Signs and Symptoms of Cystic Fibrosis

Medically reviewed by Susan Russell, MD

Cystic fibrosis (CF) is a rare, inherited (genetic) condition primarily affecting the lungs and digestive system. Normally, the protective mucus lining the body's airways, tissues, and organs is thin and slippery. With cystic fibrosis, a gene mutation causes the body to produce thick, sticky mucus that can build up, clog the airways, and cause symptoms such as coughing and difficulty breathing. The mucus also blocks pancreatic ducts, interfering with digestion and nutrient absorption.

Symptoms of CF typically develop in infancy or early childhood and include salty-tasting skin, clubbed (enlarged) fingertips and toes, greasy, loose stools, frequent infections, chronic coughing and wheezing, and breathing problems. CF is a progressive disease, causing chronic inflammation that damages the lungs, pancreas, and other organs over time.

In the past, many born with CF died in childhood due to complications of the disorder. Thanks to recent advancements in treatments, most people with CF can now expect to live well into adulthood.

Respiratory Symptoms

Most people with cystic fibrosis experience respiratory symptoms because the mucus lining their airways is thick and sticky, making breathing difficult. Over time, thick mucus causes inflammation that damages the airways and lungs, causing scarring (fibrosis).

Common respiratory symptoms associated with CF include:

• Persistent cough: A chronic, productive (wet) cough that produces mucus or blood.

• Wheezing: A whistling sound made when breathing, especially during exhalation. Many people with CF experience occasional or frequent wheezing when their airways narrow due to inflammation or the mucus blocking them.

• Shortness of breath (dyspnea): An uncomfortable feeling of not getting enough air, which may worsen during physical activity.

• Frequent respiratory infections: People with CF experience frequent respiratory infections (e.g., bronchitis, pneumonia) because thickened mucus traps bacteria and creates an ideal environment for bacteria and other germs to thrive.

• Nasal polyps: Up to 86% of people with CF develop nasal polyps, which are soft, painless, noncancerous growths that develop on the lining of the nose or sinuses. These teardrop-shaped growths likely grow due to chronic inflammation and excess mucus. They can cause increased nasal congestion, facial pressure, and a decreased sense of smell.

Digestive Symptoms

Thickened mucus can affect the digestive system of people with CF, especially the pancreas. The pancreas produces enzymes that help you digest food. Thick mucus can clog the pancreatic ducts, blocking the flow of digestive enzymes from the pancreas to the small intestine. Thick mucus in the gastrointestinal system can also prevent the passage of food through the digestive tract and block bile ducts in the liver, interfering with the digestion and absorption of fats.

Digestive symptoms common in people with CF include:

• Meconium ileus: Meconium is a dark, tar-like stool most newborns expel within 24 hours after birth. Meconium ileus occurs when a newborn baby's first bowel movement is too thick and sticky to pass, causing a blockage in the last section of the small intestine (ileum). Up to 20% of babies born with CF experience meconium ileus.

• Malabsorption: About 90% of people with CF have blockages in the pancreatic ducts, which impair the absorption of essential nutrients such as carbohydrates, fat, and protein. As a result, people with CF often have malnutrition and poor growth despite eating enough food.

• Bulky, greasy stools: Blockages in the pancreatic ducts prevent digestive enzymes from reaching the small intestine. Undigested foods and fats can lead to loose, greasy, floating stools.

• Constipation: Thick mucus in the digestive tract and too few digestive enzymes can impair the normal digestion of foods, leading to chronic constipation, bloating, and gas.

• Abdominal discomfort: Stomach pain, cramping, bloating, and gas are common in people with CF due to digestive difficulties.

• Gallstones: Gallstones are hard, pebble-sized deposits of bile and cholesterol that can form in the gallbladder (a small, pear-shaped organ that stores bile) when thick mucus blocks gallbladder ducts, preventing it from emptying. Gallstones can cause intense pain in the upper right abdomen.

• Acid reflux: Many people with CF have gastroparesis, which causes your stomach to empty its contents more slowly than usual after eating. When this occurs, the stomach contents can flow back up the throat, causing acid reflux (heartburn).

Other Symptoms

Cystic fibrosis can also affect body parts and systems outside the respiratory and digestive systems. Other signs and symptoms of CF include:

• Clubbing: Clubbing is a term that describes the abnormal enlargement of fingertips and toes. In CF, low oxygen levels in the blood or malabsorption can cause the fingers and toes to enlarge, and the fingernails and toenails may become rounded and curved.

• Delayed growth and puberty: Nutrient malabsorption and poor lung function can hinder proper growth in children with CF. Children with CF may be shorter and weigh less than their peers. Delayed puberty is also common.

