Symptoms of cystic fibrosis are usually caused by the production of thick, sticky mucus. Symptoms vary from person to person and are not always obvious in childhood.

Early signs and symptoms

Symptoms of cystic fibrosis in a baby or young child may include:

• A blocked small intestine at birth, called a meconium plug or meconium ileus.
• Salty sweat or skin.
• Not wanting to eat, having little energy, or losing weight. This is sometimes called failure to thrive.
• Unusual bowel movements. This may include diarrhea that does not go away; large, greasy stools; very smelly stools; or constipation. If the intestines become blocked, the child's belly may stick out and the child may not be able to have a bowel movement.
• Breathing problems or getting tired easily while playing.
• A cough that does not go away or wheezing.

Later signs and symptoms

Over time, symptoms may get worse and result in:

• Coughing up mucus that sometimes has blood in it.
• Difficulty exercising or not being able to exercise.
• Rectal prolapse, when part of the rectum protrudes from the anus.

Additional symptoms may develop during late childhood or early adulthood, including:

• Clubbing (rounding and flattening) of the fingers.
• Growths (polyps) in the nose or sinuses.
• Not being able to have children (infertility).