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Frequent Infections

Reviewed by: HU Medical Review Board | Last reviewed: March 2024 | Last updated: March 2024

People with type 2 diabetes (T2D) have a higher risk of infections. T2D also increases the risk of infections becoming severe. High blood sugar levels weaken our immune system. This makes it harder to fight off germs.1,2

Getting sick can make it harder to manage blood sugar levels. Your blood sugar levels may increase as your body fights off an infection. Talk to your doctor if you notice symptoms of an infection. They can discuss treating the infection and controlling your blood sugar levels.1,2

What infections are common for people with T2D?

Knowing what infections are common can lead to early diagnosis and treatment. This can help prevent infections from becoming more serious. It can also reduce long-term complications. The most common infections in people with T2D affect the:2-4

  • Skin
  • Soft tissues
  • Urinary tract
  • Respiratory tract

Foot infections

Foot complications are common in T2D. Infections, ulcers, and other foot issues are leading causes of hospitalization. Foot problems in people with T2D are usually caused by nerve damage (neuropathy). Neuropathy can lead to:5

  • Loss of feeling, so you might not notice a foot injury
  • Decreased ability to control sweat and oil, which can lead to dry and cracked skin that bacteria can enter
  • Foot deformities, which can lead to soft tissue damage

T2D can also impair blood flow to the feet. This makes it harder for the immune system to fight infections and heal ulcers. People with T2D should routinely check their feet. Cuts or wounds can heal slowly and lead to serious infections. If untreated, foot infections can require amputation or lead to death.5

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Urinary tract infections

T2D increases your risk for urinary tract infections and is the major risk factor for certain rare but serious types of urinary tract infections (UTIs). These emphysematous UTIs are linked to gas formation. They can involve the bladder, pelvis, and kidney.6,7

Prolonged high blood sugar increases sugar excreted in the urine, which can promote the growth of gas-forming bacteria. People with T2D may have a reduced ability to empty their bladder, which can increase the risk of UTIs. If the bladder does not empty, harmful bacteria can stay in the urinary tract longer and have the opportunity to grow and cause an infection.7

Most UTIs occur in the bladder. But they can turn into kidney infections if not treated quickly. Kidney infections can make it harder to control T2D. They can increase insulin resistance and make it harder to stay hydrated. Signs of UTIs include:3,7

  • Increased or strong urge to urinate
  • Pain or burning feeling when urinating
  • Urine that looks cloudy or has blood in it
  • Strong-smelling urine
  • Nausea or vomiting
  • Fever or chills
  • Pain in your back, side, or groin

Skin and soft tissue infections

T2D increases the risk of bacterial and fungal infections that affect skin and soft tissue. These infections can affect any skin surface but most often involve the feet.3,8

People with T2D may have an increased risk of bacterial skin infections, including:6,8

  • Cellulitis – infection of the skin and underlying tissue
  • Necrotizing fasciitis – infection of tissue under the skin that causes death of that tissue (“flesh-eating”)
  • Fournier gangrene – a relatively rare form of necrotizing fasciitis affecting the genitals or perineum (area between the anus and genitals)
  • Erythrasma – skin infection that most commonly involves toe webs, armpit, and groin areas, causing red-brown patches or plaques
  • Folliculitis – infections of the hair follicles
  • Styes – infections of the glands of the eyelids at the base of the eyelashes

The most common fungal infections in people with T2D include:6,8,9

  • Tinea pedis – athlete’s foot
  • Onychomycosis – fingernail and toenail infections
  • Candidiasis – yeast infections
  • Thrush – candidiasis of the mouth and/or throat

Respiratory infections

T2D increases the risk of severe respiratory infections, including pneumonia. People with T2D have higher rates of hospitalization and death from pneumonia.6

Symptoms of respiratory infections vary. Possible symptoms include:6

  • Body aches
  • Cough, which may produce discolored or bloody mucus
  • Fatigue
  • Fever, chills
  • Shortness of breath

Ear, nose, and throat infections

Some infections are seen mostly in people with T2D. They tend to be more common when diabetes is uncontrolled. These include:3,6,10-12

  • Malignant (necrotizing) otitis externa – a bacterial infection that starts in the ear and causes severe ear pain and drainage and causes tissue death (“flesh-eating”)
  • Rhinocerebral mucormycosis – a fungal infection that starts in the sinuses and can spread to the brain

These are rare but serious infections. They can cause life-threatening complications if not treated quickly.11,12

Why does T2D cause infections?

Your immune system helps fight off germs. Certain immune cells called white blood cells circulate throughout your body. They trigger your immune system to fight off things that can make you sick (pathogens) like:1,13

  • Bacteria
  • Viruses
  • Fungi

High blood sugar makes white blood cells work harder. This means your immune system may be weaker. It may have more difficulty fighting off infections. This increases the risk of frequent and severe illnesses. It also makes it harder to recover from illnesses.1,13

How are infections prevented and treated?

The first step to preventing infections is to keep your blood glucose under control. Other ways to lower your risk of infections include:1

  • Taking medicines as prescribed by your doctor
  • Getting enough sleep, exercise, and fruits and vegetables
  • Practicing good hygiene by washing your hands often
  • Getting a flu shot each year and talking to your doctor about pneumococcal and other vaccines
  • Examining your feet and skin every day

Talk to your doctor if you notice any signs of an infection. Treatment varies but often involves antibiotic or antimicrobial drugs. Certain medicines for infection have side effects that may affect T2D management.6,8