• Salty skin: People with CF often have higher-than-normal salt levels in their sweat, causing very salty-tasting skin.

• Infertility: In people assigned male at birth, CF can cause a congenital absence of the vas deferens, the tube that carries sperm from the testicles to the urethra. Though men with CF produce sperm, it does not reach the semen and cannot lead to pregnancy without assisted reproductive technology. In people assigned female at birth, thick cervical mucus can make it difficult for sperm to reach the egg, and malnutrition may cause irregular ovulation.

• Muscle and joint pain: CF-related complications, such as chronic infections, nutritional deficiencies, and inflammation, can contribute to muscle weakness, pain, and joint pain.
  

Symptoms in Children

About 40,000 people in the United States live with cystic fibrosis. Thanks to newborn screening programs, most babies born with CF receive a diagnosis within the first few weeks of life. The process typically involves a simple "heel prick" test, which involves collecting a small amount of blood from the newborn's heel and sending it to the lab for analysis to look for specific genetic markers or mutations associated with CF.

Symptoms of CF in children are similar to those in adults and can vary from person to person. Some of the most common CF symptoms in children include:

• Coughing that produces mucus

• Salty-tasting skin

• Slow growth, even when eating sufficient amounts of breastmilk/formula/food

• Meconium ileus

• Shortness of breath

• Frequent respiratory infections

• Nasal congestion

• Delayed growth and puberty

• Loose or greasy bowel movements

When to Contact a Healthcare Provider

If you or your child have a family history of cystic fibrosis and/or are experiencing symptoms of the condition, see a healthcare provider and request an evaluation. Common symptoms include:

• Shortness of breath or difficulty breathing

• A persistent cough that produces mucus or blood

• Loose, greasy stools

• Constipation

• Frequent respiratory infections

• Wheezing

• Difficulty gaining weight or delayed growth

Keep in mind that cystic fibrosis is rare and most people with it are diagnosed early in life. However, newborn screening for CF only became common practice in 2010. Although unlikely, it is possible that you were born with CF and were never diagnosed.

Seek immediate medical attention if you or a loved one with cystic fibrosis experiences any of the following symptoms:

• Worsening of symptoms, such as worsened coughing or wheezing, chest congestion, or mucus that changes color (e.g., from clear to green)

• Loss of appetite

• Fever

• Coughing or spitting up blood

• Sudden chest pain or sudden shortness of breath

Questions to Ask Your Provider

Asking questions during visits with your healthcare provider is the best way to ensure you get the information you need. Whether you are facing a cystic fibrosis (CF) diagnosis or living with the condition and want to learn how to manage it well, consider asking your healthcare provider: 

• Could my symptoms (e.g., chronic cough) be due to another condition?

• What treatments can help manage my symptoms?

• What tests do I need to get a cystic fibrosis diagnosis?

• If I have CF, will my symptoms get better or worsen over time?

• What lifestyle modifications can help me manage my symptoms? 
  

A Quick Review

Cystic fibrosis (CF) is a rare genetic disorder that affects multiple organs and body systems, including the lungs and digestive system.

With CF, a gene mutation causes the body to produce thick, sticky mucus that can clog the airways and lead to difficulty breathing, frequent respiratory infections, and a persistent cough. It can also cause digestive symptoms, including loose, greasy stools, constipation, stomach pain and cramping, and malabsorption of nutrients. Delayed growth and puberty, clubbing of the fingers and toes, infertility, and salty-tasting skin are also common symptoms of CF.

With early diagnosis and treatment, people with CF can manage their symptoms and expect to live fulfilling, healthy lives.

Frequently Asked Questions

At what age do cystic fibrosis symptoms start?

Cystic fibrosis (CF) symptoms typically start in infancy or early childhood. However, the age of symptom onset can vary, with some people showing signs shortly after birth while others may not develop symptoms until adolescence or adulthood.

How long can you go without knowing you have cystic fibrosis?

How long you can go without knowing you have cystic fibrosis depends on the severity of your symptoms. If you have mild symptoms, you may live many years without knowing you have the condition. Most people with CF receive a diagnosis by age two, but sometimes, people do not develop symptoms until later in life and receive a diagnosis in adulthood.

Who is most likely to get cystic fibrosis symptoms?

Cystic fibrosis is an inherited condition that requires both parents to pass on a mutated CFTR gene to their child for a child to develop the disease. CF is most common in white people, with about 1 in every 3,500 white newborns born with the condition. Other ethnic groups have lower rates of CF, with about 1 in every 17,000 Black newborns and 1 in 31,000 Asian-American newborns born with CF.

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