Some elements of Christmas are certainly more appealing than others, but there is one part few of us do without: the tree. With presents around the base and lights and decorations twinkling, it becomes the focal point of any home at this time of year.
Yet new research from the UK suggests that rather than enhancing the festive feel, the traditional Christmas pine tree may actually be making some people ill. Christmas Tree Syndrome - as it is known - is caused by a number of different moulds that grow on these trees. They are found on the trees naturally but they flourish and rapidly increase in number once inside our snug, centrally heated homes.
This came to light for the first time in a study conducted by allergy specialist Dr Lawrence Kurlandsky, who was interested to discover why respiratory illnesses peak around Christmas. He asked colleagues at the Upstate Medical University in New York to provide clippings of bark and pine needles from the Christmas tree they'd had in their home.
He and his team found 53 different kinds of mould present on 23 samples, according to the research published in the Annals of Allergy, Asthma and Immunology. These weren't everyday mould - 70 per cent were of the type that can trigger asthma attacks, sneezing and a runny nose. "I do think this study is very significant," says Dr Adrian Morris, an allergy specialist from the Surrey Allergy Clinic.
"It has been previously suspected that the Christmas tree might be causing allergies and allergy-triggered asthma in particular. Before this study it was thought that the tree pollen or even the weed killer applied to trees could be responsible. Now we know that it's the mould.
"What is so interesting about this study is that the mould they found in highest quantities on the trees - aspergillus, penicillium, cladosporium and alternaria - are the moulds most likely to trigger allergies."
These moulds can cause standard allergic rhinitis, leading to a streaming nose and sinus pain, but may also trigger an asthma attack.
"Around 10 per cent of the people with allergy-based asthma have attacks triggered by mould, and cladosporium is one of the main culprits for this," says Dr Morris.
"The number of cladosporium spores circulating often increase at this time of year anyway (it's typically found among rotting leaves or compost heaps) and this can cause outbreaks of asthma attacks that lead to A&E departments being inundated with cases."
The typical signs that your tree may be making you ill are if you suddenly have an asthma attack after the tree is brought indoors or if your nose suddenly starts running and you are sneezing, even though you don't feel as if you have a cold.
By the time the tree has been up for two weeks, the number of spores found in an average flat increase from 800 per cubic metres to 5,000??per cubic metre, according to other research quoted in the study.
"That is more than enough to trigger an allergic reaction," says Dr Morris. "To put that into perspective, with hay fever you need around 50 pollen per cubic metres to trigger symptoms in a hay fever sufferer."
For some people the effects of the mould can be severe. In around one in 500 people - such as those with a compromised immune system - the aspergillus mould will settle and grow inside their airways.
"This may cause the sudden onset of a cough and fatigue that won't shift," says Dr Morris.
"It is normally diagnosed with a blood test but can be hard to treat, as anti-fungal treatments don't work in the airways, so steroids usually have to be used instead."
And if that isn't enough to make you start to edge the Christmas tree towards the door, there is more bad news. It's not just the mould on the tree that can cause problems.
"Someone with a lot of allergies can be allergic to smells and just the smell of the Christmas tree - which comes from the pine resin - can trigger sneezes and wheezes in some people," says Dr Bill Frankland of the London Allergy Clinic.
"Also, if someone already has a respiratory allergy (such as to a pet or dust mites) then the lining of their nose is already over-secreting and sensitive and the mould on the Christmas tree may make the symptoms of their normal allergy worse."
However, as Christmas involves a lot of to-ing and fro-ing between friends and relatives it can be hard to identify whether your runny nose is due to the Christmas tree, dust mites at your friend's house or Auntie Ethel's cat.
"If your symptoms get worse in the room where the tree is and especially when you get close to the tree - for example, as you take presents off it - then it is safe to say the allergen causing your problems is coming from the tree," says Dr Frankland.
So if the finger of blame points to the tree what should you do about it?
Packing away the fairy and binning the tree is quite an extreme measure - especially as they are far from cheap.
'What you can do is to spray it with a mild bleach solution, as this will help kill off the mould,' advises Dr Morris. 'Do this before you take the tree into the house - and preferably when it is still wrapped up, as it will be easier. If you are suffering from mild sneezes or just a bit of a runny nose, then take antihistamines.
"The nasal sprays are the best because they work directly on the nasal passages where the allergic reaction to the mould is triggered."
The other option is to make do with an artificial tree instead. This is especially worth doing for parents who suffer from bad asthma or allergies.
"Their children may be what we call atopic - prone to developing allergies - and they may become sensitised to mould if exposed to it early on," says Dr Morris.
"If they get exposed to these moulds within the first year of their life, they may develop an allergy to them later on. Artificial trees are a safe option for allergy sufferers because they are made of plastic.
"Artificial trees won't develop mould and house dust mites (another common allergy trigger) won't gather on them when they get thrown in the loft after Christmas."
Fake trees may not deliver that lovely pine smell or create quite the same atmosphere as a real one. But if you've found yourself sneezing and wheezing recently, they're a solution not to be sniffed at.
- DAILY MAIL