What Are the Symptoms of Cystic Fibrosis?

Medically Reviewed by Renee A. Alli, MD on June 01, 2021

Every year, an estimated 1,000 people are diagnosed with cystic fibrosis (CF) in the United States. Since early diagnosis and treatment can give you a better quality of life and help you live longer, it’s crucial to know the symptoms.

What Is CF?

Cystic fibrosis affects the glands in the body that produce mucus and sweat. It creates a build-up of thick, sticky mucus in your organs, which can limit your breathing and cause severe damage to your airways. It affects other parts of your body as well, such as your pancreas, liver, and intestines. CF can also cause fertility problems for both men and women.

You don’t “catch” CF -- you’re born with it due to a genetic mutation that you inherited or a new genetic mutation. Newborn screening can diagnose many babies before they even start having symptoms. Most other cases are found in childhood, but some people don’t know they have CF until they’re adults.

While symptoms vary according to the severity of CF - and may not even be present -- here are the most common symptoms of the disease:

Respiratory Signs

Your respiratory system includes your lungs and nasal passages.

  • Constant coughing. This could be a very “wet” cough that brings up thick mucus (sputum).
  • Shortness of breath.
  • Wheezing. When treated with asthma medicine, your wheezing still may not clear up.
  • Frequent lung infections.Bronchitis and pneumonia are common.
  • Inflamed nasal passages. You could have a stuffy nose that’s not due to a cold or your doctor could find nasal polyps (tissue growths inside your nose and sinuses). Sinus infections may also be frequent.
  • Allergy-like symptoms. Though CF does not make you more prone to allergies, symptoms such as chronic congestion may last all year.

If you have CF, you’ll lose more of your lung function and your respiratory symptoms will most likely get worse as you get older.

Digestive Symptoms

Cystic fibrosis can affect the way your body breaks down food. Signs of this include:

  • Constipation. Very thick poop can stick to the wall of your intestine rather than passing through. This can lead to a blockage, which causes pain, bloating, nausea, and weight loss.
  • Large, greasy stools. Mucus gums up ducts in your pancreas so enzymes that help digest food can’t reach your stomach. Because your body then struggles to absorb fats and proteins, your stool may be “oily,” larger than normal, and foul smelling.
  • Not putting on weight.Failure to thrive” is a common symptom of CF in children. Although they may be eating well, the mucus buildup in their pancreas prevents them from absorbing enough nutrients.
  • Heartburn. Intense coughing makes it more likely that stomach acid will leak into the esophagus. This leads to “acid reflux” or “gastroesophageal reflux disease” (GERD).
  • Diabetes. If the pancreas becomes badly damaged, diabetes can become an issue. This often happens in older children and young adults. Signs include feeling very thirsty, having to pee more than usual, fatigue, and a drop in weight.

Other Signs

Other CF symptoms you could notice include:

  • Sweating a lot.
  • Skin that tastes salty. People with CF have a higher amount of salt in their sweat. You may be able to taste this or see a salty “frosting” on the skin.
  • Problems getting pregnant. Although women with CF produce healthy eggs, they’re likely to have thicker vaginal mucus, which makes it harder to conceive. In most men who have CF, the tubes that carry sperm are blocked with mucus.
  • Leaking urine. Intense, long periods of coughing caused by CF can cause pee to leak out of your bladder. Doctors call this “incontinence.” This may also happen when you sneeze or laugh. It affects women and girls with CF more than men.
  • Joint pain. Most common in large joints like the knees, ankles, wrists, and shoulders, this type of arthritis may come and go. It could also get worse when you have an infection or during periods of illness..

If you or a loved one have any signs of CF, talk to a doctor. You may need to be tested and start treatment right away.

Show Sources


National Heart, Lung, and Blood Institute: “What is Cystic Fibrosis?” “What are the Signs and Symptoms of Cystic Fibrosis?”

American Lung Association: “Cystic Fibrosis Symptoms, Causes and Risk Factors.”

Cystic Fibrosis Foundation: “About Cystic Fibrosis,” “Use the Right Gastrointestinal Medications.”

Mayo Clinic: “Cystic Fibrosis.”

Cystic Fibrosis Trust: “Urinary Incontinence Fact Sheet -- March 2013,” “Additional Complications.”

KidsHealth: “Cystic Fibrosis.”

NHS: “Symptoms of Cystic Fibrosis.”

Cleveland Clinic: “Cystic Fibrosis.”

Johns Hopkins Cystic Fibrosis Center: “Effects of CF: Pancreas/Gastrointestinal Tract: Intestinal Problems.”

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