Introduction
Cystic fibrosis (CF) is an inherited genetic disorder that makes mucus, sweat, and digestive juices abnormally thick and sticky. Thick mucus blocks airways and pancreatic ducts, leading to breathing problems, recurrent infections, and poor nutrient absorption.
CF is caused by disease-causing variants in both copies of the CFTR gene (autosomal recessive). It is more common in some populations of northern European ancestry, but occurs worldwide. Newborn screening helps earlier diagnosis where available.
There is no permanent cure yet, but modern care—airway clearance, antibiotics, pancreatic enzymes, nutrition support, and CFTR modulators for eligible mutations—has greatly improved survival and quality of life.
This page is educational and not a substitute for care at a specialised CF centre. Suspected or confirmed CF needs multidisciplinary follow-up.
Overview
In healthy people, mucus is thin and slippery. In CF it becomes glue-like, trapping bacteria in the lungs and blocking digestive enzymes from reaching the intestine. Sweat also contains excess salt.
Symptoms may appear in infancy (meconium ileus, failure to thrive, recurrent pneumonia) or, in milder atypical forms, later in adolescence or adulthood. Most men with classic CF have infertility due to absent or blocked vas deferens; women may have reduced fertility.
Lifelong care focuses on clearing airways, treating infections, replacing enzymes and calories, vaccinations, and mutation-specific CFTR modulators when available. Advanced lung or liver disease may lead to transplant evaluation.
- CFTR gene mutations → thick mucus and salty sweat
- Main organs: lungs, pancreas, intestines, sinuses, reproductive tract
- Autosomal recessive—both parents usually carriers
- Symptoms: chronic cough, infections, malabsorption, salty skin
- Diagnosis: newborn IRT screen, sweat chloride test, genetic testing
- Treatment: airway care, antibiotics, enzymes, CFTR modulators
- Not contagious—genetic condition
- No cure yet; early specialised care improves outcomes
What happens in the body
CFTR protein regulates salt and water movement across cell membranes. Faulty CFTR dries secretions, so mucus thickens and plugs ducts. In lungs this drives infection–inflammation cycles and progressive damage (bronchiectasis, fibrosis, cyst-like changes).
In the pancreas, enzyme blockage causes fat malabsorption and vitamin deficiencies. Sweat glands fail to reabsorb salt normally, which is why the sweat chloride test is diagnostic.
- Defective CFTR → disrupted salt–water balance
- Thick mucus blocks airways and pancreatic ducts
- Trapped bacteria → chronic lung infection
- Missing enzymes → malnutrition
- Excess salt in sweat
- Mutation class affects severity and drug eligibility
Signs and symptoms
Symptoms vary by age and organ involvement. Common patterns include:
- Persistent cough with thick sputum
- Wheezing or breathlessness
- Repeated lung or sinus infections
- Easy fatigue with exercise
- Nasal congestion, sinusitis, or nasal polyps
- Greasy, foul-smelling stools
- Poor weight gain despite good appetite
- Constipation or intestinal blockage
- Meconium ileus in newborns
- Salty-tasting skin or sweat
- Pancreatitis or CF-related diabetes symptoms
- Male infertility; fertility challenges in some women
- Finger clubbing with long-standing lung disease
- Acute exacerbations with fever, more sputum, and worse breathing
Causes and risk factors
CF is genetic. Key points about inheritance and risk:
- Pathogenic CFTR mutations on both alleles
- Autosomal recessive inheritance—25% risk per pregnancy if both parents are carriers
- Family history of CF or unexplained childhood lung/digestive disease
- Carrier parents usually have no symptoms themselves
- Higher carrier rates in some ancestral groups
- Lifestyle does not “create” CF, but smoke and infections worsen lung disease
- Not spread by food or contact—not infectious
- De novo mutations are rare; most cases are inherited
- Prenatal and carrier testing can clarify family risk
- Mutation class influences clinical severity
Diagnosis and evaluation
Confirmation combines screening, sweat testing, and genetics:
- Newborn screening with immunoreactive trypsinogen (IRT), then follow-up
