What Are Common Causes of Thick Mucus?

Mucus in the human body serves many vital functions. Most importantly, mucus protects the body from harmful substances by acting as a barrier and by facilitating the removal of such substances. The presence of thick mucus is often an indication that the body is fighting infection, trying to rid the body of harmful substances or responding to the ingestion of certain foods.

For animals in the vertebrate phylum, mucus is produced by mucous membranes that are located in various places within the body of the animal. In humans, mucous membranes are located on cavities of the body that come into contact with the outside world. These include the nostrils, mouth, ears and genitals.

Mucus is made of water, carbohydrates, proteins, cells and salt, and it serves many important functions for the human body. Mucus protects organs by acting as a barrier that prevents any foreign matter from making its way into the body. For example, mucus in the nasal cavity traps allergens and dust particles before they can make their way into the lungs. This helps prevent humans from inflammation or infection that can be caused by common irritants such as smoke, mold and many bacteria and viruses.

In carrying out its protective function, mucus also removes harmful particles. Thus, when the mucous membranes come into contact with an infectious agent such as a bacteria or virus, they begin to increase mucus production to increase the efficiency of removal. This results in the production of thick mucus. For instance, when the nose is infected with the common cold virus, the nasal and sinus membranes increase the production of mucus in order to remove the virus from the body, thus resulting in the thick nasal mucus commonly experienced during a cold.

The same phenomena takes place when the body comes into contact with an allergen. For many people who suffer from allergies, the presence of the trigger allergen on their mucus membranes causes an increase in the production of mucus, resulting in thick mucus meant to eradicate the pollutant from the body. Increased mucus production can occur in any part of the body that has mucous membranes and comes into contact with an allergen.

In some people, thick mucus can be the result of a food sensitivity or allergy. This is often the case with dairy products. Many times, the fat in dairy products increases the viscosity of mucus, and some people notice an increased amount of thick mucus in their nasal passages and lungs shortly after consuming these foods.

The human immune system protects the body from potentially harmful substances in its environment. The skin, or epidermis, is the largest organ of immunity and serves as a physical barrier between the internal organs and the outside world. The delicate skin that covers the body's orifices is especially vulnerable as it comes into contact with its surroundings. The surface of these openings is covered with a layer of highly specialized epidermal cells that produce a substance called mucus, which acts to protect the inside of the body from outside invasion.

Typically, mucus is a slippery liquid, but occasionally it becomes thicker in response to some form of aggravator to the body. The effect is similar to an oyster reacting to the introduction of an irritant inside its shell.

When the body comes into contact with an allergen, the resulting histamine release causes an increase in mucus production. The purpose of the mucus is to coat and protect the body's vulnerable membranes, especially the nasal passages, where allergens most commonly enter. Sneezing, caused by histamine release, also keeps allergens from penetrating beyond the mucous membrane.

Bacterial and viral pathogens pose a threat to health. To prevent infection, the immune system responds to microscopic invaders by increasing mucus production. The thick barrier of mucus traps harmful infectious organisms and eliminates them.

Mucus also performs the important task of keeping the tissues hydrated. Dry, cracked membranes are more susceptible to infection. While the thicker mucous layer is intended to protect and heal, it can also cause negative symptoms. Inflammation of the nasal passages causes swelling and an increase in mucus production, leading to congestion. When infection occurs in other parts of the respiratory tract, such as the pharynx, phlegm becomes thicker. The body's response is to cough, bringing the substance up and out of the body. If coughing fails to clear the phlegm, the person can develop chest congestion.

Foreign objects can be irritating to mucous membranes. Smoke commonly causes the nasal passages and conjunctiva of the eye to become inflamed. Small airborne particles, such as sawdust or pollen, also may irritate sensitive tissues. Chemical fumes can be strong enough to inflame mucus membranes. Production of mucus increases in these situations in an attempt to lay down a protective coating to soothe tissues and prevent damage.

When the body lacks adequate hydration, slippery mucus becomes thicker. The body's fluid reserves are depleted, and mucous membranes dry out. Thinner secretions, like tears, are no longer produced, leaving only the thickest, most viscous forms of mucus.

Extremely arid climates can have the same effect on the body. Spending time in a warm indoor environment in which the central heating system is running may also contribute to a parched feeling. Although the thickened mucus may feel unpleasant, it actually functions to protect the mucous membranes from completely drying out.

Certain medications may cause a thickening of mucus. Prescription drugs intended to treat depression and anxiety are known to have this effect. Blood pressure pills can raise the viscosity of mucus. Even over-the-counter nasal decongestants, which many people use to combat symptoms of the common cold or flu, have an unpleasant side effect of making mucus more rubbery.

Some people claim dairy products make mucus thicker. The truth is these foods and beverages contain saturated fat, which produces a lingering slick feeling inside the mouth, like a coat of wax. Another possible explanation to support the notion is that those who are allergic to dairy may experience an increase in mucus production in response to these substances. Histamine release increases mucus production even when the allergy is not airborne. Fortunately, dairy-lovers don't have to miss out on their favorite foods and beverages altogether. Here are some suggestions for avoiding the unpleasant thick mucus sensation associated with dairy:

Allergy sufferers know exposure to allergens causes symptoms that interfere with daily life, so they reach for a treatment to soothe their overreactive immune systems. Antihistamines are intended to counteract the body's immune response. They do this by slowing the production of mucus and alleviating the inflammation that leads to tearing eyes and sneezing. With antihistamine use, the watery post-nasal drip type of secretions tend to dry up, leaving only the thicker mucus to do the job.