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What is cough variant asthma?

Cough variant asthma (CVA) is a type of asthma that presents with a dry cough as the only symptom. The cough is also usually unaccompanied by mucus from the respiratory tract.

Cough variant asthma is a common cause of chronic coughs that can last more than two months.

How is cough variant asthma different from other types of asthma?

Unlike other types of asthma, CVA only presents with a dry, minimally productive cough as the primary symptom. If you have CVA, you are unlikely to exhibit other typical asthma symptoms such as wheezing, chest tightness, and shortness of breath.

Who can get cough variant asthma?

CVA can affect anyone, but it is more common in children¹. CVA may eventually evolve into classic asthma if not treated.

What causes cough variant asthma?

According to research², cough variant asthma shares several features with classic asthma, including the tendency to develop allergies. Therefore, potential triggers of traditional asthma attacks may also apply to your case. Triggers include:

  • Exposure to allergens such as pollen, dust, mold spores, and dust mites

  • Smoke and other air pollutants

  • Exercise

  • Cold air

What are the symptoms of cough variant asthma?

In addition to a dry cough that lacks phlegm or mucus, you are likely to report other symptoms, including suffering from airway inflammation and being more susceptible to allergies. You also may experience narrowing of airways when predisposed to allergic stimuli, medically known as airway hyper-responsiveness (AHR)³.

How is cough variant asthma diagnosed?

It can be challenging to diagnose cough variant asthma since it does not present with typical asthma symptoms such as wheezing, shortness of breath, and chest tightness. However, your doctor can find out if you have a suggestive medical history of the condition and conduct several tests to determine your lung function.

Pulmonary function tests

The doctor tests your lung function, which involves measuring your lungs' capacity to function correctly during inhalation and exhalation.

One such test is spirometry⁴. This involves breathing into a spirometer, which measures how much air you can breathe out in 1 second (forced expiratory volume in one second (FEV1))⁵ as well as the total amount of air you can breathe out of your lungs (forced volume capacity (FVC))⁶.

The test is repeated after taking a bronchodilator that opens the airways. Based on the difference in these to the baseline readings, the doctor will be able to determine whether you have asthma. However, this test form cannot be used in younger children whose lungs have not fully developed.

Bronchoprovocation challenge

Spirometry tests are not always conclusive because you can still obtain normal results even with cough variant asthma. The doctor may thus carry out the bronchoprovocation⁷ test to ascertain your condition. These tests entail exposure to substances that may trigger an allergic reaction. Common bronchoprovocation challenges include:

  • Exercise challenges⁸: A healthcare professional may ask you to conduct a physical task such as jogging or walking and measure your lung function before and after the exercise. You may start coughing after exercise if you have cough variant asthma.

  • Irritant challenge⁹: The healthcare professional will expose you to irritants or allergens that trigger asthma and monitor your airways for hypersensitivity.

  • Methacholine challenge¹⁰: During this challenge, you will inhale methacholine, a drug known to narrow your airways. Afterward, the doctor will observe your readings and compare them to the initial ones before taking the drug. If your lung function drops by at least 20%, the doctor may diagnose you with asthma. The methacholine challenge is usually more conclusive. It is done even when a spirometry test returns normal or ambiguous results.

Still, bronchoprovocation does not always yield informative results, as people with cough variant asthma are less hyper-responsive than those with classic asthma. Therefore, the tests may not always diagnose cough variant asthma.

Breath test

Elevated fractional exhaled nitric acid levels are symbolic of airway inflammation and can thus be used to diagnose classic asthma and CVA. Measuring the amount of this inflammatory gas released from your lungs can be used to conclusively determine the presence of cough variant asthma, where symptoms of classic asthma do not accompany the dry cough.

Differential diagnosis

Tests for other conditions may be carried out to rule out other causes of chronic coughs, such as:

  • Vocal cord dysfunction¹¹: Your vocal cords fail to open up fully, leading to blockage of the airways. The disease is often mistaken for asthma, including forms such as CVA.

  • Cystic fibrosis¹²: Inherited genes cause this disease. The disease may affect the digestive tract and the breathing system. The disease could also affect other organs. The disease has similar symptoms, such as lung infections, wheezing, and coughing, which may be accompanied by heavy mucus. The condition mainly affects the cells that produce sweat, mucus, and some digestive juices. Most people with cystic fibrosis are diagnosed as babies or children. 

  • Pulmonary embolism¹³: This refers to the blockage of arteries in the lungs. It may be caused by other illnesses, such as deep vein thrombosis (blood clotting in the legs). Your doctor should check for blood clots to ensure that they are not the cause of blockage in the breathing system. However, the disease differs from CVA because chest pain and shortness of breath may accompany it.

  • Congestive heart failure¹⁴: The condition is chronic — it develops over a long time and keeps reoccurring. In the case of congestive heart failure, the pumping of the heart muscle is affected gradually. Fluids may then accumulate in the lungs. You could experience shortness of breath. Your doctor may administer other tests to establish whether it is CVA or congestive heart failure. The illness differs from CVA in that it often involves swollen legs and a history of heart disease, such as a previous heart attack.