- Sweat chloride test—elevated salt strongly supports CF
- CFTR genetic testing to identify mutations and guide family screening
- Chest imaging and lung function tests to assess severity
- Stool/enzyme assessment for pancreatic insufficiency
- Sputum cultures to track pathogens such as Pseudomonas
- Consider CF in older patients with chronic respiratory/digestive disease or infertility
- Carrier/prenatal testing for family planning
- Monitor liver function and glucose for complications
Treatment and management
Care is lifelong and multidisciplinary. Goals include fewer infections, clearer airways, and good nutrition:
- Daily airway clearance—chest physiotherapy, oscillating devices, cough techniques
- Mucolytics, bronchodilators, and inhaled antibiotics when indicated
- Systemic antibiotics for exacerbations and chronic infection
- Pancreatic enzymes with meals plus fat-soluble vitamins
- High-calorie nutrition; extra salt and fluids in heat or exercise
- Mutation-eligible CFTR modulators (ivacaftor-based combinations where available)
- Pulmonary rehab, oxygen, sinus surgery, or feeding tubes when needed
- Lung (or liver) transplant evaluation for end-stage disease
- Separate management of CF-related diabetes and liver disease
- Routine immunisations including annual influenza vaccine
Prevention, self-care, and lifestyle
Not every condition is fully preventable, but the steps below may lower risk or recurrence:
- CF itself is not preventable once mutations are inherited; carrier testing informs reproductive choices
- For diagnosed patients, treatment adherence is the main way to prevent complications
- Avoid smoking and second-hand smoke completely
- Hand hygiene and limiting contact with sick people, especially in flu season
- Regular CF clinic follow-up (often about every 3 months) and lung function monitoring
- Nutrition and enzyme routines to prevent malnutrition
- Mental-health support for the burden of chronic disease
Possible complications
Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:
- Bronchiectasis and chronic lung infections (e.g., Pseudomonas)
- Hemoptysis (coughing blood) or pneumothorax
- Respiratory failure
- Malnutrition and vitamin deficiencies
- DIOS/intestinal obstruction; liver disease
- CF-related diabetes
- Infertility and anxiety or depression
When to see a doctor or seek emergency care
Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:
- Child with chronic cough, recurrent pneumonia, or poor weight gain
- Newborn with delayed meconium passage or bowel obstruction signs
- Known CF with sudden worsening—fever, more breathlessness
- Coughing up blood or severe chest pain
- Severe abdominal pain or vomiting suggesting bowel blockage
- Family history of CF when planning pregnancy—seek genetic counselling
- Do not skip scheduled multidisciplinary follow-up
Living with the condition
Daily airway clearance and medicines are the foundation of lung protection—build them into school and work schedules.
Work with a dietitian on high-calorie intake and enzymes; increase salt and fluids in hot weather. Regular exercise helps loosen mucus.
Stay connected with the CF care team; mental health and reproductive planning are part of comprehensive care.
Frequently asked questions
Is cystic fibrosis contagious?
No. It is a genetic condition and cannot be caught from another person.
Can CF be cured?
There is no permanent cure yet, but modern treatments help many people live longer, more active lives.
What are early signs in babies?
Salty skin, poor weight gain, greasy stools, recurrent lung infections, or meconium ileus.
Can people with CF have children?
Most men need assisted reproduction. Many women can conceive with medical support and careful pregnancy planning.
How often are clinic visits needed?
Typically at least every three months, and sooner if symptoms worsen.
Is exercise safe?
Yes—when cleared by the care team. Activity helps lung function and mucus clearance.
Important caution
This article is general health education in English. It is not personal medical advice or a prescription.
Cystic fibrosis is a lifelong condition that responds best to regular specialised, multidisciplinary care.
Seek emergency care for severe breathlessness or coughing up blood.