Is a Cough Contagious?

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

View the Finding Relief for Your Cough Slideshow

What is a cough?

A cough is defined as the act of forcing air through your throat, often followed by short loud noise. Coughing can be a reflexive action to keep respiratory passages free of irritating substances (such as dust, mucous, phlegm, nasal drainage and foreign bodies). Consequently, a cough reflex can be protective mechanism for the individual. There are many types of coughs including:

  • Dry cough: a cough that doesn't produce mucus (also termed a non-productive cough)
  • Wet cough: a cough that produces mucus or sputum (also termed a productive cough)
  • Barking cough: a cough associated with viral illnesses and/or croup especially in young children usually (croup cough)
  • Whooping cough: a cough associated with infection (pertussis); individuals (usually children) produce a whooping sound when they cough
  • Stress cough: reflexive, nonproductive cough that occurs when an individual is under stress
  • Acute cough: a cough that has just begun or has been intermittent, often resulting within a week or so.
  • Chronic cough: a cough that is persistent over time (more than 1 to 8 or more weeks); the timeframe is controversial as health-care professionals and researchers list a variety of time frames to define a chronic cough

Is a cough contagious?

A cough itself is not contagious. Of note, a cough can be a sign of something irritating, impeding, or blocking an airway. But a cough also can be a method of spreading a viral or bacterial infectious disease if the disease is transmitted by airborne droplets. Consequently, people are understandably concerned that coughing is "contagious". However, what is actually contagious is the infecting pathogen, not the cough itself. The transmitted infecting agent may produce the same symptoms, including a cough, in another individual.

Coughing can induce a gagging reflex that, in turn, can produce vomiting. This situation of coughing with vomiting occasionally occurs. Vomiting can be reflexive and is a means to remove irritating material from the body, specifically the contents of the stomach.

Quick GuideTips to Calm Your Cough in Pictures

Tips to Calm Your Cough in Pictures

Whooping Cough Symptoms

Whooping cough is a highly contagious respiratory infection. Symptoms of whooping cough early in the infection are similar to those of the common cold and include:

  • a dry cough,
  • mild fever,
  • nasal congestion,
  • nasal discharge, and
  • sneezing.

How will I know what type of cough I have?

Knowing the type of cough can provide some insight into the underlying cause of the cough.

  • In general, dry coughs and stress coughs are often caused by noninfectious irritants.
  • Some chronic coughs are due to long-term mucus production and/or irritating agents like cigarette smoke.
  • Other coughs are caused by allergies bothering underlying lung disease.
  • Some, but not all, productive coughs are caused by infectious agents as are whooping cough and croup.
  • Coughing up blood or blood mixed with sputum is best evaluated by a health-care professional to determine the underlying cause(s). This combination is usually considered a medical emergency.

The underlying cause of chronic coughs should be investigated by a doctor.

When is a cough no longer contagious?

The answer to this question is tricky. Coughs are not contagious, but certain underlying diseases that produce a cough are contagious, and can be spread by droplets formed during coughing. Correspondingly, when the underlying disease process is no longer contagious, the cough no longer produces infectious droplets.

The key is that coughs are signs or symptoms of underlying problems, and the cough itself is not contagious.

How are coughs spread?

Coughs associated with non-infectious causes (such as dust, chemical irritants and smoking), and are not spread from person-to-person.

Coughs due to infectious diseases may seem like they are contagious and spread to others by person-to-person contact. However, the cough itself may or may not occur in another person with the same infection. If the infection causes cough and other symptoms in another person then, it will seem as though the cough was "spread," but the actual spread of symptoms including cough would be due to the spread of the underlying infection, not the cough itself. So, microbes can be transmitted from one person to another by coughing to produce droplets that carry pass them on.

When should I seek medical care for cough?

In many instances, short-term cough (less than seven days duration) usually requires no medical care. However, the following list of problems associated with a cough should be investigated by a health-care professional:

  • a cough lasting at least a week without improving
  • chills and/or nighttime coughing fits
  • a fever and a cough that lasts at least three or more days
  • a deep cough that produces a lot of mucus and/or bloody mucus

Emergency care should be sought if the coughing includes any one or more of the following:

Coughs can be irritating no matter what type of cough they are. Consequently, people want them to either stop or be markedly reduced. There are many over-the-counter (OTC) drugs and home remedies that can suppress or stop cough, and usually are relatively safe to use to treat acute coughs.

However, individuals that are pregnant and other individuals that have high blood pressure should consult their health-care professional before using coughs treatments. Some treatments may not be advisable or safe.

Individuals that try OTC drugs and home remedies that provide no cough relief should contact their health-care professional to determine if there is an underlying cause that needs treatment before trying to diminish the symptoms of coughing.

REFERENCES:

KidsHealth.org. What Are Coughs.
<http://kidshealth.org/en/parents/childs-cough.html>

Chean, HH, MD. Chronic Cough. Medscape. Updated: Jan 27, 2016.
<http://emedicine.medscape.com/article/1048560-overview>

Bastow, BD, MD. "Teratology and Drug Use During Pregnancy." Medscape. Updated: Jul 18, 2017.
<http://emedicine.medscape.com/article/260725-overview>

Quick GuideTips to Calm Your Cough in Pictures

Tips to Calm Your Cough in Pictures

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Reviewed on 10/4/2017
References
REFERENCES:

KidsHealth.org. What Are Coughs.
<http://kidshealth.org/en/parents/childs-cough.html>

Chean, HH, MD. Chronic Cough. Medscape. Updated: Jan 27, 2016.
<http://emedicine.medscape.com/article/1048560-overview>

Bastow, BD, MD. "Teratology and Drug Use During Pregnancy." Medscape. Updated: Jul 18, 2017.
<http://emedicine.medscape.com/article/260725-overview>

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