Thick, Sticky Mucus: Symptoms, Causes, and Treatment (2023)

Thick, sticky mucus or phlegm, also known as catarrh, is a symptom that often results from infection in the nasal passages, sinuses, lower airways, or lungs. It may be associated with a wide range of conditions (not limited to infection), including the common cold, asthma, sinusitis, pneumonia, and cystic fibrosis.

Commonly associated symptoms include fever, cough, shortness of breath, and fatigue, based on the cause. This article will discuss the symptom of thick, sticky mucus, common causes, when to see a healthcare provider, diagnosis, and treatment.

Thick, Sticky Mucus: Symptoms, Causes, and Treatment (1)

Symptoms of Thick, Sticky Mucus

In the presence of an infection, allergen, or irritant, your body may make larger amounts of mucus to help trap foreign invaders. But high amounts of mucus can clog the airways in your nose, throat, lungs, and sinuses, making breathing difficult.

It can also cause you to cough, a common symptom of thick, sticky mucus. If you have an increased amount of mucus, you may cough up white, green, or brownish sputum.

Thick sticky mucus is rarely an isolated symptom. It may be associated with the following symptoms based on the cause:

  • Fever
  • Chills
  • Cough (a productive cough is when you make so much sputum that you cough up thick yellowish-green or brown sputum)
  • Sneezing
  • Congestion
  • Headache
  • Shortness of breath
  • Chest tightness
  • Fatigue
  • Sore throat
  • Difficulty swallowing
  • Muscle aches
  • Nausea and vomiting
  • Loss of appetite
  • Rash

Causes of Thick, Sticky Mucus

The body's mucous membranes produce mucus. These membranes line your respiratory tract from your nose to your lungs. They also produce mucus in the digestive, reproductive, and urinary systems.

Mucus is important in ensuring your body tissues don't dry out. It also filters out dust, allergens (substances that may trigger an allergic reaction), and microbes.

While a small increase in mucus production is natural at times, the presence of foreign invaders like viruses or bacteria or allergens like pollen can cause the body to overreact and create thick sticky mucus that may clog your throat and nasal passages.

The common cold (a viral infection) and sinus infections (usually viral but may be bacterial or fungal) are common reasons your body may make thicker mucus.

But a host of conditions can cause your body to produce thick, sticky mucus, including:

  • Allergies (pollen, dust, animal dander, allergic fungal rhinosinusitis): Mucus in nose, throat, and/or postnasal drip
  • Asthma: A chronic condition of airways that are inflamed and constricted by various triggers, in which more mucus is produced and mucus plugs may develop
  • Bronchitis: Inflammation of the larger airways
  • Pneumonia: Bacterial or viral lung infection, may cough up green, yellow, or bloody mucus
  • Chronic obstructive pulmonary disease (COPD): Progressive inflammatory disease of the lungs, includes chronic bronchitis and emphysema
  • Bronchiectasis: Permanent widening of the airways, leading to problems clearing mucus
  • Lung cancer: Cough and coughing up blood or rust-colored sputum
  • Smoker's cough: From chronic smoking, may cough up black or brown mucus
  • Cystic fibrosis: An inherited condition that leads to thick mucus production in the lungs and other organs
  • Amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease): A progressive disease that attacks the nerve cells that control muscles

How to Treat Thick, Sticky Mucus

Treatment of thick, sticky mucus depends on the cause of your symptoms. A healthcare provider will manage the underlying condition and suggest appropriate treatment for chronic conditions, such as allergies, asthma, COPD, or cystic fibrosis.

Most cases of thick mucus are due to respiratory viral infections that are self-limiting (resolve on their own). Treating your symptoms (with advice from a healthcare provider) with over-the-counter (OTC) medications such as pain relievers, decongestants, and expectorants may help you feel better. OTC cough and cold medicines should not be used for children under age 4.

Sleeping in the propped-up position may help you to breathe better at night and alleviate your coughing symptoms. Using a humidifier may also help.

