Table of ContentsView AllTable of ContentsSymptomsCauseDiagnosisTreatment
Table of ContentsView All
View All
Table of Contents
Symptoms
Cause
Diagnosis
Treatment
Cough-variant asthma can be difficult to diagnose because chronic dry coughing can be attributed tomany conditions. But a diagnosis is important because treatment of cough variant asthma is not the same as treatment for other types of chronic coughing.
Wet vs. Dry Coughs
Verywell / Ellen Lindner
Cough-Variant Asthma Symptoms
Cough-variant asthma is confusing because it doesn’t have many features of asthma. A chronic, non-productive cough is the distinguishing feature, but there are not usually other typicalsigns or symptoms of asthma.
There are many reasons you could develop a chronic cough, which is defined as a cough lasting more than eight weeks in adults and four weeks in children. The timing of the severe coughing episodes could be a clue that asthma is involved.
Cough-variant asthma should be suspected if:
There is growing evidence that asthma is part of a continuum of disorders called the atopic march.Atopy, a genetic tendency toward allergic diseases, is believed to develop from early childhood.
The atopic march classically starts withatopic dermatitis (eczema), which can progress to food allergies and finally to allergic rhinitis (hay fever) and asthma. It is possible that cough-variant asthma is a transitional step in the march.
With that said, not everyone who has cough-variant asthma will develop classic asthma. A 2010 review of studies from Italy suggests that only around 30% of people with cough-variant asthma will go on to do so.
Prospective studies have also suggested that one of four people with idiopathic chronic cough (cough of unknown origin) have cough-variant asthma.
What Is Asthma?
Cough-variant asthma can be misdiagnosed, and it is a difficult diagnosis to confirm.
Asthma is mainly diagnosed based on your symptoms, medical history, and a variety of tests that evaluate your lung function. These tests, calledpulmonary function tests (PFTs), measure the capacity of the lungs and the force of exhalations after exposure to different substances. Other tests may be considered, as needed.
Pulmonary Function Tests
For adults and children over age 5, the first PFT used is calledspirometry. It involves a device called a spirometer into which you breathe so that yourforced expiratory volume in one second (FEV1)andforced volume capacity (FVC)can be measured.
Your initial FEV1 and FVC values are then retested after you have inhaled a medication called abronchodilatorthat opens the airways. Based on changes in the FEV1 and FVC values, the healthcare provider may be able to definitively diagnose asthma.
There are downsides to spirometry. It cannot be used in younger children whose lungs are still developing and it has a high rate of false-positives results.This makes borderline results much harder to interpret.
How Asthma Is Diagnosed
If spirometry test results are uncertain with a bronchodilator, another test called abronchoprovocation challengemay be conducted. For this test, the FEV1 and FVC values are compared before and after exposure to substances or events that can trigger allergy symptoms.
These include:
The problem with bronchoprovocation is that people with cough-variant asthma have lesshyperresponsiveness(airway sensitivity) than people with classic asthma and tend to be less responsive to methacholine and other stimuli.
Breath Test
A breath test for exhaled nitric oxide (an inflammatory gas released from the lungs) is highly predictive of cough-variant asthma even if all other tests are inconclusive.
Even if tests are not strongly conclusive, some healthcare providers will presumptively treat cough-variant asthma with ashort-acting rescue inhalerlikealbuterolif the symptoms are strongly suggestive of the disease. If the symptoms resolve or improve under treatment, it can help support a diagnosis of this condition.
Differential Diagnoses
There are other possible causes of chronic cough in thedifferential diagnosisthat your provider may consider during your evaluation.
This may include:
Possible Causes of a Chronic Cough
The treatment of cough-variant asthma is virtually the same as for classic asthma. If the symptoms aremild and intermittent, an albuterol inhaler may be all that is needed. If the symptoms are persistent, aninhaled corticosteroidlike fluticasone may be used on a daily basis to reduce airwayinflammationhyperresponsiveness.
Some healthcare providers endorse a more aggressive approach to treatment under the presumption that it may prevent the onset of classic asthma. This is especially true if coughing fits are severe.
In cases like these, the healthcare provider may prescribe a rescue inhaler, a daily inhaled corticosteroid, and a daily oral drug known as a leukotriene modifier until the chronic cough resolves. If needed, an oral corticosteroid may be added for one to three weeks if the coughing episodes are severe.
Once the symptoms are fully resolved, daily inhaled corticosteroids may be continued to prevent them from returning. A healthcare provider can then monitor your condition and determine how long daily treatment is needed.
How Asthma Is Treated
A Word From Verywell
Any cough that lasts more than eight weeks in adults or four weeks in children should not be ignored. Speak with your healthcare provider and keep a diary detailing when coughing episodes occur (such as at nighttime or after exercising). The different causes of chronic coughing are treated differently—getting an accurate diagnosis is the first step in getting treatment to relieve your cough.
