompted many to stay indoors where dust mites and mould can thrive, further exacerbating winter allergy symptoms.
Despite the popular belief that allergies are a spring or summer issue, winter allergies can be equally disruptive. Sometimes, depending on the corresponding allergy, they can be even more problematic as we spend more time indoors.
Common Causes of Winter Allergy in London
House Dust Mites
Dust mites thrive in warm, humid indoor environments, such as central-heated homes. In winter, when windows are closed, and the heating is on, dust mites multiply, causing symptoms such as sneezing, a runny or stuffy nose, and itchy eyes.
We can’t see the dust mites with the naked eye, but if there’s dust, they will be there. They can also be present in the air after hovering or if there is a lot of activity in a room.
There are two common types of house dust mites, and we can easily test for both through a skin prick test. There is also good news in that if you are found to be allergic, then almost ‘curative’ treatment in the form of immunotherapy is an option. This is also called house dust mite desensitization and most people who take this notice a significant improvement in their symptoms. The medication is taken sublingually and is something that we can get you started on in our London allergy clinic.
Mould and Damp
Mould spores flourish in damp, poorly ventilated environments, which can be found in older or poorly insulated London homes—particularly during winter. When the temperature drops, people tend to seal off windows and doors to keep out the cold, inadvertently trapping moisture inside. The colder the temperatures, the less likely we are to open our windows as we don’t want the heat to escape. This creates an ideal breeding ground for mould, which can trigger respiratory issues, nasal congestion, and exacerbate conditions like asthma.
Although you usually cannot see mould spores floating in the air, the presence of patches or musty odours in bathrooms, kitchens, or near windows is often a tell-tale sign. If you suspect you are reacting to mould, an allergy test (including skin prick testing or specific IgE blood tests) can help identify whether mould is the culprit.
The good news is that once identified, mould allergies can be managed effectively. Strategies might include improving home ventilation, using dehumidifiers to reduce moisture, and regularly cleaning or treating areas prone to dampness. If your symptoms persist or worsen, we can explore additional testing or treatments in our clinic. Long term exposure to mould can cause other long term health problems so this is something important to address early. on.
Indoor Pet Dander
Although Primrose Hill is always popular with the loveliest dogs running around, pets do spend more time indoors when the mercury drops. This contributes to more dander in the air. Dander consists of microscopic flakes of skin and hair, which are easily inhaled or come into contact with your skin. Even short-haired pets can produce enough dander to trigger sneezing, itchy eyes, and other allergy symptoms.
Though you cannot always see pet dander, an increasing amount in confined spaces can aggravate symptoms, especially if you live with cats or dogs. The effect can be compounded if the house is also poorly ventilated. A skin prick test or blood test can confirm whether you are allergic to a specific type of pet dander. If results show a pet allergy, options for relief include reducing close contact with animals, investing in air purifiers, and vacuuming frequently using HEPA filters.
In some cases, allergen-specific immunotherapy for cat or dog allergens may offer long-term relief by gradually desensitising your immune system. If pet dander is affecting your quality of life, our clinic can work with you to create a tailored plan, helping you better manage symptoms whilst still enjoying the companionship of your furry friends. The pricing for immunotherapy will vary depending on the brand and type of allergy treated.
Air Pollution
London’s vibrant city life brings its share of traffic congestion and elevated pollution levels. As the atmospheric pressure drops, this can cause more of the air pollution to accumulate inside the city. Pollutants can become trapped at ground level, increasing exposure to particles that irritate the respiratory system and aggravate allergies.
While there is no single test for “pollution allergy,” individuals with sensitivities to particulates—such as exhaust fumes, dust, or smoke—may notice worsening symptoms during colder months. Since winter typically sees less airflow and ventilation, these pollutants can linger, triggering sneezing, congestion, or breathing difficulties.
Managing exposure to air pollution involves several strategies, such as using high-efficiency particulate air (HEPA) filters and avoiding outdoor rush-hour periods when possible. Indoor air purifiers may help reduce the amount of aeroallergens trapped in the air. With the right HEPA filter, the dust mites, pet dander and other pollutants will get trapped in the filter, thus reducing the particles floating around.
Although immunotherapy does not directly target pollution, it can help if you have specific allergic triggers like pollen or dust mites.
In our Holistic Allergy clinic, we can conduct comprehensive testing to differentiate between allergy trigger. We can also advise you on ways to lessen pollution-related discomfort, ensuring you breathe easier during winter’s chilly spell.
Overlapping Allergies and Multiple Triggers
Keep in mind that it is not uncommon for individuals to have more than one allergy trigger—such as dust mites, mould, and pet dander—all flaring up at once. When these triggers overlap, symptoms often become more intense or last longer, especially during winter when indoor environments can exacerbate the issue. The exact culprits can also be harder to identify.
The combination of prolonged heating, reduced ventilation, and increased time indoors effectively amplifies these overlapping allergies, making it harder for the body to cope. Identifying and addressing all relevant triggers through comprehensive testing is the best step to achieving meaningful and lasting relief.
Winter in London can be particularly challenging for those prone to allergies. The drop in temperature, increased indoor time and reduced variation can create the ideal environment for aeroallergens to thrive. However, with some understanding on what causes your allergy and what makes it worse, you can take the right proactive steps to mitigate the symptoms. If you found this post useful, you may also wish to check the rest of our educational blog posts written by our expert allergists.