If the cause of your mucus is a bacterial infection (such as some cases of sinusitis, bronchitis, or pneumonia), your healthcare provider may prescribe a course of antibiotics in mild and moderate cases. More severe cases may need intravenous (IV) antibiotics that are administered at a hospital.

Viral infections, like the common cold and most cases of acute bronchitis and sinusitis, usually resolve on their own. They do not require antibiotic medications, which will not work against viruses. Unnecessary use of antibiotics leads to bacteria developing antibiotic resistance, which can mean having an infection later that is hard to treat.

Using antihistamines and washing your bedding regularly can alleviate symptoms caused by allergies to pollen, dust mites, and other allergens.

If you have a rare condition such as cystic fibrosis or ALS, you may develop thick secretions that impact your ability to breathe and swallow. Adequate hydration, coughing exercises, and a portable suction unit may help alleviate your symptoms.

Complications and Risk Factors Associated With Thick, Sticky Mucus

If you have a bacterial infection and are prescribed antibiotics, it is important to complete the full course of antibiotics and not stop early. This helps ensure all of the bacteria are eliminated so you don't have a resurgence of the infection, which can result in worse symptoms and thick mucus.

If you smoke, quitting smoking lowers your risk of respiratory problems such as infections, COPD, emphysema, bronchitis, bronchiectasis, and lung cancer.

Many conditions that cause thick mucus are risk factors for pneumonia, which can be serious or life-threatening. These include asthma, bronchiectasis, cystic fibrosis, and COPD. You are also more at risk for pneumonia if you are age 2 or younger or age 65 or older, have a weakened immune system, smoke cigarettes, are hospitalized, or have a serious condition.

Are There Tests to Diagnose the Cause of Thick, Sticky Mucus?

For mild to moderate symptoms, you can use a thermometer at home to see if you have a fever. If you have a fever for longer than five days, you should check with a healthcare provider.

A diagnosis of the cause of your thick sticky mucus starts with a healthcare provider taking a detailed history of your symptoms and performing a physical exam.

The exam includes taking your vital signs (heart rate, breathing rate, temperature, and blood pressure), listening to your heart and lungs, checking for swollen lymph nodes, and performing a focused head and neck exam, looking for signs of infection.

To determine what might be causing your thick, sticky mucus, your healthcare provider may recommend/perform other tests:

  • Chest X-ray(CXR): A CXR is a relatively quick and accessible imaging tool used to detect the presence of fluid in the lungs.
  • Complete blood cell count (CBC): A CBC measures the amount of red, white, and platelet cells in the blood. Higher numbers of white blood cells (immune cells) may suggest a viral or bacterial infection. The presence of fluid in the lungs on CXR and high white blood cell counts on CBC may indicate the need for a sputum culture.
  • Sputum culture: A sputum culture is a laboratory test that checks for bacteria-causing infections in the respiratory tract. It is frequently used in the diagnosis of pneumonia, tuberculosis, and bronchiectasis.

When to See a Healthcare Provider

If your symptoms were initially those of a common cold and they last for 10 days or more, get better and then worsen, or you have other health conditions that worsen, contact a healthcare provider.

High fever, chills, malaise, chest tightness, productive cough, or trouble breathing are ominous signs that may indicate the presence of a serious problem that requires immediate medical attention.


Viral and bacterial infections are two common causes of thick sticky mucus, which can clog your airways, causing you to cough and have trouble breathing. Viral respiratory illnesses usually resolve on their own. OTC medications, like decongestants and expectorants, may provide relief from symptoms.

If your symptoms of thick mucus last for more than 10 days, contact a healthcare provider for advice, diagnosis, and treatment.

A Word From Verywell

When you are having thick nasal or sinus drainage or coughing up mucus, you may feel miserable. Usually, this is a temporary part of a viral illness such as the common cold and will resolve on its own. For other causes, treating the underlying cause of your thick mucus is the best way to resolve symptoms.

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