How to Prevent or Control Asthma Attacks
7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Fujimura M.Pathophysiology, diagnosis and treatment of cough variant asthma.Rinsho Byori.2014;62(5):464-70.Liu W, Chen H, Zhang D, Wu F, Zhou L.A retrospective study of clinical features of cough variant asthma in Chinese adults.Allergy Asthma Clin Immunol.2019;15:3. doi:10.1186/s13223-019-0318-5Hill DA, Spergel JM.The atopic march: Critical evidence and clinical relevance.Ann Allergy Asthma Immunol.2018 Feb 1;120(2):1321-7. doi:10.1016/j.anai.2017.10.037Magni C, Chellini E, Zanasi A.Cough variant asthma and atopic cough.Multidiscip Respir Med.2010;5(2):99-103. doi:10.1186/2049-6958-5-2-99Trivedi M, Denton E.Asthma in children and adults-What are the differences and what can they tell us about asthma?.Front Pediatr.2019;7:256. doi:10.3389/fped.2019.00256Corrao WM.Pearls and pitfalls in the diagnosis of cough variant asthma.Allergy Asthma Proc.2018;39(6):466-7. doi:10.2500/aap.2018.39.4168Meneghini AC, Paulino ACB, Pereira LP, Vianna EO.Accuracy of spirometry for detection of asthma: a cross-sectional study.Sao Paulo Med J. 2017;135(5):428-33. doi:10.1590/1516-3180.2017.0041250517
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Fujimura M.Pathophysiology, diagnosis and treatment of cough variant asthma.Rinsho Byori.2014;62(5):464-70.Liu W, Chen H, Zhang D, Wu F, Zhou L.A retrospective study of clinical features of cough variant asthma in Chinese adults.Allergy Asthma Clin Immunol.2019;15:3. doi:10.1186/s13223-019-0318-5Hill DA, Spergel JM.The atopic march: Critical evidence and clinical relevance.Ann Allergy Asthma Immunol.2018 Feb 1;120(2):1321-7. doi:10.1016/j.anai.2017.10.037Magni C, Chellini E, Zanasi A.Cough variant asthma and atopic cough.Multidiscip Respir Med.2010;5(2):99-103. doi:10.1186/2049-6958-5-2-99Trivedi M, Denton E.Asthma in children and adults-What are the differences and what can they tell us about asthma?.Front Pediatr.2019;7:256. doi:10.3389/fped.2019.00256Corrao WM.Pearls and pitfalls in the diagnosis of cough variant asthma.Allergy Asthma Proc.2018;39(6):466-7. doi:10.2500/aap.2018.39.4168Meneghini AC, Paulino ACB, Pereira LP, Vianna EO.Accuracy of spirometry for detection of asthma: a cross-sectional study.Sao Paulo Med J. 2017;135(5):428-33. doi:10.1590/1516-3180.2017.0041250517
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Fujimura M.Pathophysiology, diagnosis and treatment of cough variant asthma.Rinsho Byori.2014;62(5):464-70.Liu W, Chen H, Zhang D, Wu F, Zhou L.A retrospective study of clinical features of cough variant asthma in Chinese adults.Allergy Asthma Clin Immunol.2019;15:3. doi:10.1186/s13223-019-0318-5Hill DA, Spergel JM.The atopic march: Critical evidence and clinical relevance.Ann Allergy Asthma Immunol.2018 Feb 1;120(2):1321-7. doi:10.1016/j.anai.2017.10.037Magni C, Chellini E, Zanasi A.Cough variant asthma and atopic cough.Multidiscip Respir Med.2010;5(2):99-103. doi:10.1186/2049-6958-5-2-99Trivedi M, Denton E.Asthma in children and adults-What are the differences and what can they tell us about asthma?.Front Pediatr.2019;7:256. doi:10.3389/fped.2019.00256Corrao WM.Pearls and pitfalls in the diagnosis of cough variant asthma.Allergy Asthma Proc.2018;39(6):466-7. doi:10.2500/aap.2018.39.4168Meneghini AC, Paulino ACB, Pereira LP, Vianna EO.Accuracy of spirometry for detection of asthma: a cross-sectional study.Sao Paulo Med J. 2017;135(5):428-33. doi:10.1590/1516-3180.2017.0041250517
Fujimura M.Pathophysiology, diagnosis and treatment of cough variant asthma.Rinsho Byori.2014;62(5):464-70.
Liu W, Chen H, Zhang D, Wu F, Zhou L.A retrospective study of clinical features of cough variant asthma in Chinese adults.Allergy Asthma Clin Immunol.2019;15:3. doi:10.1186/s13223-019-0318-5
Hill DA, Spergel JM.The atopic march: Critical evidence and clinical relevance.Ann Allergy Asthma Immunol.2018 Feb 1;120(2):1321-7. doi:10.1016/j.anai.2017.10.037
Magni C, Chellini E, Zanasi A.Cough variant asthma and atopic cough.Multidiscip Respir Med.2010;5(2):99-103. doi:10.1186/2049-6958-5-2-99
Trivedi M, Denton E.Asthma in children and adults-What are the differences and what can they tell us about asthma?.Front Pediatr.2019;7:256. doi:10.3389/fped.2019.00256
Corrao WM.Pearls and pitfalls in the diagnosis of cough variant asthma.Allergy Asthma Proc.2018;39(6):466-7. doi:10.2500/aap.2018.39.4168
Meneghini AC, Paulino ACB, Pereira LP, Vianna EO.Accuracy of spirometry for detection of asthma: a cross-sectional study.Sao Paulo Med J. 2017;135(5):428-33. doi:10.1590/1516-3180.2017.0041250517
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