Do you have a ‘constant cold’ that won’t go away? Our expert reveals the surprising cause lurking in your home – and exactly how to get rid of it for good

Finding yourself more sniffly than usual as the weather turns colder? Experts say it might not be a common cold – but winter hay fever, triggered by hidden allergens lurking inside your home.

Runny noses, streaming eyes and itchy skin can all be symptoms of this little-known seasonal problem.

Hay fever, which affects millions of Britons every year, is usually worst in spring and summer when pollen levels rise.

But in the colder months, similar symptoms can strike for a different reason – allergens inside the home.

Also known as allergic rhinitis, winter hay fever is caused by exposure to dust mites, pet dander and mould.

As temperatures drop and we spend more time indoors, symptoms such as a runny nose, itchy eyes, congestion, sneezing and sinus pressure tend to worsen. 

In severe cases, it can even cause breathing problems and dizziness. And unlike a cold, it won’t clear up after a few days of rest.

But there are simple DIY fixes that will help ease symptoms, experts speaking to the Daily Mail have revealed. 

More than 16 million people in the UK suffer from hay fever – an allergic reaction to pollen spores that can last for weeks or months.

Those who escape the scourge of hay fever in spring aren’t necessarily immune in winter, says allergy specialist Dr Adrian Morris, from the Surrey Allergy Clinic.

‘Winter hay fever is a bit of a misnomer – hay fever is an allergy to pollen, so you can’t really have hay fever in the winter when there’s no pollen around,’ he explained.

‘What’s happening is allergic symptoms that mimic hay fever in the winter – but the allergen itself is different. And it would be relatively unlikely to be allergic to both.’

There are a few ways to tell whether your sniffly nose and scratchy throat are due to winter hay fever or just a cold, explains Niamh McMillan, pharmacy superintendent at Superdrug.

‘A cold will usually run its course within seven to ten days, whereas allergies can linger for weeks or even months,’ she said.

‘Mucus can also be a clue – allergy-related mucus is typically clear and watery, while mucus from a cold is thicker and yellow.

‘Sore throats are common with colds, but not with allergies. Facial itchiness or watery eyes are more likely to be allergy symptoms.’

Once you know what’s causing your winter hay fever, there are several ways to deal with it.

The most common culprit in the colder months, says Dr Morris, is house dust mites – invisible creatures that live in every home, feeding on dead skin cells and feathers in bedding and cushions.

While people aren’t allergic to the mites themselves, some react to their droppings, which can persist even when the mites have died.

This allergy tends to flare when the heating goes on, providing the warm, humid conditions mites thrive in.

‘People tend to close things up when it gets cold outside and spend more time indoors, which can cause allergies to flare up,’ said Dr Morris.

Luckily there are easy ways to reduce exposure.

‘If you are particularly allergic, swap feather duvets and pillows for synthetic ones – mites like to eat the feathers,’ he advised. ‘The older the bedding, the more likely it has mites.’

Bedding should be washed at least once a week – and on a hot wash – to kill off mites and droppings.

‘Thick carpets and plush furniture attract dust mites and should be hoovered regularly – but make sure to use a HEPA filter, otherwise you’ll simply redistribute them around the house,’ said Dr Morris.

He also recommends a good air purifier. ‘Dust mites like humid environments, so lowering humidity can help get rid of them,’ he said.

But mites aren’t the only trigger.

‘Another indoor allergen that can cause winter hay fever is mould spores that build up in damp areas like bathrooms and kitchens,’ says Ms McMillan.

‘To reduce these, keep your home well ventilated by opening windows when possible and avoid drying laundry indoors where moisture can lead to mould.’

Opening windows – even in winter – also helps with dust mites, adds Dr Morris.

‘Don’t leave damp washing lying around; if you can, tumble dry things,’ he said. ‘Drying clothes indoors with all the windows closed will create more humidity – causing more mould and more mites.’

Other mould sources can be brought in from outdoors in autumn and winter, such as leaf mould, says Dr Morris.

And if you find yourself sneezing more than usual at Christmas, you may even be reacting to mould that grows on the fronds of real Christmas trees.

The final source of winter hay fever, say experts, could be your pets.

‘You might start to get more of an allergic reaction to them when you’re inside with them more during the colder months,’ says Dr Morris.

If you’re allergic to your cat or dog’s fur, keep them out of the bedroom – and out of your bed. Wash them once a week (yes, even cats) and try products that reduce shedding.

If all else fails, try antihistamines or certain nasal sprays.

‘Just like for hay fever, antihistamines can help reduce allergic reactions,’ Dr Morris explained. ‘But low-dose steroid nasal sprays are actually more effective for winter hay fever – and can be bought over the counter from most pharmacies.’