Is it a Cold or Mould?

Written By emma davies

WHY YOUR AUTUMN SNIFFLES MIGHT BE A SIGN OF A MOULD PROBLEM

Falling leaves bring a surge of mould spores at this time of year, and the symptoms are easily mistaken for a cold.

Every autumn, my clinic fills with people convinced they’ve caught a cold that just won’t shift. A blocked nose, sneezing, itchy eyes, a general feeling of being under par. Sometimes it is a cold. But surprisingly often, the real culprit is lying on the ground outside: the falling leaves.

WHY AUTUMN IS MOULD SEASON

There’s a lot to love about autumn leaves, but as they fall and start to break down, they become a feast for moulds.

Common outdoor moulds such as Cladosporium and Alternaria thrive on damp, decaying leaf litter, releasing millions of tiny spores into the air. In the UK, mould spore counts rise through the summer and often stay high well into autumn, especially on warm, damp, windy days. Every time we rake the garden, kick through a pile of leaves or walk through damp woodland, we stir up a fresh cloud of spores, which are small enough to be breathed deep into the nose and airways.

At the same time, life moves indoors. The heating goes on, windows stay closed and laundry dries on radiators, creating the perfect conditions for condensation and indoor mould too. Moulds such as Aspergillus and Penicillium love the damp corners of our homes: around window frames, behind furniture, in bathrooms and on cold outside walls. So just as the outdoor spore season is winding down, many of us are spending more time breathing in the indoor kind, giving our immune systems little chance of a break.

WHAT’S HAPPENING IN AN ALLERGY

For most of us, breathing in mould spores is harmless. But in people with a mould allergy, the immune system mistakes them for a threat. It produces antibodies called IgE, which sit on immune cells known as mast cells. The next time the spores arrive, the mast cells release histamine and other chemicals, causing sneezing, a runny or blocked nose, itchy eyes and, in some people, a flare of asthma or eczema.

It’s a perfect example of the immune system over-responding to something that poses no real danger, and a reminder of why the goal is never to “boost” immunity, but to help it behave appropriately.

COLD OR MOULD? HOW TO TELL THE DIFFERENCE

A cold is more likely if you have:

  • A sore throat, aches or a raised temperature.

  • Thicker mucus that changes over a few days.

  • Symptoms that run their course within seven to ten days.

A mould allergy is more likely if you have:

  • Itchy eyes, nose or throat, and bouts of sneezing.

  • A clear, runny nose.

  • Symptoms that linger for weeks, or come and go.

  • Symptoms that get worse after gardening, a walk through damp woodland or time in a damp room.

No aches or temperature

THE HISTAMINE BUCKET

I often explain allergy-type symptoms to clients as a bucket of histamine.

Histamine isn’t the enemy. It’s a vital messenger, involved in immune defence, digestion, alertness and even our sleep-wake cycle. The problem comes when more histamine pours into the bucket than the body can clear.

WHAT FILLS THE BUCKET?

  • Allergens such as mould spores, pollen and house dust mites, which trigger mast cells to release histamine.

  • Histamine-rich foods, such as aged cheeses, cured meats, smoked fish, wine, beer, and fermented foods like sauerkraut and kombucha. Leftovers kept for several days build up histamine too.

  • Alcohol, which can both trigger histamine release and block the enzyme that breaks it down.

  • Stress and poor sleep, which can make mast cells more reactive.

  • Hormonal shifts. Oestrogen and histamine have a close relationship, as oestrogen can encourage mast cells to release histamine. That’s one reason many women notice histamine-type symptoms fluctuate with their cycle or change through perimenopause.

WHAT EMPTIES THE BUCKET?

The body clears histamine mainly through an enzyme called diamine oxidase, or DAO, which is made in the gut lining. A healthy, well-supported gut is better able to produce it, and DAO relies on nutrients such as vitamin B6, vitamin C and copper to work well. When the gut is inflamed or under strain, the bucket drains more slowly.

When the histamine bucket overflows:

For a while, the body copes. But once the bucket overflows, symptoms appear, and they can show up almost anywhere: a blocked or runny nose, sneezing, itchy skin, flushing, hives, headaches, digestive upset, a racing heart or disturbed sleep.

This is why autumn can tip people over the edge. Mould spores are added to dust mites as the heating goes on, there’s more indoor time and often more comfort food and drink, and the bucket that coped in summer starts to spill over. It’s also why two people can be exposed to the same spores and only one reacts.

The encouraging part is that you don’t have to remove every trigger. Lowering the overall load, while supporting the body’s ability to clear histamine, is often enough to bring the level back below the brim. In clinic, I often find that people troubled by histamine-type symptoms also have other signs of an overloaded immune system, and sometimes gut issues such as yeast overgrowth, which is one reason I like to look at the bigger picture rather than just the symptoms.

A note on fermented foods: they’re wonderful for the gut, and I recommend them in my seasonal gut article. But they’re also naturally high in histamine. If your bucket is already full, they may make symptoms worse for a while, so this is where an individual approach really matters. Strict low-histamine diets should only ever be short-term, ideally with support, so you don’t unnecessarily restrict the variety your gut needs.

SIMPLE STEPS TO REDUCE YOUR EXPOSURE:

Outdoors:

  • Wear a mask when raking or clearing leaves.

  • Don’t leave piles of wet leaves close to the house.

  • Shower and change your clothes after gardening.

  • Keep windows closed on damp, windy days, when spore counts are often highest.

Indoors:

emma davies
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Feed Your Gut this Autumn