Learn About Cough
Cough is a human reflex, a spontaneous body response. When mucus, germs, and dust irritate your throat and airway your body automatically responds by coughing. Similar to other reflexes like sneezing or blinking, coughing helps protect your body.
• Cough is an important human reflex that helps protect your airway and lungs against irritants.
• Occasional cough is normal. It helps clear up your throat and airway from bugs, mucus, and dust. Persistent cough or associated with other symptoms like shortness of breath, mucus production, or bloody phlegm could indicate a more serious medical problem.
• Persistent cough is a common respiratory symptom but can also indicate disease of the heart, stomach and nervous system.
What Is Cough?
Cough is a human reflex. A reflex is an automatic response of your body to an irritant. Our throats and airways are equipped with nerves that sense irritants. Once stimulated, they send a signal to the brain. The brain, in response, sends a signal back to the muscles of your chest wall and abdomen to rapidly and forcefully take a deep breath in and breathe out really fast (in a fraction of a second) trying to remove the irritant. This response is almost instantaneous and very effective. Cough can propel air and particles out of you lungs and throat at speeds close to 50 miles per hour.
How Cough Affects Your Body
Occasional cough is a normal healthy response of your body. Our throats and lungs normally produce a small amount of mucus to keep the airway moist and to have a thin covering layer that works as an effective protective barrier against irritants and bugs we may breathe in. Some infrequent cough helps mobilize mucus and has no adverse effects on your body. Cough also allows for the rapid removal of toxins that we could accidentally breathe in.
As we grow older, muscles involved in cough tend to lose power and cough may not be as effective as it once was. This could lead to accumulation of mucus and inappropriate removal of toxins and bugs from your throat and airways. This could put you at higher risk of lung infections, something commonly seen in the elderly.
Although occasional cough is normal, persistent cough is not normal and it should always be brought to your physician’s attention. Cough associated with other symptoms such as runny nose, acid reflux, shortness of breath, chest pain, increased mucus production, colored or bloody mucus is most likely an indicator on an ongoing disease and needs medical attention.
How Serious Is Cough?
Cough is a common symptom seen in clinical practice. It affects 10% of the world population. Non-serious acute disease such as common cold can cause it. It is also important to know that very serious acute diseases, such as pneumonia, collapsed lung, lung clot, and fluid in your lung, could also cause cough.
People who have a history or smoking, chronic lung diseases such as COPD, asthma, seasonal allergies, acid reflux disease (Gastro esophageal Reflux Disease or GERD), lung cancer, and chronic infections such as tuberculosis, have chronic cough.
Cough can be of brief duration and self-limited. Cough can also persist until we identify and treat the cause of your cough. How serious cough is depends on the disease that causes it.
Cough Symptoms, Causes, and Risk Factors
Cough is seen in many medical conditions. It is important to take notes on the duration, type and features of your cough, as well as any other symptoms that come with your cough. This information will be very helpful to your physician when looking for the cause of your cough and the most appropriate treatment.
Cough is a symptom. We can classify cough by its duration and specific features:
- Acute cough: Sudden onset and last up to 3 weeks.
- Sub-acute cough: Lasts 3 to 8 weeks.
- Chronic cough: Persists for more than 8 weeks.
- Productive cough: Cough than brings up phlegm.
- Dry cough: Cough that does not bring up phlegm.
- Nocturnal cough: Cough that only happens at night.
- Hemoptysis: Coughing blood.
Cough can be the only symptom of an illness or it can present with other symptoms in diseases of the lung, heart, stomach, and nervous system. Some of the common symptoms associated with cough are:
- Shortness of breath
- Decrease in exercise tolerance
- Wheezing or a whistling breathing
- Runny nose
- Sore throat
- Weight loss
- Fever and chills
- Night sweats
- Difficulty swallowing / cough when swallowing
These are common causes of acute, or short-term, cough:
- Upper Respiratory Track Infections (or URTIs): This is the most common cause of acute cough. URTIs are infections of the throat almost always caused by viruses. They usually are associated with fevers, sore throat, and runny nose. In this group we include the common cold, viral laryngitis (makes your voice hoarse), and influenza. Bacteria such as whooping cough can also cause respiratory infections. This is a highly contagious respiratory infection. It produces a high-pitched “whoop” sound when taking a breath in. Cough could be so persistent that it can provoke vomiting.
- Hay fever (or allergic rhinitis): This common allergic condition could mimic the symptoms of a common cold. It is usually associated with dry cough, sneezing, and runny nose. There is usually an allergy trigger in the environment.
- Inhalation of irritants: Acute exposure to some fumes and vapors can cause inflammation of the throat and airway and cause cough.
