What Are Mucus and Phlegm? Causes, Symptoms, and Treatment


Do allergies cause phlegm?

Allergies can cause an increase in the production of mucus and phlegm. Allergens such as pollen, pet dander, mold, and dust mites can trigger inflammation in the respiratory system, which triggers increased mucus production. Allergy mucus can be thick and sticky and can cause post-nasal drip.

Get started
Wyndly Allergy

Beat your allergies forever.

Get Started With Wyndly

Even when you're healthy, your body produces mucus, which forms a protective lining in certain parts of your respiratory system. Most people rarely notice mucus when they are healthy because it's thin and less noticeable.

However, exposure to smoke, allergies, and infections triggers the production of excess and thick mucus. At least that's when you notice the mucus and phlegm. While these substances are part of a healthy respiratory system, they can make you uncomfortable and cause breathing difficulties. 

Fortunately, there are ways to reduce mucus and phlegm buildup. Read on to learn more about mucus and phlegm and how to get rid of them.

Difference Between Mucus and Phlegm

Mucus and phlegm are substances your body produces to keep the respiratory system clear of infection and irritants. Mucus is a thinner secretion that is produced by the nose and sinuses. It serves as the regular protective layer of the airways and helps to keep them moist.

On the other hand, phlegm is a thicker substance that is produced in the lower respiratory tract and lungs. Your body produces phlegm in response to inflammation or infection.

For instance, your body will produce phlegm when you have respiratory infections such as sinusitis, flu, or cold. Phlegm is more likely to cause coughing than mucus because it is thicker and can more easily clog the airways.

Why Does My Mucus Change Color?

Have you ever wondered why your mucus changes color from time to time? Your mucus changes color depending on what is happening outside or inside your body. Reasons your mucus changes color include:

  • Exposure to smoke or other pollutants
  • Allergies
  • Infections in your airway
  • Blood in your respiratory system

The next time you notice your mucus changing color, it might be a sign that you need to take some precautions or see a doctor.

Types of Mucus

The best way to classify mucus is according to color and texture. Here are the different types of mucus according to color:

  • Clear: When you are healthy, your mucus will be clear. Hay fever or allergic rhinitis may also trigger the production of a clear nasal discharge.
  • White: The color will change to white when you have allergic sinusitis or a common cold.
  • Yellow: Yellow mucus is a sign of an infection in your airways. The color indicates your body is fighting back since the color comes from white blood cells that rush to kill the invader.
  • Green: The color comes from dead white blood cells and other substances released as your body fights the infection.
  • Black: Black mucus is a sign of exposure to smoke or other environmental irritants.
  • Pink or red: Pink or red mucus can signify blood in the respiratory system. The color may also indicate an infection, such as pneumonia, an injury, or nose bleeding.
  • Brown or orange: Brown or orange mucus is typically caused by dried blood in the respiratory system. You might also notice this color if you inhale something brown, such as dust.

As for texture, your mucus can be slimy or thick, and the underlying cause usually determines this. If your respiratory tract is healthy, your mucosal discharge will be thin and watery. However, if you have an infection, it will be cloudier, thicker, and stickier.

Why Am I Making So Much Mucus?

If you've noticed an increase in mucus production, there are a few possible causes. These include eating spicy foods, dehydration, certain medications, and hormone imbalance. In some cases, excess phlegm can also signify an underlying medical condition such as allergies, asthma, or cystic fibrosis.

The common reasons for excess mucus production are:


Allergic reactions often involve the production of histamine, a chemical that fights foreign invaders in your body. When allergens enter your airways and irritate them, it triggers your immune system to produce excess mucus as a protective measure. You'll have allergy phlegm and other allergy symptoms such as sneezing, itching, and watery eyes.


Bacterial and viral Infections in your airways can cause a change in the color of your mucus and an increase in the amount you produce. The most common infections that cause excess mucus are sinusitis, bronchitis, the common cold, and pneumonia.


Pollution, dust, smoke, and other airborne particles can irritate your airways and trigger excess mucus production. The irritants trigger your immune system to produce extra mucus to flush out the allergens.

Symptoms of Excess Mucus and Phlegm

The symptoms of excess mucus and phlegm vary depending on the underlying cause. However, common symptoms include:

  • A runny or stuffy nose
  • Post-nasal drip (mucus dripping down the back of your throat)
  • Sore or scratchy throat
  • Congestions in the airways
  • A persistent productive cough
  • Wheezing
  • Difficulty breathing
  • Headaches due to sinus congestion

See your doctor if you have any of these symptoms and are concerned about the amount of mucus or phlegm you produce. They can determine the cause and provide the best treatment option for you.

Is It Allergies or a Cold?

