Asthma is a chronic disease of the airways of the lungs which inflames and narrows them. It is one of the major noncommunicable diseases. Some 235 million people currently suffer from asthma, Dr. Magdy Badran wrote.
Winter is an especially hard time for people with asthma. Hospital admissions for asthma increases during the winter months.
Cold-induced asthma is not the same as cold-allergy. Cold allergy takes the form of urticaria occurring on exposure, especially to cold water. Urticaria as a result of cold or cold water can lead to serious reactions such as swelling involving large areas of the body. Cold allergy can be a cause of allergic shock.
Cold Air is Dry
Several factors, including exercise and cold weather, can trigger asthma symptoms. Cold, dry air is a common asthma trigger and can cause bad flare-ups. That's especially true for people who play winter sports and have exercise-induced asthma. Wet weather encourages mold growth, and wind can blow mold and pollen through the air.
Inhaling cold can cause the airways to tighten, making it harder to breathe. The nose and mouth typically warm and humidify the air before it reaches the lungs, and this makes it easier to breathe. When the air is very dry and cold, as in the winter, it is more difficult for the body to warm.
When cold air hits the airways, the lungs react by tightening. Cold air contains less moisture, and breathing it in can dry out the airways. This can cause the airways to spasm, triggering an asthma attack, which can involve coughing.
When the temperature dips, going outside can make breathing more of a chore. Researchers once believed that the coldness of the air was the primary trigger of symptoms. However, the dryness, rather than the temperature, is the culprit.
Cold Air is Hard On Asthma Symptoms
The airways are lined with a thin layer of fluid. Breathing in dry air, that fluid evaporates faster than it can be replaced. Dry airways become irritated and swollen, which worsens asthma symptoms. Cold air also causes the airways to produce histamine. Histamine triggers wheezing and other asthma symptoms.
Cold-induced asthma can cause symptoms that include: chest pain, coughing, feeling short of breath, a sensation of tightness in the chest and wheezing. These symptoms tend to develop shortly after a person is exposed to cold air outdoors. They usually go away after the person reaches a warmer environment. However, an inpidual with more severe asthma may experience longer-lasting symptoms.
Cold Increases Mucus
The airways are lined with a layer of protective mucus, which helps remove unhealthy particles. Mucus keeps airways from drying out and helps to defend against invaders, including viruses and bacteria.
Though a healthy body requires some mucus, too much can be uncomfortable. Excess may be caused by infections, such as the common cold or flu, allergies, irritation of the nose, throat, or lungs, smoking tobacco products or chronic obstructive pulmonary disease. In cold weather, the body produces more mucus, but it’s thicker and stickier than normal. The extra mucus makes it easy to catch a cold or other infection.
The hypersecretion of mucus is an important cause of illness in patients with asthma. In asthmatics, the mucosa of the airways becomes swollen and oedematous, and mucus production increases in an attempt to rid the body of the allergen. Smooth muscle constricts, particularly around the terminal bronchioles, and breathing becomes difficult. Mucus transport slows and fluids accumulate in the air passages. Increased mucus production functionally leads to narrower airways, which makes it more likely for the patient to experience asthma symptoms. Additionally, the mucus production increases the risk of pneumonia as well as causes more cough as the body attempts to force the mucus out. Asthma can be fatal, and death is usually caused by blockage of the narrow airways with a plug of sputum.
Respiratory Infections Trigger Asthma
Common cold, flu, and other respiratory infections tend to circulate during the winter months. These common illnesses can cause inflammation (swelling) and narrowing of the airways. These changes could trigger asthma symptoms or an asthma attack.
You’re more likely to get sick or be indoors when it’s cold. Cold air can also drive the asthmatics indoors, where allergens like dust, mold, and pet dander flourish and may trigger asthma symptoms in susceptible inpiduals.
When you breathe through the nose, cold air is warmed and moisturized as it passes through the nose, throat, and upper airway, so by the time it reaches the lower airway, it is usually warm enough not to disrupt the moisture layer there. If breathing occurs through the mouth, the air is no longer warmed and humidified by the nose, so the drying effect on the lower airway may contribute to respiratory symptoms.
A combination of physical activity and breathing cold air can significantly worsen asthma symptoms. When you exercise, you breathe faster and deeper because your body needs more oxygen. You usually inhale through your mouth, causing the air to be dryer and cooler than when you breathe through your nose. The exercise that exposes you to cold, dry air is more likely to cause asthma symptoms than exercise involving warm and humid air
Tips to Avoid Asthma Attacks in The Cold
For anyone with asthma, working to control symptoms and reduce the number of attacks can help prevent symptoms from developing in cold weather.
Using a short-acting inhaler before going outdoors may prevent cold weather from triggering asthma. Try warming up for about 5–10 minutes before going outdoors and using a short-acting inhaler 10–15 minutes before going outdoors. Try breathing through the nose whenever possible.
Make sure your asthma is under control. See your doctor to develop an asthma action plan and then take the medicines your doctor prescribes. You may take medicine every day (for long-term control) or just when you need it (for quick relief).
Try to stay indoors when the temperature dips very low, especially if it’s below 12.2°C.If you do have to go outside, cover your nose and mouth with a scarf to warm the air before you breathe it in.
Wash your sheets and blankets every week in hot water to get rid of dust mites. Vacuum and dust your home often to remove indoor allergens. Drink extra fluids in the winter. This can keep the mucus in your lungs thinner and therefore easier for your body to remove. Avoid anyone who appears to be sick. Get flu vaccine.
Try to avoid other asthma triggers like tobacco smoke, strong scents, allergens such as pollen, mold, dust mites, animal dander, and stress.
Wash your hands frequently to reduce the risk of catching a cold or flu. Take care to avoid sharing towels, cups or other household items with someone who may have a cold. Get plenty of sleep and try to reduce your stress levels. Avoid touching your eyes, nose or mouth. Do not share your breathing equipment or medicines with others.
Appropriate management of asthma can enable people to enjoy a good quality of life. Don't ignore your symptoms, especially if you feel breathless or wheezy - you might think it's 'just a cold' but remember it could trigger a potentially life-threatening asthma attack.
Read also: articles by Dr. Badran