When winter is no longer a break
A stuffy nose, watery eyes, a scratchy throat – in the middle of January. Many blame it on an infection or the dry air from the heating. But for millions of Germans, the truth is quite different: Pollen season has long since begun. Hazel and alder, the first spring flowers of the year, have been releasing their allergens into the air for weeks. And while snow still lies outside, indoors the respiratory system is struggling with a double burden. It's a gradual process that many only notice when the symptoms become persistent. When a tissue becomes a constant companion. When at night the nose is so blocked that breathing through the mouth is necessary.
What used to begin in March now often starts as early as December. The pollen season is shifting earlier – and with it, a reality that is becoming increasingly burdensome for allergy sufferers. Respiratory disease experts now estimate the pollen season to last from January to October. Almost the entire year. Because in addition to the pollen from outside, there's a problem from inside: poor indoor air quality. Dry air from heating systems, stirred-up house dust, and a lack of humidity. Two worlds that reinforce each other. And respiratory systems that get no respite.
This article reveals what's happening right now – both indoors and outdoors. It explains why pollen in January is no longer an exception, but the new normal. It explores the role of cross-allergies, which many sufferers are unaware of, and why the air in our homes determines symptoms we often can't even explain. It delves into connections that are invisible – but become tangible once understood.
The silent harbingers of spring – when hazel and alder bloom in their winter coats
The German Weather Service has been reporting moderate pollen levels since mid-January 2026, especially in western Germany. The first hazel bushes were already in bloom on December 10, 2025. At the turn of the year, hazel pollen was flying across half of North Rhine-Westphalia. What sounds absurd has long since become the norm.
Experts from the German Weather Service confirm: Statistically, the pollen season has shifted forward by 16 days in the last 30 years. What used to begin at the end of February now often starts as early as the beginning of January. The reason is climate change. Milder winters bring plants into their development cycle earlier. Hazel, whose yellow catkins release their pollen even at just a few degrees above freezing, tops the list.
These pollen grains are tiny, light, and can travel hundreds of kilometers through the air. Anyone who wakes up with a stuffy nose and thinks it's the dry air from the heating may already be reacting to the first hazel pollen of the year. Furthermore, hazel, alder, and later birch belong to the same botanical family. Their allergens are so similar that an allergy to one of these trees almost always results in a reaction to the others as well. For allergy sufferers, this means the season lasts from January to May. Without a break.
The double burden – when pollen meets house dust
Around 70 percent of all tree pollen allergy sufferers also develop cross-allergies – to foods, but also to other indoor allergens. The immune system mistakes similar protein structures. An apple can suddenly become a problem. A hazelnut a threat. And house dust, which floats in the home all year round, a constant source of irritation.
Especially in winter, a disastrous combination occurs: Outside, the first pollen is in the air. Inside, the dry air from the heating system stirs up allergens. And the mucous membranes, already irritated by dry air, are left defenseless. In January, dry indoor air often has relative humidity levels of only 20 to 30 percent – far below the recommended 40 to 60 percent. The result: The mucous membranes dry out, their protective function fails, and allergens can penetrate deeper.
Furthermore, dry air allows dust particles to remain suspended in the air for longer. House dust mites themselves dislike dry air, but their droppings – the actual allergen – are not bound at low humidity; instead, they are stirred up. Allergy sufferers inhale an invisible cocktail of pollen, house dust, and other particles. A vicious cycle that repeats itself every morning.
When the apple suddenly becomes the enemy – cross-allergies that no one explains
A tingling sensation in the mouth after the first bite of an apple. Swollen lips after a handful of hazelnuts. An itchy throat from carrot juice. What many don't know: These are classic cross-allergies. The Bet v 1 protein from birch pollen is so structurally similar to the protein in many foods that the immune system can no longer distinguish between them. Doctors refer to this as birch pollen-nut-stone fruit syndrome – the most common cross-allergy of all.
Around 60 percent of food allergies in adults are such cross-allergies – particularly common in people allergic to early-blooming plants. The affected foods are:
- Nuts: Hazelnuts, walnuts, almonds
- Pome fruit: apples, pears, quinces
- Stone fruit: cherries, peaches, plums, apricots
- Vegetables: carrots, celery, parsley
- Soy: soy drink, tofu, soy flour
For many, it starts innocently enough: a tingling sensation, a slight itching. The symptoms are usually limited to the mouth area – the so-called oral allergy syndrome. But soy and hazelnuts, in particular, can trigger severe reactions – even shortness of breath and anaphylactic shock, especially when large quantities are consumed. Dietary products with a high soy content are especially risky for people with birch pollen allergies.
