Signs of Infection in Dementia and Alzheimer's

If you have a loved one with Alzheimer's disease or another kind of dementia such as vascular, Lewy body, or frontotemporal, it's important to be on the lookout for infections. Typically, a person whose cognitive functioning is intact would tell us of some pain they're experiencing or express that they don't feel well, but dementia makes this process more difficult because the person can't always find the words to express a feeling or concern. So, how can you tell if your loved one may have an infection?

A woman checking her husbands temperature
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Symptoms of an Infection in Dementia

A person with dementia who is experiencing an infection may demonstrate the following symptoms:


You might not be able to rely on the person to be able to fully verbalize feeling hot, but you should pay attention to an extra warm forehead, dry lips or skin, or signs of shivering.

Increased Confusion

Although it may sound like a challenge to notice confusion in someone who already has dementia, an infection often can cause significant changes that may include increased disorientation to those around him, his location and the time, as well as poor judgment.

Pain or Discomfort

Watch for non-verbal signs of pain such as grimacing, guarding against touch, crying, refusing to eat and restlessness. 

Urinary Tract Infection Symptoms

Check your loved one's urine for increased odor, cloudiness, dark color or blood in urine.

Increased Lethargy

An out-of-the-ordinary fatigue, apathy and desire to sleep can indicate infection.

Decreased Appetite

Some infections can cause nausea and vomiting, and others might just cause someone to feel a little "off" to the point where they just don't want to eat. 


Infections can affect balance and cause muscle weakness. If your loved one has a fall, be sure to consider if they might have an infection.

Paranoia, Delusions, or Hallucinations

Seeing or hearing things that aren't there could be indicative of an infection, especially if your loved one does not normally experience hallucinations. Some people become very suspicious of others when they have an infection.

Behavior Changes

Many people with Alzheimer's and other kinds of dementia experience challenging behaviors, but an infection can cause a significant increase in the frequency and intensity of such behaviors. For example, your loved one might regularly be somewhat resistive to getting dressed in the morning, but an infection could trigger a catastrophic reaction where they are screaming, swearing, hitting and throwing things. As with other symptoms, the key to detecting an infection is that the behavior or other symptom is worse than normal or changed from what is normal.


An infection, among other conditions, can trigger delirium (confusion and disorientation). Knowing the difference between delirium and dementia can help you consider if your loved one is possibly in need of treatment for an infection.

Types of Infections

There are many types of infections, but the most common types are an upper respiratory infection (such as pneumonia) and urinary tract infections. Others may include infections of the sinuses, ears, skin, and teeth.

What to Do If You Think Your Loved One Has an Infection

Advocate for him. Inform the doctor, and begin by explaining what his normal behavior, mood, and cognitive functioning are. Be sure to explain any changes to the physician, as well as if he has a history of frequent urinary tract infections, for example.

If an antibiotic is prescribed, be sure to administer the whole course that is prescribed, even if your loved one appears to be feeling better. Sometimes, doctors might recommend additional treatments, such as an inhaler or nebulizer for an upper respiratory infection. If your loved one is resistive to whatever kind of treatment that is prescribed, notify the physician again so that an alternative treatment can be considered.

Preventing Infections 

  • Wash hands and use hand sanitizer
  • Avoid the use of a catheter if at all possible
  • Get an annual flu shot for both you and your loved one
  • Practice good hygiene if assisting with incontinence
  • Encourage adequate hydration

A Word From Verywell

Because you know your loved one well, you're uniquely positioned to notice any changes in him. Your vigilance in detecting these signs of infection and communicating them to the physician plays a significant role in his well-being and quality of life. 

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. D'Agata E, Loeb MB, Mitchell SL. Challenges in assessing nursing home residents with advanced dementia for suspected urinary tract infectionsJ Am Geriatr Soc. 61(1):62–66. doi:10.1111/jgs.12070

  2. Mitchell SL. Care of patients with advanced dementia. UpToDate.

  3. National Institute of Diabetes Digestive and Kidney Diseases. Eating, diet, and nutrition.

By Esther Heerema, MSW
Esther Heerema, MSW, shares practical tips gained from working with hundreds of people whose lives are touched by Alzheimer's disease and other kinds of dementia.