- Asthma Attack: Asthmatic patients could develop acute dry cough (sometimes nocturnal) that is associated with shortness of breath and wheezing. This could be triggered by the inhalation of an irritant or by exercise, cold, stress or an acute respiratory infection.
- Acute Exacerbation of COPD (Chronic Obstructive Pulmonary Disease): Usually seen in smokers diagnosed with COPD. It presents with worsening baseline cough associated with change in the amount or color of phlegm.
- Lower Respiratory Track Infections (or LRTIs): An infection of the airways below the throat. Usually presents with dry or productive cough and fevers. It can affect the airways (bronchitis) or go further into the lungs (pneumonia).
- Lung Clot (or Pulmonary Embolism): A potential life-threatening disease where clots travel, usually from leg veins, to the lungs causing sudden shortness of breath.
- Lung Collapse (or Pneumothorax): This is caused by the deflation of the lung within the chest. It can be spontaneous or due to chest trauma. More commonly seen in smokers with history of emphysema (air pockets within the lungs). It presents with sudden chest pain, dry cough, and shortness of breath.
- Heart failure (or Pulmonary Edema): A weak heart can cause buildup of fluid in the lung. It presents with dry or productive cough, associated with worsening shortness of breath specially when laying flat and leg swelling.
- Post-nasal drip (or Upper Airway Cough Syndrome): It presents as dry cough caused by the chronic dripping of mucus from the back of the nose to the throat. Usually after a recent infection or continuous exposure to an allergy trigger.
- Gastro-esophageal Reflux (or GERD): It is also commonly known as acid reflux disease. The acid within the stomach backs its way up to the esophagus. It can potentially leak into the throat causing irritation and dry cough. It is usually associated with heartburn.
Some of the causes of acute cough can continue beyond 3 weeks and cause sub-acute and chronic cough.
Some causes of chronic cough include:
- Chronic Obstructive Pulmonary Disease (COPD – Chronic Bronchitis / Emphysema): The chronic irritation of lung due to smoking causes the airway and lungs to be chronically inflamed. This inflammation causes chronic cough with phlegm and shortness of breath. Smoker’s lungs are more vulnerable to infection than non-smoker lungs.
- Asthma: Asthma can also cause sporadic dry cough. This could be a sign that your asthma is not yet fully controlled. Sometimes cough only happens in specific locations, such as workplace or school.
- Medications: ACE inhibitors (medications for elevated blood pressure) can cause dry cough. Some of the common ACE inhibitors are lisinopril, captopril, enalapril and ramipril.
- Chronic lung infections: Some lung infections can cause chronic cough. Tuberculosis, a highly contagious lung infections, can cause fevers, night sweats, and cough, sometimes with blood (hemoptysis).
- Lung Cancer: Cancer originating in the lung or spread from other organs can cause cough, sometimes with blood (hemoptysis). Unintentional weight loss is also seen is some patients.
Risk factors for developing cough are:
- Cigarette smoking: Current or former smoking is a major risk factor for chronic cough. This is caused by direct inhalation of cigarette toxins or second-hand smoking (breathing cigarette toxins in the air).
- Exposure to someone with respiratory infections: Respiratory infections could be very contagious.
- Allergies: People with allergies have an increased risk of developing cough when exposed to a specific allergy trigger.
- Environmental: Some work places could have irritants in the air that one can breathe in and develop cough. High pollution areas or using coal for cooking or heating can also increase your risk of cough.
- Chronic lung diseases: People with asthma, bronchiectasis (enlarged airways), COPD and previous lung infections with scars are at increased risk of developing cough.
- Female gender: Women have a more sensitive cough reflex increasing their risk of developing chronic cough.
When to See Your Doctor
Your health-care provider should see you if you have persistent cough. The causes of cough could be many and treatments quite different.
Call 911 immediately if you have sudden onset of cough associated with:
- Severe difficulty breathing
- Swollen face and hives
- Severe chest pain
- Coughing blood (or hemoptysis)
Call your physician if you developed cough and:
- Have recently been exposed to a patient with tuberculosis or whooping cough.
- Have shortness of breath
- Have fever
- Have bloody phlegm or phlegm with pus
- Have new wheezing or wheezing that doesn’t resolved with inhalers
- Have worsening leg swelling and shortness of breath especially when laying flat.
Diagnosing and Treating Cough
Many diseases, non-severe or severe can cause cough. Cough suppressant medication may help control the cough but the reason for it hasn’t been addressed yet. Your physician will work with you in finding the reason for your cough, as well as the best treatment.
What to Expect
Most of the cough episodes are self-limited and disappear after a respiratory infection is resolved with our without specific treatment. Cough that persists will need medical attention.
