Symptoms of cystic fibrosis vary from patient to patient. Many patients with mild forms of this illness do not experience symptoms until they reach adolescence or young adulthood. Once symptoms appear, they are usually related to the thick, sticky mucus that is characteristic of the disease. Even if symptoms are initially mild, they usually get steadily worse over time.

Additional symptoms most often involve lung and digestive problems. They may include:

• Chronic coughing, including expulsion of thick mucus
  
  
• Regular episodes of bronchitis and pneumonia that may cause inflammation and permanent lung damage
  
  
• Salty-tasting skin
  
  
• Dehydration
  
  
• Infertility (mostly in men)
  
  
• Chronic diarrhea or bulky, light-colored, foul-smelling, greasy stool
  
  
• Big appetite, but inability to gain weight (failure to thrive)
  
  
• Fatigue
  
  
• Frequent sinus infections
  
  
• Intestinal blockage in newborns
  
  
• Stomach pain and discomfort resulting from too much gas in the stomach
  
  
• Persistent wheezing
  
  
• Poor height growth