  • Chronic rhinosinusitis¹⁵: The condition involves blockage of the sinuses and nose. The shortness of breath that may result could be confused with CVA — mainly because it lasts for a long time. In the case of chronic rhinosinusitis, unlike in CVA, mucus drips from the nose to the back of the throat. You may also observe a reduced sense of smell and experience facial pain.

Treatment for cough variant asthma

The treatment for CVA is similar to that of asthma. You may get the following treatment options:

  1. Inhaled Bronchodilators¹⁶: The airways become blocked when the surrounding muscles tighten. Bronchodilators relax the muscles (around the airways) to keep air tracts open. Beta-2 agonists¹⁷ can be used as either short- or long-term bronchodilators.

  2. Short-term bronchodilators: These are used as needed and can ease muscles in an asthma attack or when you are about to engage in intense exercise. A good example is albuterol¹⁸. Notably, short-term bronchodilators are used to relieve asthma symptoms, not prevent them.

  3. Long-term bronchodilators: These are used to manage asthma and CVA. Your doctor may recommend daily use depending on your diagnosis. Typically, they are used with inhaled steroids.

  4. Inhaled corticosteroids (inhalers)¹⁹: CVA is commonly treated using inhaled corticosteroids. (inhalers). It is a common method for treating both CVA and asthma. Corticosteroid inhalers are effective in preventing the occurrence of wheezing. They also reduce inflammation and obstruction of the airways, easing symptoms such as chest tightness and shortness of breath. It would help if you used inhalers as prescribed, whether you have CVA or asthma. Your doctor may prescribe daily usage of an inhaler. Examples of inhalers include fluticasone (Flovent) and budesonide (Pulmicort). Follow your doctor's advice to understand the best inhaler for you.

  5. Nebulizers: A nebulizer is a simple machine — it turns liquid medication into a mist. Many asthma drugs come in a nebulized form and are useful for patients who cannot use inhalers. The medication can also be taken through a mouthpiece or a mask. Your doctor will explain how the nebulizer works and guide you on using it. Generally, you use a nebulizer by following these steps:

  • Make sure your hands are clean.

  • Based on your doctor's prescription, add the required amount of the medication to the cup.

  • Assemble the mouthpiece, tubing, top piece, and mask.

  • Follow the instructions and connect the tubing to the machine.

  • Once the nebulizer is set up correctly, you should turn it on. Note that the nebulizer may be powered electrically or by batteries.

  • To use the nebulizer, hold the medicine cup and the mouthpiece upright so the medication can be delivered.

  • Inhale all the medicine by taking slow but deep breaths.

6. Oral medications²⁰: Your doctor may supplement treatment options such as nebulizers and bronchodilators with oral medications²⁰. Sometimes oral corticosteroids are prescribed for severe asthma symptoms. Other oral medications your doctor may recommend you use are ones that stop the chemicals in your body that narrow your airways, such as zileuton (Zyflo)²¹ and montelukast (Singulair)²².

A team of health professionals will ensure the best management of your asthma or CVA to enable you to get the most effective interventions in matters such as medication and lifestyle advice.

How can you tell if you have cough variant asthma?

To know if you have CVA, you should consult your doctor. It can be a challenging condition to diagnose.  You may only experience a cough that is not accompanied by mucus. It is best to seek medical help when a cough becomes chronic.

Early diagnosis will enable you to reduce the risk of developing traditional asthma.

Luckily, your doctor can utilize several tests to establish whether you have CVA. Your doctor may carry out the tests discussed above and conduct an x-ray. The tests are necessary given that a chronic cough can be caused by several conditions, including chronic obstructive pulmonary disease (COPD)²³.

Steps that can be taken to reduce the risk of developing this condition

Like chronic asthma, you can avoid CVA by making some lifestyle changes:

  • Avoid exposure to smokeBoth smoking and inhaling second-hand smoke may irritate the airways, thus increasing the frequency and severity of asthma attacks. Therefore, you should avoid areas where people smoke publicly and ask friends and loved ones not to smoke in common areas such as the house and the car. Maternal smoking²⁴ also increases the risk of children developing asthma at some point. Therefore, avoid smoking when pregnant as it exposes you and the child to the risk of developing asthma (including forms such as CVA).

  • ObesityObesity has been linked with more asthma attacks than leaner patients. By effectively managing extra body weight, you may reduce the chances of developing CVA. Follow your doctor's advice, given that excess weight, could be caused by numerous factors such as medications, lifestyle, and decreased metabolism.

  • Exposure to allergens: Specific allergies such as allergic rhinitis (hay fever) and dermatitis (eczema) may increase your risk of developing CVA. Hay fever is commonly caused by exposure to allergens such as pet dander, insects, mold, and pollen. Eczema may be caused by stress, genetic factors, environmental triggers, and immune system over-activation.

