What tuberculosis symptoms look like

Tuberculosis (TB) causes a persistent cough that lasts three weeks or longer. The cough often brings up sputum—the mucus and phlegm you cough up—and sometimes blood. You may also run a fever, especially in the afternoon or evening, and wake up drenched in sweat at night. Many people with TB feel tired, lose weight without trying, and lose their appetite.

These symptoms develop slowly over weeks or months, not suddenly like flu. That gradual onset is one reason TB can go undiagnosed for a while—people often assume they have a lingering cold or bronchitis. The cough is the hallmark sign, but not everyone with TB coughs. The location of the infection in your body determines which symptoms appear.

Key Takeaways

  • A cough lasting longer than three weeks, especially one that produces sputum or blood, is the most common sign of TB and warrants a doctor's visit.
  • Fever, night sweats, weight loss, and fatigue often accompany the cough and develop gradually over weeks rather than appearing suddenly.
  • TB in the lungs (pulmonary TB) causes respiratory symptoms, while TB in other parts of the body produces different signs depending on the location.
  • You can carry TB bacteria without symptoms for years; a skin test or blood test can detect infection even when you feel well.

Symptoms of TB in the lungs

When TB infects the lungs—the most common form—you experience chest pain that worsens when you breathe or cough. The cough may start dry and later produce sputum that looks clear, white, or tinged with blood. Shortness of breath can develop as the infection progresses and damages lung tissue.

The fever pattern is often distinctive: it rises in the afternoon or evening and returns to normal by morning. Night sweats can be so heavy that you soak through your clothes and sheets. These symptoms typically build over several weeks, and people often attribute them to a stubborn cold before seeking medical care.

TB symptoms outside the lungs

TB can spread to other parts of your body, and the symptoms depend on where the infection settles. TB of the lymph nodes (the small glands in your neck, armpits, and groin) causes swollen, tender lumps. TB of the bones or joints produces pain and swelling, often in the spine, hips, or knees. TB of the brain and spinal cord—called TB meningitis—causes severe headache, stiff neck, confusion, and sensitivity to light.

TB can also infect the kidneys, bladder, reproductive organs, or other tissues. Symptoms vary widely depending on the organ involved. For example, TB of the kidney may cause blood in the urine, while TB of the spine may cause back pain and neurological problems. A doctor needs to know your full symptom picture to identify where the infection is located.

The difference between latent and active TB

You can have TB bacteria in your body without feeling sick. This is called latent TB infection. The bacteria are dormant and cannot spread to others, but they can become active later. A skin test or blood test will show that you carry TB, even though you have no symptoms.

Active TB disease is when the bacteria multiply and cause illness. This is when symptoms appear and you can spread TB to others through the air when you cough, sneeze, or speak. About 5 to 10 percent of people with latent TB develop active disease at some point in their lives, often years after infection.

When to see a doctor

See a doctor if you have a cough that lasts more than three weeks, especially if it produces sputum or blood. Also seek care if you have fever, night sweats, or unexplained weight loss lasting more than a few weeks. These symptoms can point to TB or other serious conditions that need diagnosis.

Tell your doctor if you have been in close contact with someone who has TB, work in a setting with TB exposure, or have a weakened immune system. This information helps your doctor decide whether to test you. A simple skin test or blood test can determine whether you have TB infection.

Why TB symptoms take time to notice

TB grows slowly compared to other infections. The bacteria damage lung tissue gradually, so symptoms creep up over weeks. Many people ignore an early cough or attribute night sweats to stress or menopause. By the time symptoms feel serious enough to warrant a doctor visit, the infection may have progressed.

This slow progression is also why TB can spread without the infected person realizing they are sick. Someone with active TB may cough around family members, coworkers, or people on public transit for weeks before seeking care. Early diagnosis protects both the person with TB and those around them.

Symptoms in children and older adults

Children with TB may have milder or less obvious symptoms than adults. A child might have a persistent cough, low-grade fever, or failure to gain weight. The cough may not produce sputum, making it harder to spot. Older adults sometimes present with fatigue and weight loss as the primary signs, with a less prominent cough.

People over 65 and very young children are at higher risk for severe TB disease. If you notice these symptoms in a child or older adult, mention them to a doctor even if they seem minor. TB in these groups can progress quickly and cause serious complications.

Frequently Asked Questions

Can you have TB without a cough?

Yes. TB outside the lungs—such as in the lymph nodes, bones, or kidneys—may not cause a cough at all. You might have swelling, pain, or other symptoms specific to the infected area. A skin test or blood test can detect TB infection regardless of symptoms.

How long does it take for TB symptoms to appear?

Symptoms usually develop over weeks to months after infection. Some people develop active TB within weeks, while others carry latent TB for years before symptoms emerge. There is no fixed timeline; it depends on your immune system and the amount of bacteria exposure.

Is a TB cough contagious?

Yes, if you have active TB in the lungs, your cough spreads the bacteria through the air. You are most contagious when coughing, sneezing, or speaking. After taking TB medicine for about two weeks, most people stop being contagious, even though treatment continues for months.

Can TB cause only night sweats without a cough?

Night sweats alone are not typical of TB, though they can occur with it. TB usually causes a cough along with fever and sweats. Night sweats have many other causes, including hormonal changes, infections, and certain medications. A doctor can help determine the cause.

What should I do if I have symptoms that might be TB?

Contact your doctor and describe your symptoms, especially if a cough has lasted more than three weeks. Mention any known TB exposure or risk factors. Your doctor will likely order a skin test or blood test and may take a chest X-ray to look for signs of TB in the lungs.