Cough variant asthma is a type of asthma that is marked by a dry, nonproductive cough. Unlike other types of asthma, a person suffering from cough variant asthma often has no traditional asthma symptoms like wheezing or shortness of breath.
A cough is the most common reason why people seek medical attention in the United States.
Even though cough variant asthma (CVA) doesn't share more symptoms with regular asthma, it affects the body in several similar ways:
- Increases the risk of developing other allergic diseases
- Increases sensitivity of the airways
- Narrows and swells the airways, which disrupts air flow
Classic asthma generally has more serious implications than CVA. However, 30 to 40 percent of adults with cough variant asthma go on to develop classic asthma. As a result, it is vital to recognize the signs and symptoms so that proper treatment can be sought.
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Causes of cough variant asthma
CVA may appear after exposure to allergens or sinusitis.
The causes of cough variant asthma are not entirely understood.
However, it often appears after:
- Exposure to allergens
- Breathing in cold air
- An upper respiratory infection like sinusitis
- Starting to take beta blockers, a type of drug that treats high blood pressure, heart disease, and migraines
- Taking aspirin
There is a clear link between asthma and allergies. As many as 80 percent of all asthma sufferers also have nasal allergies. As allergies are a result of the immune system overreacting to a substance that should not normally cause a reaction, there may be an immunology link to cough variant asthma as well.
Certain people may be at a high risk for developing cough variant asthma and other allergic diseases. Knowing the risk factors for cough variant asthma and if a patient has them may help a doctor to make a diagnosis.
Risk factors include:
- Having another allergic condition
- Having regular asthma
- Having a relative with asthma
- Being overweight
- Smoking or exposure to secondhand smoke
- Exposure to environmental or occupational irritants
Symptoms of cough variant asthma
Unlike classic asthma, cough variant asthma often has no other symptoms besides a chronic cough that doesn't produce mucus. A chronic cough is any cough that lasts more than 8 weeks in adults and more than 4 weeks in children.
Cough variant asthma is not serious on its own but may progress into classic asthma.
Cough variant asthma is not often serious on its own. However, suffering from a chronic cough can be disruptive.
A cough from cough variant asthma may cause:
- Sleep disruption
- Cracked or fractured ribs
If cough variant asthma is not treated and managed properly, it may also progress into classic asthma. Cough variant asthma itself is not serious, but classic asthma can be.
Classic asthma symptoms include the following symptoms in addition to a cough:
- Difficulty breathing
- Chest tightness
- Shortness of breath
- Asthma attacks, episodes where air cannot reach the lungs due to airway narrowing
Classic asthma can have some serious complications. It's critical for a patient with cough variant asthma to get treatment to stop these complications from happening.
Complications can include things that disrupt the quality of life like fatigue and absence from work. Serious and potentially life-threatening complications can include:
- Permanent narrowing of the bronchial tubes
- Collapsed lung
- Asthma attacks that don't respond to treatment
- Lung failure
Diagnosis of cough variant asthma
It is not easy to know when to seek medical help for cough variant asthma. In general, the only symptom is a chronic cough.
People should see a doctor for a chronic cough if it lasts for more than 8 weeks with no known cause. If any of the following symptoms develop, people should see a doctor sooner to rule out other conditions or prevent cough variant asthma from progressing:
- A fever of over 100°F
- Shortness of breath
Because the main symptom is a chronic cough, it may be difficult for a doctor to diagnose it.
Other conditions or factors that cause a chronic cough can include:
- Bronchitis and other upper respiratory infections
- Post nasal drip
- Acid reflux and GERD
- Blood pressure medications
- COPD and chronic bronchitis
To diagnose cough variant asthma, other conditions that can cause a persistent cough must be ruled out.
As patients with cough variant asthma often have normal chest X-rays and spirometry tests, doctors may carry out a methacholine challenge. When inhaled, methacholine triggers coughing and bronchial spasms in everyone. However, an increased sensitivity to methacholine can indicate asthma.
If a doctor strongly suspects cough variant asthma, they may skip the methacholine test and prescribe asthma treatments. If cough symptoms improve with use of the asthma medications, the provider will diagnose cough variant asthma.
Treatment and prevention
Inhalers are frequently used to treat asthma.
The treatment for cough variant asthma is the same as the treatment for classic asthma. The right treatments vary by patient and can include a combination of the following:
- Inhaled corticosteroids or inhaled anti-inflammatory drugs that ease and prevent swelling in the airways
- Rescue inhalers or inhalers that reduce inflammation quickly in the case of an asthma attack
- Combination inhalers that combine both preventive medicines and fast-responding medicines
- Preventive oral medications that work to keep the airways open
Preventing cough variant asthma symptoms from flaring is the best treatment. People who are prescribed medications to prevent asthma symptoms should follow their doctor's orders to prevent episodes and keep cough variant asthma from worsening.
Steps can also be taken to reduce the risk of developing asthma. To lower the risk of developing asthma, people should:
- Maintain a healthy weight
- Know their personal risk factors
- Manage any allergic conditions properly
- Quit smoking
- Avoid secondhand smoke and other environmental and occupational irritants
While 30 to 40 percent of patients with cough variant asthma go on to develop classic asthma, some have no complications. While asthma is a lifelong condition, most asthma patients can lead normal, active lives if the condition is controlled with medications.
The more severe and less well-managed the asthma is, the more likely a patient will suffer long-term consequences.