  • Viral respiratory infections: Children who develop wheezing and other viral infections in the breathing tract when younger may develop CVA later. These infections include:

  1. COVID-19

  2. Common cold

  3. Bronchitis

  4. Sinusitis

  5. The flu (influenza)

  6. RSV (Respiratory Syncytial Virus)

You can manage the intensity and frequency of CVA asthma attacks through the following strategies:

  • Identify triggers: Understanding yourself is essential in CVA management, given that it could be triggered by numerous factors, such as smoke, sinusitis, and even exercise. It is best to consult your doctor to comprehensively identify triggers and develop an effective action plan to avoid them. Avoiding allergens will enable you to reduce attacks. You may need to make a few lifestyle changes based on the specific allergens that your doctor advises you to avoid.

  • Prevent colds: Colds caused by rhinovirus are a crucial risk factor to avoid when you have CVA. Avoid interacting with those with a common cold. Also, take measures such as washing your hands regularly to prevent getting a cold and avoid touching your face with unwashed hands.

  • Get vaccinated: Getting vaccines for diseases such as influenza will enable you to reduce the frequency and intensity of asthma attacks. Research²⁵ indicates that influenza may escalate the chances of an asthma attack or worsen symptoms.

  • Follow doctor's prescription when taking CVA medications: You should adhere to your doctor's advice to get good results in managing your CVA. You should take medications at the required time, for example.

  • Consider immunotherapy allergy shots: Research²⁶ indicates that allergy shots effectively prevent asthma attacks. Therefore, you should follow your doctor's advice when identifying the factors you are allergic to. This information is necessary to optimize the effectiveness of immunotherapy shots.

Are there any long-term effects associated with cough variant asthma?

CVA is different from bronchial asthma. The chronic cough that comes with it is a response to constriction of the bronchi. The cough response is minimal in bronchial asthma.

In the long term, CVA may lead to bronchial asthma. Therefore, with time you may observe symptoms such as increased shortness of breath, wheezing, and chest tightness. 

When to visit your doctor

Even a well-managed CVA could escalate into a dangerous incident. It would be best if you visit your doctor immediately when you observe the following signs:

  • You feel weak, dizzy, or out of breath.

  • You have trouble performing daily tasks such as cooking and cleaning.

  • You notice that your cough is not ending.

  • Your wheezing becomes worse even after taking your medication.

Respond faster when you witness the following signs as it may be an emergency:

  • Your nails or lips turn blue.

  • Your nostrils start flaring when you breathe in.

  • You start taking more than 30 breaths per minute.

  • Walking and talking becomes difficult.

  • The skin at the base of your throat stretches when you breathe in.

The lowdown

CVA is a common form of asthma, even though it is unusual. Therefore, you should seek medical help when a cough fails to clear. The only difference between CVA and asthma is that symptoms such as wheezing and chest tightness are absent in CVA.

Notably, CVA is most common in children. However, anyone can get it. CVA is also likely to develop into classic asthma. If it does, you may witness symptoms such as wheezing and tightening of the chest.

The resemblance between asthma and CVA is significant — it extends to factors such as triggers and manifestations. CVA may therefore be triggered by allergens such as smoke, dust, and exercise.

You may witness inflammation and narrowing of the airways when exposed to allergens. Diagnosing CVA may be challenging. However, your doctor can diagnose you with CVA by reviewing your history and performing special tests.

The treatment for CVA is similar to that of asthma in aspects such as oral medications, inhalers, and nebulizers. You should consult your doctor when you experience unusual signs, such as your fingers turning blue. You should also seek medical help when your medication fails to act as expected.

  1. Pharmacotherapy of cough-variant asthma (2007)

  2. Cough and asthma (2011)

  3. Airway hyperresponsiveness (2003)

  4. Spirometry (2022)

  5. Forced expiratory volume in one second and peak expiratory flow rate values in non-professional male tennis players (2006)

  6. Forced vital capacity and forced expiratory volume in six seconds as predictors of reduced total lung capacity (2008)

  7. Bronchoprovocation testing (1989)

  8. Exercise induced asthma (2022)

  9. Interactions of allergens and irritants in susceptible populations in producing lung dysfunction: implications for future research (2001)

  10. The metacholine test for the study of unspecific bronchial hyperreactivity in childhood (1986)

  11. Vocal cord dysfunction: a review (2015)

  12. Cystic fibrosis (2022)

  13. Acute pulmonary embolism (2022)

  14. Congestive heart failure (2022)

  15. Chronic sinusitis (2022)

  16. Bronchodilators (2022)

  17. Beta 2 agonists (2022)

  18. Albuterol (2022)

  19. Inhaled corticosteroids (2022)

  20. Asthma medications (2022)

  21. Zyflo | RxList

  22. Singulair | RxList

  23. Chronic obstructive pulmonary disease (2022)

  24. Maternal smoking in pregnancy and its influence on childhood asthma (2016)

  25. Flu & people with asthma | Centers for Disease Control and Prevention

  26. Impact of allergen immunotherapy in allergic asthma (2018)

Other sources:

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