A persistent cough (chronic cough) is a common symptom with many possible causes. Annoying effects of coughing, such as loss of sleep, sore chest muscles and leaking urine, can affect your quality of life and interfere with your daily activities. What does it mean if you have a cough that just won't go away?
It's important to note that a persistent cough doesn’t necessarily mean you need to be worried about lung cancer. There are many possible causes of this symptom, only one of which is lung cancer. But since the less common causes are often missed for some time, it is important to make an appointment to see your doctor even if you believe there is a good explanation.
What Is the Definition of a Persistent Cough?A persistent cough is defined as a cough that persists for a period of 8 weeks or longer. The cough may be dry, or you may cough up mucous. This is in contrast to an "acute" cough that lasts less than 8 weeks, such as those that occur with the common cold.
Some Possible CausesThe 3 most common causes of a persistent cough include:
- Postnasal drip from hay fever (allergic rhinitis), sinus infections, nasal polyps, or other conditions.
- Acid reflux.
Other common causes include:
- Infection. One fairly common cause of a persistent cough is the lingering cough of whooping cough (pertussis).
- Some medications, especially a category of high blood pressure medications known as ACE inhibitors. 10 to 20% of people on these medications develop a persistent cough.
- Eosinophilic bronchitis.
Less common causes of include:
- Benign and malignant tumors, such as lung cancer. For 2% of people with a persistent cough, lung cancer is the underlying cause.
- Lung diseases such as emphysema, bronchiectasis, and sarcoidosis.
- Fungal infections such as coccidiomycosis, histoplasmosis and tuberculosis.
- Inhaling a foreign object
- Heart failure.
Learn more about the causes of a chronic cough:
When to See Your DoctorIt is important to make an appointment to see your doctor if you have a cough that persists, even if you believe there is a reason to explain your cough, such as continued smoking or allergies. You should call your doctor immediately if you experience chest pain, shortness of breath or lightheadedness, or are coughing up blood.
Questions Your Doctor May Ask
- How long have you been coughing?
- Has the cough been worsening?
- Is the cough steady or does it come and go?
- Is it worse after meals, or is it worse at night?
- Is the cough dry, or have you been coughing up phlegm (mucus)?
- Have you coughed up blood?
- What other symptoms have you been experiencing? For example, fever, shortness of breath, allergy symptoms, wheezing, or unexplained weight loss?
- What other medical problems do you have?
- Has anyone in your family had similar symptoms? Do you have a family history of bronchitis, asthma, emphysema, or lung cancer?
- Do you, or have you ever, smoked?
- Have you been exposed to secondhand smoke?
- What medications are you taking (including herbal supplements)?
EvaluationDepending on the severity of your cough, your doctor will first want to control your symptoms to make you feel more comfortable. She will then recommend tests to determine the cause. Possible exams/tests may include:
- A careful history and physical exam
- Blood tests to look for signs of infection
- A chest x-ray to look for infection of any evidence of a tumor
- A CT Scan of your chest or a CT Scan of your sinuses to look for signs of infection or a tumor
- Allergy testing
- Pulmonary function tests to screen for lung conditions such as asthma and emphysema
- Esophageal pH testing to test for the presence of acid reflux as a possible cause of a persistent cough
- Bronchoscopy to check for foreign bodies or evaluate your airways for a tumor
- Laryngoscopy to examine your throat and voice box
TreatmentTreatment will depend upon the underlying cause, as well as the degree to which your cough is interfering with your day to day activities.
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Pratter, M. Overview of Common Causes of Chronic Cough. ACCP Evidence-Based Clinical Practice Guidelines. Chest. 2006. 129(1 Suppl):59S-62S.
Udaya, B. and M. Prakash. Uncommon Causes of Cough. ACCP Evidence-Based Clinical Practice Guidelines. Chest. 129(1 Suppl):206S-219S
Young, E. and J. Smith. Quality of life in patients with chronic cough. Therapeutic Advances in Respiratory Disease. 2010. 4(1):49-55.