7 Diseases That Can Be Asymptomatic

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Uncomfortable symptoms are usually the first clue that something is wrong with your body. Sniffles, sinus pressure, and a scratchy throat are often the initial signs of a cold, and pain, redness, and a fever can signal infection in just about any part of the body.

Some illnesses, though, don’t have any obvious symptoms, especially in the early stages of disease. Unfortunately, some of these diseases can cause serious harm to the body before they are detected.

These seven diseases are often asymptomatic, but can be detected via regular medical checkups, giving you the opportunity to pursue health-preserving treatment.


Hypertension, or high blood pressure, has been called a “silent killer” because it can be a deadly, symptom-less condition.

Think about it: you usually don’t know the pressure inside a hose is too high until the hose springs a leak or explodes. You do not want that to happen to one of your blood vessels. That’s why regular medical appointments and blood pressure checks are so important. Blood pressure readings can reveal high blood pressure so you can take action to protect your health.

According to the American Heart Association, nearly half of the American population over age 20 has high blood pressure, and many don’t know it.

High cholesterol 

High cholesterol increases your chances of developing heart disease, heart attack, or stroke. You can’t feel high cholesterol, though, so doctors use blood tests to check patients’ cholesterol levels. Treatment, including lifestyle and dietary changes and medication, can decrease high cholesterol levels.

The American Heart Association recommends cholesterol testing every 4 to 6 years for adults ages 20 and older who are at low risk of developing heart disease. People at high risk (due to family or personal medical history) may need their cholesterol checked more often.


Hepatitis, an infection or inflammation of the liver can be acute (short-lived) or chronic. Acute infections usually don’t cause symptoms and go away without treatment. Some asymptomatic acute infections, though, turn into chronic hepatitis, which can cause liver cirrhosis and liver failure. And some people with acute Hepatitis A may become symptomatic feeling very sick, fatigued and jaundiced.

Hepatitis B and C, the two types of hepatitis that are most likely to cause long-term health problems, are caused by viruses that are spread via contact with blood and body fluids. A history of blood transfusions, injectable drug use, or healthcare work may increase your risk of hepatitis.

If you are at risk for hepatitis infection, your healthcare provider can order blood tests to check for hepatitis. Treatment can decrease the risk of long-term complications and, in many cases, even cure the underlying infection.


More than 7 million adults in the United States likely have diabetes but don’t know it, according to the U.S. Centers for Disease Control. Although diabetes can cause frequent and intense hunger, thirst, and urination, these classic symptoms are usually not apparent in the early stages of disease. Unfortunately, high blood sugar levels can damage the kidneys, eyes and blood vessels.

Doctors can detect diabetes by checking blood sugar levels, and prompt diagnosis and treatment may help individuals avoid or delay organ damage.


Although many people picture sores or ulcers when they think about herpes, the truth is most herpes infections are asymptomatic. The classic genital herpes lesions may be apparent during breakouts—or may be so mild that they go unnoticed. Between breakouts, there are no visible symptoms of infection.

Practicing safer sex, including the use of male condoms and dental dams, may prevent transmission of genital herpes.


Glaucoma is a leading cause of irreversible blindness, but it typically doesn’t cause symptoms until the condition is quite advanced. Changes in vision can be a symptom of glaucoma, but because the changes occur gradually—and often after age 60—many people attribute their worsening vision to aging.

Regular eye exams allow doctors to detect and treat glaucoma. Treatment can slow progression of the disease and prevent vision loss. The American Academy of Ophthalmology recommends comprehensive eye exams every 5 to 10 years for individuals younger than age 40; every 2 to 4 years for people ages 40 to 54; every 1 to 3 years for people 55 to 64; and every 1 to 2 years for people over age 65.


Cough, fever, fatigue and loss of taste or smell are classic symptoms of COVID-19. But you could have the disease—and spread it to others—even if you feel fine.

According to research conducted through April 2021, approximately one-third of people with COVID-19 have no symptoms. Asymptomatic disease is more common in children and may be more common in people who have been vaccinated.

If you have been exposed to COVID-19, ask your healthcare provider if you should quarantine and undergo testing.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Sep 3
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. What are the Symptoms of High Blood Pressure? American Heart Association. https://www.heart.org/en/health-topics/high-blood-pressure/why-high-blood-pressure-is-a-silent-killer/what-are-the-symptoms-of-high-blood-pressure
  2. Why High Blood Pressure is a “Silent Killer.” American Heart Association. https://www.heart.org/en/health-topics/high-blood-pressure/why-high-blood-pressure-is-a-silent-killer
  3. What is High Blood Pressure? American Heart Association. https://www.heart.org/-/media/files/health-topics/answers-by-heart/what-is-high-blood-pressure.pdf?la=en
  4. How to Get Your Cholesterol Tested. American Heart Association. https://www.heart.org/en/health-topics/cholesterol/how-to-get-your-cholesterol-tested
  5. High Cholesterol Facts. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/cholesterol/facts.htm
  6. Hepatitis C. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/hepatitis-c
  7. Viral Hepatitis B. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/hepatitis/viral-hepatitis-b
  8. Prevalence of Both Diagnosed and Undiagnosed Diabetes. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/diabetes/data/statistics-report/diagnosed-undiagnosed-diabetes.html
  9. Diabetes Symptoms. American Diabetes Association. https://www.diabetes.org/diabetes/type-1/symptoms
  10. Genital Herpes. U.S. Centers for Disease Control and Prevention.https://www.cdc.gov/std/herpes/stdfact-herpes-detailed.htm
  11. Herpes Simplex Virus. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus
  12. What are Common Glaucoma Symptoms. American Academy of Ophthalmology. https://www.aao.org/eye-health/diseases/glaucoma-symptoms
  13. Glaucoma. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/glaucoma/symptoms-causes/syc-20372839
  14. What the Data Say About Asymptomatic COVID Infections. Nature. https://www.nature.com/articles/d41586-020-03141-3
  15. Sah, P., Fitzpatrick, M., Zimmer, C., Abdollahi, E., Juden-Kelly, L., & Moghadas, S. et al. (2021). Asymptomatic SARS-CoV-2 infection: A systematic review and meta-analysis. Proceedings Of The National Academy Of Sciences, 118(34), e2109229118. doi: 10.1073/pnas.2109229118. Retrieved from https://www.pnas.org/content/118/34/e2109229118