Tuberculosis (TB): Causes, Symptoms, Treatment

Medically Reviewed by Poonam Sachdev on July 27, 2023
8 min read

Tuberculosis (TB) is a contagious infection that usually attacks your lungs. It can also spread to other parts of your body, like your brain and spine. A type of bacteria called Mycobacterium tuberculosis causes it.

This bacteria is thought to be over 3 million years old. Knowledge of the disease dates back to ancient Greece and Rome. Tuberculosis, formerly called consumption, was the top cause of death in the U.S. at the beginning of the 20th century.

While it's largely controlled in the U.S. now, it still kills more than a million people worldwide every year.

People with HIV/AIDS and others with weakened immune systems are at higher risk of getting tuberculosis because their bodies have a harder time fighting the bacteria.

A TB infection doesn’t always mean you’ll get sick. There are several stages and forms of the disease:

  • Primary TB. This is the first stage of a tuberculosis infection. Your immune system may be able to fight off the germs. But sometimes it doesn't destroy all of them, and they keep multiplying. You may not have any TB symptoms at this stage, or you might have a few flu-like symptoms.
  • Latent TB. You have the germs in your body, but your immune system keeps them from spreading. You don’t have any symptoms, and you’re not contagious. But the infection is still alive and can one day become active. If you’re at high risk for reactivation, your doctor will give you medications to prevent active TB. This usually happens if you have HIV, you had an infection in the past 2 years, your chest X-ray is unusual, or your immune system is weakened.
  • Active TB. The germs multiply and make you sick. You can spread the disease to others. Some 90% of active cases in adults come from a latent TB infection.
  • Active TB outside the lungs. A tuberculosis infection that spreads from your lungs to other parts of the body is known as extrapulmonary tuberculosis. Your symptoms will depend on which part of your body the infection affects.

A latent or active TB infection can also be drug-resistant, meaning certain medications don’t work against the bacteria.

Latent TB doesn’t have symptoms. A skin or blood test can tell if you have it.

Active tuberculosis symptoms in the lungs include:

  • A cough that lasts more than 3 weeks
  • Chest pain
  • Coughing up blood
  • Feeling tired all the time
  • Night sweats
  • Chills
  • Fever
  • Loss of appetite
  • Weight loss

When TB is outside the lungs, you may have these same symptoms along with pain near the area that's infected.

TB symptoms may look different in teens, children, and babies. Teens' symptoms are similar to those of adults. Children ages 1-12 may have weight loss and a fever that won't go away.

Babies may:

  • Be inactive or move slowly
  • Have a bulge in the soft spot on their head
  • Be very fussy
  • Throw up or have trouble feeding

If you or your child have any of these symptoms, see a doctor to get tested. Get medical help right away if you have chest pain.

Tuberculosis bacteria spread through the air, just like a cold or the flu. You can get TB only if you come into contact with people who have it.

When someone who has TB coughs, sneezes, talks, laughs, or sings, they release tiny droplets that contain the germs. If you breathe in these germs, you can get the disease. This is why people who have active tuberculosis in their lungs or throat are more likely to infect others. You usually can't spread TB if you have it in other areas of your body. 

TB is not easy to catch. You’re most likely to get it from co-workers, friends, or family members with whom you spend lots of time indoors.

Tuberculosis germs don’t thrive on surfaces. You can’t get it from:

  • Shaking hands 
  • Kissing
  • Sharing food or drink
  • Sharing bed sheets, towels, or toothbrushes
  • Toilet seats 

You're more likely to get tuberculosis if:

  • A friend, co-worker, or family member has active TB.
  • You live in or have traveled to an area where TB is common, like Russia, Africa, Eastern Europe, Asia, Latin America, and the Caribbean.
  • You’re part of a group in which TB is more likely to spread, or you work or live with someone who is. This includes people who are unhoused, people with HIV, those in jail or prison, and those who inject drugs.
  • You work or live in a hospital or nursing home.
  • You’re a health care worker for patients at high risk of TB.
  • You’re a smoker.

You're at higher risk of developing active TB if you have: 

  • HIV or AIDS
  • Diabetes
  • Serious kidney disease
  • Head or neck cancer
  • Low body weight and poor nutrition

Or use:

  • Cancer treatments such as chemotherapy
  • Medications for organ transplants
  • Certain drugs to treat rheumatoid arthritis, Crohn’s disease, and psoriasis

Babies and young children are at higher risk for developing active TB because their immune systems aren’t fully formed. Children under 5, teens and young adults ages 15-25, and adults 65 and older are most likely to get active tuberculosis.

How serious is tuberculosis?

Tuberculosis can be fatal if you don't treat it. Over 1.5 million people worldwide died from tuberculosis in 2021. It's the second most deadly infectious disease (after COVID-19) and the 13th leading cause of death in the world.

But TB is treatable. The World Health Organization estimates that TB treatment saved 74 million lives between 2000 and 2021. 

To look for tuberculosis, your doctor may start with a physical exam that includes listening to your lungs and looking for swollen lymph nodes

If they think you might have it, they can order TB tests.

Tuberculosis testing

There are two common tests for tuberculosis:

  • Tuberculosis skin testing. This is also known as the Mantoux tuberculin skin test. A technician injects a small amount of fluid into the skin of your lower arm. After 2-3 days, they’ll check for swelling in your arm. You might get this test more than once.
  • Tuberculosis blood testing. These tests, also called interferon-gamma release assays (IGRAs), measure the response when TB proteins are mixed with a small amount of your blood.

