Cystic fibrosis is caused by genetic changes and is always present at birth. Although rare, cystic fibrosis isn’t diagnosed in some people who have mild symptoms until they’re adults. This is known as adult onset cystic fibrosis.

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Cystic fibrosis (CF) is a genetic condition that affects the CTFR gene. The condition affects around 35,000 people in the United States.

People with CF may experience damage to their internal organs due to mucous blockages and inflammation. The complications of CF can be serious for children who aren’t receiving treatment, so screening for the condition usually occurs when babies are born.

It’s rare for CF to be diagnosed in a person after 2 years old, but it can happen, especially if you didn’t experience any of the signature CF symptoms during childhood.

When CF is detected later in life, it’s called “adult onset CF.” The causes, diagnosis, and risk factors for adult onset CF aren’t that different from childhood CF.

Learn more about cystic fibrosis.

CF can be diagnosed in adults, though it’s considered unusual.

Data on this subject is limited, but an analysis of data from Italy indicated that, as of 2018, 12.54% of people had a condition diagnosed as CF when they were more than 18 years of age. The average age at the time of CF diagnosis for this group was 36.2. The analysis says that in the majority of these people, male infertility is what led to the diagnosis.

Reasons CF may be diagnosed later in life include the following factors.

Limited access to medical care

A person who didn’t have consistent access to medical care during childhood may find out later in life that they have CF. If you were born in a country where genetic testing isn’t a typical part of prenatal care, or if you grew up in a situation where your caregiver couldn’t take you for regular checkups, it’s possible that your CF went undetected.

Mild symptoms

CF can cause sticky mucous blockages that lead to lung infections and other complications, and it can also cause damage to your internal organs.

It’s possible that during your childhood and adolescence, these symptoms never appeared in a way that concerned the people around you. Some people simply have milder CF symptoms throughout their lifetime, even without treatment.

Unknown family history

People with CF have genetic changes that they inherit from both parents, but you may also inherit one gene for CF from only one parent. If this happens, you probably don’t have CF, but you’re what’s called a “carrier” of that gene and may pass that gene on to children you have.

People who know their family history will usually be aware of people related to them who had CF, and this will be a flag to any healthcare professional that there’s a possibility you may have the genes for CF. If you were adopted or didn’t grow up in a home with your birth parents, you may not know about CF in your genetic history.

Prenatal testing for CF carrier status

Prenatal genetic testing to see if you’re a CF carrier is available and generally offered during prenatal care. A CF test may be performed from a sample of your blood, spit, or tissue from the inside of your cheek.

If you’re pregnant, ask a healthcare professional about CF testing. People who have CF have a 50% chance of having a child with CF and a 50% chance of having a child who is a carrier of CF with each pregnancy, depending on if their partner has CF or is a carrier of the genes for CF.

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Environmental flare-up

CF symptoms are rarely static, but there are periods of intensity, called “flare-ups,” that can be activated by triggers to which you’re exposed.

You may have never had a serious flare-up of your CF symptoms until later in your life. Exposure to dust, allergens, chemicals, or smoke may cause you to experience a flare-up and to seek medical attention for it, leading to a later diagnosis of CF.

When you have CF, the mucus your body makes has more salt than it would normally. Excess salt makes the mucus more sticky and less slippery in consistency. The symptoms of CF in adults and children are mostly caused by this phenomenon.

Common symptoms of adult onset CF include:

Adult onset CF is a genetic condition, and it’s caused by the same genetic mutation that you had when you were born. This is true even if your symptoms aren’t recognized until later in your life.

People who have CF have higher levels of chloride in their sweat. A “sweat test” may be performed to diagnose the condition in an adult. This test is performed by applying a chemical to your skin that causes you to sweat. The sweat is then collected, and the chloride levels are measured.

If the test result is positive for CF, the diagnosis may then be confirmed through genetic testing.

Other tests to diagnose CF may include imaging tests (such as CT scans) and lung function tests.

The treatment for adults who have CF typically includes the following options.


  • Antibiotics: Antibiotics are medications for people with CF to manage respiratory infections.
  • Anti-inflammatory drugs: Anti-inflammatory drugs may be prescribed to improve your lung function.
  • Bronchodilators: Bronchodilators can be used to help open airways.

Medications may also be administered by a nebulizer to help thin respiratory mucus.

Airway clearing techniques

Breathing exercises, chest physical therapy, and medical devices that promote the removal of mucus from the airways are part of daily life for people with CF to maintain their lung function.


If CF has significantly compromised your lung’s efficiency, surgery may be the recommended option. People with CF sometimes need a lung transplant.

Adult onset CF is a genetic condition, which means that there isn’t anything you can do to change your risk of getting the condition.

There are some people who are more likely to have CF. People of Northern European descent seem to be at the highest risk of having CF, though people with any background can have the condition.

If you’re aware of someone on either side of your family who has or had CF, that’s also considered a risk factor.

The life expectancy for people with CF continues to increase dramatically. Innovations in treatment and new medications have made the median life expectancy 48.4 years in the United States, which is a number that’s significantly influenced by the number of children who don’t survive past childhood with the condition.

It’s no longer unusual for people with CF to live into their 50s or beyond.

It’s important to note that CF does cause other health complications, such as liver disease, lung damage, and nutrient malabsorption. If you were living with CF for many years without monitoring or a treatment plan, it’s possible that these complications have gone undetected and could effect your long-term outlook for living with CF.

How can cystic fibrosis go undetected during childhood?

People with milder CF symptoms, people who don’t have access to medical care, and people who are considered at low risk of CF because of their ethnicity or family history may not have their CF diagnosed early in life.

Are there unique complications for people with adult onset cystic fibrosis?

People who don’t show symptoms of CF until later in life may simply have milder CF symptoms, which could mean that their risk of complications is lower. Unique risks for adult onset CF are best discussed on an individual basis with a healthcare team.

What are the treatment options for people with adult onset cystic fibrosis?

Treatment options for people with adult onset CF include antibiotics to manage and prevent infections and physical therapy to clear the airway and protect lung function. Supplements to help your stay nourished and lifestyle changes, such as avoiding cigarette smoke and chemical exposure, may also be recommended.

CF can be diagnosed in people as adults. The treatment strategy for a CF diagnosis later in life will be similar to a CF diagnosis in childhood.