Diabetes can affect the body's immune system, impairing the ability of white blood cells to come to the site of an infection, stay in the infected area, and kill microorganisms. Because of the buildup of plaque in blood vessels associated with diabetes, areas of infection may receive a poor blood supply, further decreasing the body's ability to fight infections and heal wounds.

Common infections

People with diabetes can be more severely affected by common infections, such as pneumonia caused by Streptococcus pneumoniae. In addition, people with diabetes are more likely to be infected with unusual organisms, such as Gram-negative bacteria or fungi, and can also be infected with a mixed group of organisms because of their poor healing capacity and impaired immune system.

Foot infections

Foot infections are common in people with diabetes. Nerve damage (neuropathy) combined with poor blood supply to the feet puts people with diabetes at high risk for developing infected foot ulcers.

Other infections

Other infections for which people with diabetes are at increased risk include:

• Yeast infections on the skin and in the urinary tract.
• Severe infection of the outer ear with the bacteria Pseudomonas aeruginosa called malignant otitis externa.
• Extremely serious infection of the nose and sinuses with the fungus mucor.