The heating’s on, my nose is running: is it a cold or an allergy in autumn?

The windows stay shut, the heating’s on – and your nose starts running straight away. Many people think this is the first cold of the year. But anyone who also suffers from hay fever should take a closer look right now. Because autumn is by no means a peaceful lull after the pollen season. It brings with it several sources of discomfort that can hide behind a seemingly harmless runny nose – and which can even overlap:

• Ragweed, also known as mugwort-leaved ragweed, flowers until the first frost, and in warm years well into November. Its pollen is extremely potent and can travel hundreds of kilometres.
• Mugwortis a classic late-summer and early-autumn allergen. It often strikes just as the grass pollen season is winding down. It is frequently confused with ragweed, as both have similar blooms and often occur together.
• Annual mugwort is a close relative that is becoming increasingly common in some regions and can further extend the period of symptoms.
• Late-flowering grasses can, depending on the weather, persist well into autumn and also extend the season.
• Although house dust mites are not pollen triggers, they are the most common cause of persistent autumn symptoms. Their peak season begins as soon as the heating is turned on.

It is important to note that it is often not a case of ‘either/or’. People who react to mugwort frequently also have problems with ragweed due to cross-reactions, and vice versa. If symptoms persist into the colder months, several triggers may be at play: the last traces of pollen outdoors, and dust mites indoors. Where the symptoms occur therefore provides the key clue as to which source is currently responsible for the runny nose.

Cold, hay fever or allergy? How to tell the difference

At first glance, the symptoms are very similar: a runny or blocked nose, the urge to sneeze, and constricted airways. However, there are clear signs that can help you distinguish an allergy from a cold or a simple runny nose.

The most important difference is the itching. With an allergy, the nose, eyes and roof of the mouth itch noticeably, whereas with a cold or a runny nose, this is virtually never the case. Nasal discharge also reveals a lot: with an allergy, it remains clear and watery for weeks and flows continuously, whereas with an infection it is also watery at first but quickly becomes yellowish and thick.

Fever, aching limbs, a sore throat and fatigue are not symptoms of an allergy. They are the hallmarks of a cold or an infection. An allergy, on the other hand, begins suddenly and persists for as long as the source of the symptoms is present. This can last from weeks to months. A cold develops over a period of hours to days and clears up within ten days at the latest.

“Anyone who still has the same runny nose after two weeks should reconsider,” advises Dr Markus Berger, allergy specialist, ENT doctor and board member of the Austrian Pollen Information Service. This is precisely when the cold season ends, leaving a suspicion of an allergy.

The location of the symptoms is also crucial. If your nose and eyes run mainly outdoors or when windows are open, this points to late-blooming pollens such as ragweed or mugwort. If, on the other hand, they occur mainly indoors, particularly in the bedroom and in the morning upon waking, house dust mites are the likely source of the symptoms.

The rule can be summarised as follows: itching and clear discharge without a fever almost always point to an allergy. A fever, a sore throat and thick, yellowish discharge suggest an infection. Ultimately, a test carried out by an allergist will provide clarity.

Why heated air exacerbates the problem

Many people with pollen allergies are surprised that their symptoms return in October. “In most cases, however, this isn’t a late extension of the pollen season, but a change in the source of the symptoms – and it no longer takes place in the park, but in the bedroom,” explains Berger. Depending on the region, between ten and 14 per cent of the population are sensitive to house dust mites.

These tiny arachnids are invisible to the naked eye. They thrive in damp conditions and therefore multiply rapidly in summer. When the air becomes dry due to heating, they die off in large numbers. The problem is that the allergens are found in their decomposing bodies and in their faeces, which have accumulated in mattresses and bedding over months. It sounds unpleasant, but it’s the same for everyone.

In the dry air from the heating, this turns into fine dust. It is stirred up simply by shaking out the duvet and lingers in the air for a long time. So fewer mites do not mean fewer symptoms – quite the opposite. What’s more, people spend much more time indoors during the colder months and ventilate less frequently. “For those with a mite allergy, autumn is therefore less of a mite problem than an indoor air quality problem,” says Berger.

This is precisely where the sources of symptoms overlap. The dust mite allergens in the home are present all year round, but it is only when the heating comes on that they really start to be stirred up. At the same time, pollen from outside is carried into the bedroom on your hair and outdoor clothing, so that in October the two often come together: the last traces of ragweed and mugwort pollen on the pillow and the dust mite allergens in the mattress.

How to protect yourself – in the bedroom and outdoors

If the bedroom is where the symptoms occur, Berger’s most important tip is to use so-called ‘encasings’ – that is, mite-proof covers for mattresses, pillows and duvets. If you have a confirmed dust mite allergy, statutory health insurance schemes will usually cover the costs on prescription. You should also wash your bed linen every one to two weeks at 60 degrees, as dust mites survive at 40 degrees. The bedroom should be cool, around 18 degrees, and you should airitthoroughly in the morning rather than leaving the windows tilted open all the time.

“Replacing a mattress without using encasing, on the other hand, is a waste of money, as the new mattress will be colonised again after just a few months,” warns Berger. The old tip about freezing bedding or soft toys is also a myth. Whilst the cold kills the mites, the allergens remain. “As far as the respiratory tract is concerned, it makes no difference whether the allergen comes from a live or a dead mite.”

But even outdoors, there’s no all-clear in autumn – particularly in eastern Austria. This region is considered a hotspot for ragweed, which flowers until the first frost and whose pollen can travel hundreds of kilometres. Together with mugwort, annual mugwort and late-flowering grasses, eastern Austria thus creates a prolonged period of symptoms that many allergy sufferers underestimate. During warm autumn weeks, Berger therefore advises: keep an eye on the pollen forecast, wash your hair in the evening and do not take outdoor clothes intothebedroom – otherwise, they will carry the pollen straight into your bed. Ultimately, the same simple rule applies to dust mites and pollen: the fewer allergens that make it into the bedroom, the more peaceful the night will be.

Not sure whether your symptoms are actually caused by an allergy?

If you’re not sure whether a runny nose is caused by an allergy, a cold or something else entirely, you can take matters into your own hands. The allergy risk questionnaire provides an initial assessment of how likely an allergy is. The pollendiary provides even greater accuracy: you record your symptoms over several weeks and check whether they coincide with current pollen counts. It is precisely this temporal correlation that is a strong indication that your nose is reacting to pollen – and not to an infection.

Whilst such tools are no substitute for a visit to the doctor, they provide valuable information that ensures you are well prepared for your appointment with an allergist. And, particularly in the case of persistent or unclear symptoms, this appointment is the next sensible step.

Key points at a glance

• A runny nose in autumn is often not a cold, but an allergy – to late-flowering pollen (ragweed, mugwort, annual mugwort, late-flowering grasses) or to house dust mites, and often even to both at the same time.
• Itching, clear nasal discharge and no fever suggest an allergy; a fever, a sore throat and nasal discharge that becomes thicker suggest an infection.
• If symptoms occur outdoors, think of pollen; if they occur indoors and in the morning, think of dust mites.
• In the bedroom, mattress covers, washing at 60 degrees, cool rooms and regular airing can help.
• Eastern Austria is a hotspot for ragweed – keep an eye on the pollen forecast.
• Unsure? Complete the allergy risk questionnaire and start keeping a pollen diary. 

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