Too much mucus is a sign of a chronic respiratory condition, acute illness, and some types of chronic obstructive pulmonary disease (COPD). While mucus can be beneficial to the body, producing too much mucus can cause breathing difficulties and infection.
This article explains the causes of excess mucus and how genetics and lifestyle choices can add to the problem.
Common Causes
Mucus is often mistaken for saliva, but the two substances are not the same.
Saliva is fluid produced in the mouth that helps you break down and swallow your food. Mucus lines the tissues while its slippery makeup traps potential irritants. Mucus contains dead cells and debris from the upper and lower respiratory tract, trapping them as well as bacteria so that everything can be coughed up and cleared from the lungs.
Mucus (also called sputum) is produced by goblet cells and submucosal glands. Overproduction or hypersecretion can occur due to dysfunction of these cells, an infection, inflammation, irritation, or debris in the respiratory tract.
People with chronic respiratory illnesses learn to live with increased mucus pretty much all the time. It’s a fact of life. They can also experience acute flare-ups and cough up even more mucus.
Certain conditions are most responsible for triggering mucus production:
Respiratory Infection
Anyone can have a brief bout of a respiratory illness, which can cause increased mucus in the lungs. In fact, acute respiratory tract infections are one of the most common reasons people seek medical care in the United States.
The common cold is a common trigger of viral and bacterial respiratory tract infections. In some of the worst cases, the infections can lead to bacterial pneumonia.
The lungs react to infectious organisms by mounting an immune response to get rid of the infection. Mucus production increases to help destroy invading microorganisms when you have an infection.
In general, the mucus should decrease to normal levels within a few days after your recovery.
Asthma
Asthma is characterized by episodes of respiratory distress that are precipitated by weather changes or by substances such as airborne particles, pollen, and pet dander.
During an asthma attack, you may experience a “hypersecretion” of mucus. Even experts are hard-pressed to define what “hyper” mucus or even “too much mucus” is since it’s assumed that the body produces about 1 liter of mucus per day.
Chronic Bronchitis
Chronic bronchitis, a type of COPD, is associated with excess mucus production in the lungs. The main cause is cigarette smoking.
A diagnosis of chronic bronchitis depends on having a cough with active mucus production most days of the week for at least three months (and for two years). Other lung diseases, such as tuberculosis, must be ruled out.
Mucus can increase even more than usual when bronchitis flares up.
Emphysema and Bronchiectasis
As another type of COPD, emphysema is characterized by increased mucus production, coughing, and a predisposition to lung infections.
Mucus is a clear fluid that lines the nose, mouth, and throat. Phlegm is a type of mucus that is produced by the lungs and lower respiratory tract. The presence of phlegm means that the lungs and airways are irritated. Mucus is usually expelled from the nose; phlegm is usually expelled from the lungs (through coughing).
Bronchiectasis is a disease in which recurrent infections lead to a permanent widening of the airways. It often produces thick, foul-smelling mucus.
Pulmonary Edema
With pulmonary edema, a harmful increase in lung fluid can develop. It can lead to shortness of breath. In fact, difficulty breathing can cause people with pulmonary edema to awake soon after falling asleep, struggling for breath.
Compounded by more mucus than usual, breathing can become even more difficult. The mucus is often frothy in appearance and may have a pink color due to the presence of blood.
Genetics
There are several hereditary conditions associated with increased mucus. Some conditions directly affect the lungs while others impair the muscles involved in breathing, which leads to increased respiratory mucus:
Cystic fibrosis is a genetic disease that affects multiple systems of the body, including the respiratory and digestive systems. Increased mucus is a primary characteristic of this condition. Primary ciliary dyskinesia is a genetic disorder characterized by defective cilia (tiny, hair-like structures). It leads to increased mucus in the lungs and a predisposition to breathing difficulties and infections. Neuromuscular conditions such as muscular dystrophy and spinal muscular atrophy can also lead to excess mucus because they impair muscle function. This, in turn, decreases lung movement when you inhale and exhale and reduces your strength and ability to cough. Then mucus pools in the lower lungs.
Lifestyle Risk Factors
Environmental irritants such as cigarette smoke and pollutants can cause the goblet cells to produce and secrete mucus while damaging the cilia and structures of the airways.
Exposure to these irritants, especially if you already have a lung disease, can substantially increase your risk of excess mucus in the lungs.
Common irritants include:
Indoor air particles (dust or pet hair)Indoor or outdoor fumes or workplace emissionsOutdoor air pollutionTobacco smoke
Summary
Anyone who has ever dealt with a respiratory infection like bronchitis knows that excess mucus comes with the territory. Bronchitis is one of several medical conditions that can trigger this state. So can asthma, pneumonia, and emphysema as well as genetic and environmental factors. If a sharp healthcare provider can identify and treat the underlying cause, mucus production should return to normal.
A Word From Verywell
A cough may seem like “a little thing,” but a persistent cough could be a sign that you have a condition that needs medical attention. So don’t brush it off. It’s smart to consult a trusted healthcare provider when your health may be on the line.
