What is a persistent cough?
Coughing is your body’s defensive reflex that keeps your airways clear of irritating or obstructing substances (e.g., mucus) so you can breathe effectively. A cough can be dry or it can be productive, meaning that you are coughing up mucus (also known as phlegm or sputum). A cough is one of the most common reasons people visit their primary care doctor.
Primary care physicians often categorize coughs into acute (lasting less than three weeks), subacute (lasting three to eight weeks), and persistent (lasting eight weeks or longer).
A persistent cough is a symptom of a wide variety of mild to serious diseases, disorders and conditions including infection, inflammation, trauma, malignancy, airway obstruction, and other abnormal processes.
A persistent cough can be due to fairly mild conditions, such as postnasal drip following a cold. A persistent cough in someone who smokes is usually due to smoking and may lead to chronic bronchitis. A persistent cough can also be due to life-threatening diseases including congestive heart failure or tuberculosis. Allergic problems and certain medications can cause cough as well. Some individuals taking angiotensin-converting enzyme inhibitors (ACE inhibitors) experience a persistent dry cough, which ceases with drug discontinuation.
A persistent cough can be a sign of a serious or life-threatening disorder. If you have difficulty breathing, chest pain, rapid heartbeat, swollen legs or ankles, or are coughing up blood or pink, frothy mucus, seek immediate medical care (call 911). Coughing up blood or pink, frothy mucus is a sign of pulmonary edema, which can lead to respiratory arrest. Any sign of blood is a potentially serious problem.
What other symptoms might occur with a cough?
A persistent cough may occur in conjunction with other symptoms, which vary depending on the underlying disease, disorder or condition. Other symptoms include fever, difficulty breathing, and chest pain. Some symptoms, such as sounds the lungs make while you are breathing, changes in blood pressure, and low blood oxygen levels may only be evident using certain instruments in the doctor’s office or hospital.
Common symptoms that may occur along with a persistent cough
Persistent cough may occur with other symptoms including:
Coughing up clear, yellow, light brown, or green mucus
Flu-like symptoms (fatigue, fever, sore throat, headache, aches, and pains)
Red, inflamed throat
Other symptoms that may occur along with a persistent cough
Persistent cough may occur with less common symptoms including:
Fatigue
Unintentional weight loss
Serious symptoms that might indicate a life-threatening condition
In some cases, a persistent cough may occur with other symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, are exhibiting any of these life-threatening symptoms:
Coughing up blood or blood-tinged mucus or spit
Coughing up pink, frothy mucus
Difficulty breathing or shortness of breath
Difficulty speaking
High fever (higher than 101 degrees Fahrenheit)
Leg or ankle swelling
Painful cough or pain while breathing deeply
Severe pain upon swallowing
Unexplained weight loss or gain
What causes a persistent cough?
The most common causes of a persistent cough are asthma, postnasal drip, and gastroesophageal reflux disease (GERD). A persistent cough is not usually due to infection, although there are infectious diseases that are associated with a chronic cough. Less commonly, a persistent cough is due to life-threatening conditions, such as heart failure, pulmonary edema, or lung cancer. There are other possible causes as well, so talk to your medical professional about your symptoms.
Infectious causes of a persistent cough
A persistent cough can be due to certain infections including:
Respiratory tract infection
Tuberculosis
Other causes of a persistent cough
A persistent cough can be due to causes related to the respiratory, digestive and circulatory systems including:
Acid reflux or gastroesophageal reflux disease (GERD)
Airway irritation, such as from air pollution
Asthma and allergies
Chronic obstructive pulmonary disease (COPD, includes emphysema and chronic bronchitis)
Postnasal drip from sinusitis or upper respiratory infection, such as the common cold
Pulmonary edema
Smoking
Medications can cause a persistent cough
Certain medications that can cause a dry cough include ACE inhibitors to control high blood pressure (including captopril).
Questions for diagnosing the cause of a persistent cough
To aid in diagnosing the cause of your cough, your doctor or licensed health care practitioner will most likely ask you questions related to your symptoms including:
How long have you had the cough?
Are you coughing up anything?
Have you been sick recently (with the cold or flu)?
- Do you have any pets?
Do you smoke?
Is the cough keeping you up at night or interfering with your daily activities?
A persistent cough can be a sign of an infectious or inflammatory process, many of which can be easily treated. It is important to visit your health care provider when you experience a persistent cough without an obvious cause. Once the underlying cause is diagnosed, following the treatment plan outlined by your doctor can help lower your risk of potential complications associated with a long-lasting cough including:
Difficulty sleeping
Fainting spells from acute cough attack
Vomiting
Pulmonary hypertension
- Recurrent respiratory infections such as pneumonia