One of the most important things when dealing with cough is to determine if an acute serious disease causes the cough or not. Luckily, the vast majority of acute cough causes are benign upper respiratory track infections, such as common cold.
Warning signs associated with cough that may indicate an acute severe disease include:
- Shortness of breath
- Chest pain
- Rash / facial swelling
- Coughing up blood (hemoptysis)
- Rapid breathing
Your doctor will obtain a detailed history and perform a physical exam to find out the cause of your cough, then order any necessary tests and initiate treatment. Remember to keep a record of your cough, and bring the list of all the medications you are taking, including over-the-counter medications and supplements.
How It’s Diagnosed
Your doctor will ask you questions about your cough and lifestyle:
- When did your cough start?
- Does your cough bring up phlegm?
- If there is phlegm, what’s the consistency and color? Is there any blood?
- What triggers your cough?
- Have you been in close contact with people with any respiratory infections, such as common cold, tuberculosis, pneumonia, or whooping cough?
- What medical illnesses do you have?
- Do you have any allergies?
- What do you do for living? What’s your work place like?
- What do you do in your time off? Have you recently travelled?
- Do you smoke cigarettes or marijuana? Do you use recreational drugs?
At the doctor’s office, they will take your vital signs, including your temperature. They will check your oxygen levels by attaching a small painless clip to your finger. Your doctor will look at the back of your throat and ears, when necessary. They will listen to your lungs and heart with a stethoscope and will also look at your legs and skin.
Your doctor may or may not need to order some tests:
- Chest x-ray: quick and easy chest picture.
- Blood sample: to see if your body is fighting an infection.
- CT scan of the chest: a better quality picture of the chest.
- Throat swab: usually done with a long cotton swab.
- Phlegm sample: collected after a deep cough.
- Spirometry: you will be asked to breathe out hard and fast into a small plastic device to measure how good you breathe out air.
- Bronchoscopy: a procedure where a camera is passed through your throat to your airway and lungs.
- Methacholine challenge test: a standard asthma breathing test often used to assess for cough-variant asthma.
How It’s Treated
The treatment of your cough will change depending on what is causing it:
- Upper Airway Respiratory Infections: Anti-inflammatory, anti-fever and expectorant medications help decrease symptoms while one recovers from the infection. Antibiotics are rarely needed. Viruses most commonly cause these infections. When a bacterial infection such as streptococcal pharyngitis or whooping cough is suspected, antibiotics are indicated.
- Allergic rhinitis: Treatment includes nasal steroids and antihistamines/decongestants. It is important to avoid the allergy trigger, if known, when possible.
- Post-nasal drip: Antihistamines/decongestants are the best initial approach.
- Asthma attack and COPD exacerbations: Usually treated with inhalers designed to open the airways called bronchodilators and a short course of steroids such as prednisone. Your physician will decide if antibiotics are also needed. Stop smoking always helps.
- Acid-reflux: Anti-acids, H2-blockers (stomach acid reducers) and proton inhibitors (stomach acid blockers) are used for treatment.
- Pneumonia: Treated with a single or a combination of antibiotics.
- Lung clot: Treated with blood thinners.
- Collapsed lung: Treatment requires the insertion of a plastic tube in the chest to allow for the re-expansion of the lung.
- Tuberculosis: Treated with a combination of antibiotics, serial phlegm samples and initial respiratory isolation until no longer contagious.
- Heart Failure: Treated with diuretics, medications that help dry the lungs.
- Lung Cancer: Chemotherapy, radiation and removal are potential treatments depending on the location and stage of the cancer.
- ACE inhibitors-induced cough: Treatment includes discontinuation of medication and use of alternative anti-elevated blood pressure medications.
Living With Cough
Cough is a very common symptom in daily living. Most of us have and will have episodes of persistent cough through our lives. Although a normal reflex when sporadic, persistent cough could be very disturbing during our daily activities.
What to Expect
Most causes of acute persistent cough resolves as the cause is treated. When cough persists for long periods of time, it will have a bigger impact in your quality of life:
- It could be exhausting and decrease your energy to face daily activities.
- It could be disruptive at night and cause sleeplessness to you or your significant other.
- It could cause headaches, nausea, and even vomit.
- It could cause chest wall and muscle ache.
- It could cause broken ribs, especially in the elderly.
- It could cause or worsen urinary incontinency.
- It could cause sore throat and hoarse voice.
- It could interrupt normal eating and/or drinking.
- It could need physical isolation if it’s due to a contagious disease.
- It could have psychological effects by feeling embarrassed of one’s persistent cough
- It could make patients feel restricted in social events.
- It could cause frustration, anger, anxiety, and depression.
