Cysts are usually caused by blockages, fluid buildup, or inflammation in a gland, duct, hair follicle, or tissue pocket. They can also be linked to infections, injury, hormone changes, genetics, tumors, or certain medical conditions such as polycystic ovary syndrome or polycystic kidney disease.

Common causes

  • Blocked glands or ducts.
  • Trapped fluid, keratin, or other material.
  • Skin irritation or injury.
  • Infection.
  • Hormonal changes.
  • Genetic or inherited conditions.

Important note

Many cysts are benign and cause no symptoms, but some can become painful, infected, or enlarge enough to press on nearby tissue.

When to get checked

A new lump or swelling should be examined by a clinician, especially if it is painful, growing, red, warm, or comes with fever.

Quick scoop

Most cysts happen because the body’s normal drainage or tissue-building process gets interrupted, but the exact cause depends on the type and location of the cyst.