Tuberculosis test results

If your skin test results are positive, you most likely have TB bacteria. But you could also get a false positive. If you’ve gotten a tuberculosis vaccine called Bacillus Calmette-Guerin (BCG), the test could say you have TB when you really don’t. You can also get a false negative, saying that you don’t have TB when you really do, if your infection is very new.

Skin and blood tests can't show whether your infection is latent or active. To figure that out, your doctor can do:

  • A chest X-ray or CT scan to look for changes in your lungs
  • Acid-fast bacillus (AFB) tests for TB bacteria in your sputum, the mucus that comes up when you cough

Is there a cure for tuberculosis?

Most cases are cured with antibiotics. But it takes a long time. You have to take medications for at least 6 to 9 months.

How is tuberculosis treated?

Your treatment will depend on your infection.

  • If you have latent TB, your doctor will give you medication to kill the bacteria so the infection doesn’t become active. You might get isoniazid, rifampin, or rifapentine either alone or combined. You’ll have to take the drugs for 3 months or more. If you see any signs of active TB, call your doctor right away.
  • A combination of medicines also treats active TB. The most common are ethambutol, isoniazid, pyrazinamide, and rifampin. You’ll take them for 6 to 12 months.
  • If you have drug-resistant TB, your doctor might give you one or more different medicines. You may have to take them for much longer, up to 30 months, and they can cause more side effects.

Drug-resistant TB

Some strains of TB are resistant to antibiotics. Bacteria become drug-resistant because of changes to their genetic makeup. That can happen randomly. But when antibiotics are overprescribed or used incorrectly, this speeds up the process.

Whatever kind of infection you have, it’s important to finish taking all of your medications, even when you start feeling better. If you quit too soon, the medication might not wipe out all the TB bacteria in your body. Finishing your treatment also helps prevent new strains of drug-resistant bacteria.




Like any medication, TB drugs can have side effects. Common isoniazid side effects include:

  • Numbness and tingling in your hands and feet
  • Upset stomach, nausea, and vomiting
  • Loss of appetite
  • Weakness

Ethambutol side effects include:

  • Chills
  • Painful or swollen joints
  • Belly pain, nausea, and vomiting
  • Loss of appetite
  • Headache
  • Confusion
  • Eye issues such as pain and vision problems

Some pyrazinamide side effects include:

  • Lack of energy
  • Nausea and vomiting
  • Loss of appetite
  • Muscle or joint pain

Common rifampin side effects include:

  • Skin rash
  • Upset stomach, nausea, and vomiting
  • Brown urine
  • Yellowish skin or eyes (jaundice)
  • Diarrhea
  • Loss of appetite
  • Inflamed pancreas

Tuberculosis infection can cause complications such as:

  • Joint damage
  • Lung damage
  • Infection or damage of your bones, spinal cord, brain, or lymph nodes
  • Liver or kidney problems
  • Inflammation of the tissues around your heart

To help stop the spread of TB:

  • If you’re traveling to a place where TB is common, avoid spending a lot of time in crowded places with sick people. 
  • If you have a latent infection, take all your medication so it doesn’t become active and contagious.

If you have active TB, you'll need to take care to protect others from infection during your first few weeks of treatment:

  • Limit contact with other people. If you live with others, sleep in a separate room and isolate yourself as much as possible. 
  • Cover your mouth when you laugh, sneeze, or cough. 
  • Wear a surgical mask when you’re around other people.
  • Keep your space ventilated. Open windows, if possible, and use a fan. Germs spread more easily in poorly ventilated places. 

Tuberculosis vaccine

Children in countries where TB is common often get the BCG vaccine. It isn’t widely used in the U.S., and it doesn’t always protect against infection. Doctors recommend it only for children living with someone who has an active TB infection with a very drug-resistant strain or who can’t take antibiotics.

Your outlook depends on several things, including your overall health, how serious the infection is, and how well you follow your doctor’s directions on treatment. In the United States, experts estimate that treatment works in more than 95% of cases.

Tuberculosis (TB) is an age-old disease that still kills millions of people worldwide each year. But It's treatable and preventable. If you think you might have TB, see your doctor right away. If you've been diagnosed with TB, take steps to protect others and make sure you complete your treatment.

How serious is tuberculosis?

Most people with the tuberculosis bacteria don't get sick. But active tuberculosis can be very serious, even fatal, if it goes untreated. It could permanently damage your lungs. If it spreads to other parts of your body,  it can cause short- or long-term complications there.  

Does tuberculosis ever go away?

Across the world, nearly 9 out of 10 cases of TB and almost half of cases of drug-resistant TB are eventually cured. While treatment can last several months, you might start feeling better in a few weeks. 

How contagious is tuberculosis?

TB is contagious in its active stage. But you usually need to have lots of contact with an infected person to get it. It spreads only through droplets in the air that you breathe in. Most people who are exposed to TB are able to fight off the bacteria and keep it from becoming active.  

Does anyone still get tuberculosis?

In 2021, more than 10.5 million people were infected with the disease. Parts of the world with the most TB cases include Southeast Asia, Africa, and the Western Pacific.