Managing a Cough
Few tips that could help you manage your cough while your physician is treating the cause:
- If cough is due to a contagious disease, it is important to take action and avoid being contagious to others.
- Remember that 3000 droplets of saliva are expelled every time we cough so the risk of be contagious to others is high when we cough.
- Avoid visiting public places when having a contagious infection.
- Avoid shaking hands when having a respiratory infection.
- Wash your hands frequently with hot water and soap for 15 to 20 seconds. Alcohol-based rubs are a good alternative.
- Cover your mouth and nose with a tissue when coughing or sneezing, disposing of the tissue right away. If there is no tissue available, cough into your upper sleeve or elbow and not your hand.
- Avoid touching your eyes, nose, and mouth when having cough due to an infectious disease.
- Clean and disinfect surfaces you touch at home or work when sick.
- Stop smoking at any time is a great way to help control your cough. Stay away from people who smoke to avoid second-hand smoking.
- If there is any specific irritant in the air causing you to cough in your house or workplace, try to avoid them.
- If your cough is due to a specific allergy triggers try to avoid it. For example, if you suffer from hay fever due to pollen, avoid being outside when levels of pollen are high. Check your weather report on a daily basis. You can also wear respiratory protective gear approved by your physician.
- An air vaporizer or a steamy shower helps decreasing nasal congestion and soothe the throat and airway that are chronically irritated from persistent coughing.
- Work with your physician. The treatment of cough is not only tailored to the cause but to the patient’s lifestyle.
- The use of cough drops and hard candy increases saliva production and helps relieve dry cough and sore throat. You should never give them to children under the age of three because of the risk of choking.
- Honey: It soothes an inflamed throat and may reduce the cough frequency. It should not be given to children under the age of 1 due to high risk of botulism, a serious infection.
You don’t need to deal with your persistent cough by yourself. Your physician and the medical staff are a great supporting system available to you. They will provide you with the information you need. Many times, a multidisciplinary team of health-care providers will be needed to help you deal with your persistent cough. Ask them questions. Join local support groups.
Once the reason for your cough has been identified, learn more about the specific disease that is causing you to cough.
Here are some useful links for reference:
Learn how to cover your cough:
Learn more about your cough:
Learn more about the different causes of cough:
Join a support group:
Questions to Ask Your Doctor About Cough
Write down any questions you may have for your doctor, so you won’t forget to ask them when you meet them during your visit.
1. Is my cough ever going to go away?
Most of the time, a cough will go away on its own over the course of days or weeks. If your cough persists, your physician may need to perform some tests to identify other less common causes of cough. Depending on what the cause is of your cough, treatment of chronic cough will help make your cough better and sometimes completely resolve it. There are some patients where chronic cough will persist despite adequate treatment.
2. What warning signs should I be aware of when having cough?
It should be brought to your doctor’s attention any time your cough is associated with high fever, shortness of breath, new phlegm production, or change in the color or quantity of the phlegm you normally produce every day. Coughing up blood is another important finding and may indicate a serious illness. Sudden onset of cough and shortness of breath with or without chest pain needs immediate medical attention.
3. Do I need antibiotics to treat my cough?
Respiratory infections can make us cough. Most of the time, those infections are caused by viruses, such as the common cold. Those infections do not require antibiotics. In a minority of cases, bacteria can cause infections. If that is the case, your doctor will evaluate when and which antibiotics you need.
4. Is my cough contagious?
Cough could be contagious when it is caused by an infection that spread though the air when sneezing or coughing. Not all infections of the airway and lung are contagious but many are. When having a respiratory infection, remember to cover your nose and mouth with a tissue when coughing or coughing to your upper sleeve. Your doctor can give you further information regarding when you are not contagious anymore depending on the type of infection.
5. How serious is my cough?
Most causes of cough are benign and self-limited. A persistent cough with other symptoms such as shortness of breath, phlegm production, rapid breathing, chest pain, or wheezing could indicate an underlying disease that needs the immediate attention of your doctor.
6. Will my cough go away if I stop smoking?
Quitting smoking is always good for your airway and lung no matter when you do it. Quitting can improve your cough and sometimes make it disappear. Even if smoking has chronically damaged your lungs and makes you cough every day, quitting smoking will always improve your cough.
7. Is it a good idea to take medication to suppress my cough?
Cough is an important reflex. It is a defense mechanism used by your body to keep your airway and lungs clean of particles, microbes, irritants, dust, and mucus. More important than just suppressing your cough is to find out why you have persistent cough. Once the cough cause is detected and treatment is started, cough-suppressant medications may help decrease the intensity and frequency of cough.
Mauricio Danckers, MD, FCCP
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