Types of Haemophilus influenzae Infections

Haemophilus influenzae, a type of bacteria, can cause many different kinds of infections. These infections range from mild, like ear infections, to serious, like bloodstream infections.

Doctors consider some H. influenzae infections “invasive.” Invasive disease happens when the bacteria invade parts of the body that are normally free from germs. For example, H. influenzae can invade the fluid around the spine and brain, causing meningitis, or bloodstream, causing bacteremia. Invasive disease is usually serious, requiring treatment in a hospital, and can sometimes result in death.

The most common types of invasive disease caused by H. influenzae are:

  • Pneumonia* (lung infection)
  • Bloodstream infection
  • Meningitis (swelling of the lining of the brain and spinal cord)
  • Epiglotittis (swelling in the throat)
  • Cellulitis (skin infection)
  • Infectious arthritis (inflammation of the joint)

H. influenzae can also be a common cause of ear infections in children and bronchitis in adults. Learn more about these illnesses.

*Doctors consider pneumonia an invasive infection when H. influenzae also infect the blood or fluid surrounding the lungs.