The insidious thing is that these allergies often develop gradually. For years, apples can be tolerated without any problems. Then, after a particularly high pollen season, the body suddenly reacts to related substances as well. Furthermore, the severity of the reaction depends on many factors. During pollen season, cross-reactions are often more pronounced. Physical exertion immediately after eating can also intensify symptoms. And not every apple variety triggers equally strong reactions – older varieties are often better tolerated than newer ones.
The invisible burden within your own four walls – Why indoor air becomes an amplifier
A hygrometer reveals the truth: In many bedrooms, humidity levels in January range from 22 to 28 percent. The recommended level is 40 to 60 percent. Some apartments even drop below 20 percent – comparable to a desert climate. What does this mean in concrete terms? Dry air irritates the mucous membranes. The cilia in the nose and bronchi, which normally remove pollutants, no longer function properly. Mucociliary clearance – the self-cleaning mechanism of the airways – comes to a standstill. The mucus layer becomes thinner. Allergens penetrate deeper. Inflammation develops more quickly.
Studies show that allergens remain suspended in the air for significantly longer periods when humidity is below 40 percent. They don't sink to the ground but stay at breathing level. Every step, every breeze redistributes them. For allergy sufferers, this means constant exposure without respite. The German Federal Environment Agency warns that dry air not only promotes the spread of allergens but also of viruses such as influenza and SARS-CoV-2. This is because virus-containing aerosol particles shrink due to water loss, become lighter, and remain suspended for longer.
In addition, there's pollen that's brought in from outside – on clothing, hair, and shoes. It settles in carpets, upholstery, and curtains. In well-ventilated rooms with sufficient humidity, it's bound. In dry rooms, it remains active. Someone who spends eight hours in the bedroom breathes eight hours of dry air full of allergens. The mucous membranes dry out. The immune system is working overtime. And when you air out the room in the morning, hazel pollen from outside is added to the mix.
Simple measures help: bowls of water on the radiator, damp towels, targeted ventilation instead of leaving windows tilted open, and more frequent changes of bed linen. A hygrometer often costs less than ten euros and objectively shows the humidity level. But irritated airways need more than just moisture. They need quality.
When air becomes medicine – Small steps, big impact
Salty air, like that found at the seaside, has been proven to have a soothing effect on irritated mucous membranes. It can alleviate inflammation, support the self-cleaning of the airways, and strengthen the immune system. That's why so many allergy and asthma sufferers go to the North Sea for spa treatments. The fine salt particles moisturize the mucous membranes, loosen stubborn mucus, and counteract inflammation. This principle has been known for centuries – graduation towers in health resorts have been using it since the 19th century.
But you don't have to move house to benefit from salty air. Some people report noticeable relief from salt air humidifiers or mini-graduation towers for their living spaces. These devices evaporate salt water, enriching the room air with fine salt particles. They are not intended as a replacement for medication, but rather as a complementary measure for humidifying the airways – a small, quiet, filter-free graduation tower for the home, with a high salt concentration and easy to use in everyday life. The advantage over pure water vapor: The osmotic effect of the salt enhances the humidifying and expectorant properties.
Allergies are complex. There's no single solution. But there are many small steps: optimizing humidity, purifying the air, ventilating properly, reducing allergens, and avoiding cross-allergies. And perhaps even a daily dose of salt air can help. Those who understand that January no longer means winter—at least not for allergy sufferers—can take action. Nature is changing. Pollen is appearing earlier. Cross-allergies are lurking. And indoor air quality plays a role that is far too often overlooked.
Ultimately, it's about creating spaces where the respiratory system can recover. Small steps that together make a big difference. Because we breathe around 20,000 times a day – and the quality of those 20,000 breaths determines how we feel. In January, in March, all year round.
(Images: Envato)
Medical note: This article is for informational purposes only and does not replace medical advice. If you experience persistent symptoms, shortness of breath, or allergic reactions, please consult an allergist or pulmonologist. Cross-allergies can, in rare cases, lead to severe reactions and should be medically evaluated.