It can be difficult to tell the difference between allergies and colds as they have similar symptoms. For instance, both can cause sneezing, congestion, and a runny nose. So how do you know which one you have? Consider the pattern and duration of your symptoms.

Allergy symptoms flare up during a particular time of the year when the substance you're allergic to, such as pollen, is in high concentration.

The symptoms will last long, mostly until the allergy season ends. A common cold lasts seven to ten days and can affect you at any time of the year.

Allergies don't usually cause fever, while a cold can. Allergies come with more itching in the nose, throat, ears, and eyes, but a common cold will rarely cause itching.

You can also tell what you're suffering from based on whether you have body aches or a sore throat. You'll most likely have a headache when you have allergies due to congestion. A cold causes a sore throat and body aches more frequently than allergies do.

How to Get Rid of Excess Mucus and Phlegm

Fortunately, several at-home treatments can reduce the mucus in your respiratory system. These include:

  • Drinking plenty of fluids
  • Use a humidifier
  • Gargle with salt water
  • Use eucalyptus oil
  • Place a warm, wet washcloth on your face
  • Avoid smoke and other irritants
  • Take a hot shower or bath

These remedies will work best if your symptoms are mild and will thin out mucus, making it easier to cough up and clear the airways.

How Can I Prevent Allergy Phlegm?

The best way to prevent allergy phlegm is to avoid allergens. Identify your triggers and try to stay away from those substances. You can also take preventive measures, such as using air purifiers in your home and wearing a face mask when the pollen count is high.

Remember to shower and wash your clothes frequently, keep windows closed during the pollen season, and avoid pets if you’re allergic.

When to See a Doctor

Knowing when to see a doctor for excess mucus and allergies is crucial in preventing further complications. When you have excess mucus, you should see the doctor if:

  • Home remedies and over-the-counter (OTC) medications are not helping
  • You're experiencing shortness of breath or difficulty breathing
  • You have a persistent, high fever, or your cold becomes unusually bad
  • You notice blood in your mucus

In most cases, allergy symptoms disappear once you implement the right preventive measures or use OTC medications. However, you should see your doctor if:

  • OTC medications fail or yield severe side effects like dizziness
  • Your allergies interfere with your daily activities and quality of life
  • You have asthma-like symptoms such as chest tightness and wheezing
  • You're experiencing a severe eye infection or skin rash

Your doctor can diagnose the root cause of your symptoms and provide a more personalized treatment plan.


If allergies are causing excess production of mucus and phlegm, your doctor will likely recommend an allergy test to determine the exact allergens causing your symptoms. Your allergist can use a skin prick test or recommend an at-home allergy test.

Skin Prick Test

The skin prick test involves pricking or scratching your skin with a needle containing small amounts of an allergen. If you are allergic to any substances, there will be redness and swelling at the site of the prick. This method is inconvenient and uncomfortable since you have to go to the doctor's office and withstand the needle pricks. The site of the prick can also result in itchy hives.

At-Home Allergy Test

The at-home allergy test from Wyndly is a convenient option that allows you to test for allergies in the comfort of your home. All you need to do is take a quick finger prick to collect a small blood sample and mail it back to Wyndly for testing. An allergy doctor will interpret your results and create a personalized treatment plan for your allergies.


It's easier to manage excess mucus caused by allergies using various treatment options. Below is a highlight of the most effective allergy treatments:


If limiting exposure and using home remedies are not enough to relieve your allergy symptoms, including excess mucus, you can use OTC for short-term symptom management. Popular OTC medications include:

  • Antihistamines: These medications temporarily block the release of histamine, a chemical that causes inflammation and triggers allergies. Antihistamines can reduce excess mucus and other allergy symptoms.
  • Decongestants: Decongestants can reduce congestion and shrink swollen blood vessels in the nose.
  • Nasal sprays: Nasal sprays can reduce nasal congestion. The most common type of spray is corticosteroid nasal spray, which reduces inflammation in the nasal passages.

If the OTCs don't provide enough relief from your symptoms, allergy immunotherapy might be right for you.

Sublingual Immunotherapy

Sublingual immunotherapy involves placing drops or tablets containing small doses of allergens under the tongue. This goal is to desensitize the body to the allergen over time, thus reducing allergic reactions when you come into contact with the allergen. This is a more effective long-term treatment as it retrains your immune system and helps you live allergy-free.

Take Our Allergy Assessment

If you're looking for long-term relief from excess mucus and other allergy symptoms, let Wyndly help. Our experienced allergy doctors will create a personalized at-home treatment plan to train your body to build immunity to allergens and help you live allergy-free.

Take our online allergy assessment today to get started!

Is Wyndly right for you?

Answer just a few questions and we'll help you find out.

Get Started Today