What tuberculosis symptoms look like

Tuberculosis (TB) causes a persistent cough that lasts three weeks or longer. The cough often brings up sputum—phlegm or mucus—and sometimes blood. You may also run a fever, especially in the afternoon or evening, and sweat heavily at night, sometimes enough to soak your clothes or sheets. These symptoms develop slowly over weeks, not suddenly like flu.

Beyond the cough and fever, TB causes fatigue and weakness that makes ordinary tasks feel exhausting. You may lose your appetite and lose weight without trying. Chest pain or discomfort when breathing or coughing is common. The combination of a long-lasting cough, night sweats, and weight loss is the pattern that should prompt you to see a doctor.

Not everyone with TB infection shows symptoms. Latent TB means the bacteria are in your body but inactive, and you have no symptoms and cannot spread the disease. Active TB means the bacteria are multiplying and causing illness. Only active TB produces the symptoms described here.

Key Takeaways

  • A cough lasting three weeks or longer, especially one that brings up blood or mucus, is the most common TB symptom and a reason to see a doctor.
  • Night sweats, afternoon fevers, fatigue, and unexplained weight loss often occur together with TB cough and point toward TB rather than other illnesses.
  • Symptoms develop gradually over weeks, not suddenly, which is why TB is sometimes missed at first.
  • You can have TB bacteria in your body without any symptoms (latent TB), but only active TB causes illness and spreads to others.
  • Chest pain when breathing or coughing, combined with other symptoms, warrants a doctor visit to rule out TB.

When the cough is the main warning sign

The cough is almost always present in active TB. It starts dry and may stay that way for weeks, then progress to producing sputum. If the sputum contains blood—even small amounts—that is a strong signal to seek medical attention. Some people cough up blood without other symptoms being severe, which can be alarming but is not uncommon in TB.

The cough does not respond to over-the-counter cough medicine or antibiotics for common bacterial infections. If you have taken cough medicine or finished a course of antibiotics and the cough persists beyond three weeks, TB becomes a possibility worth investigating. Smokers and people with other lung conditions sometimes dismiss a cough as related to smoking or asthma, which can delay diagnosis.

Fever and night sweats as TB indicators

TB fever is often low-grade—around 99 to 101 degrees Fahrenheit—and tends to spike in the late afternoon or evening, then drop at night. This pattern differs from acute infections, which usually cause higher fevers throughout the day. The fever may come and go rather than staying constant.

Night sweats in TB are often drenching enough that you wake up soaked and need to change clothes or bedding. They happen because your immune system is fighting the infection. Night sweats alone are not specific to TB—they occur in many conditions—but combined with a persistent cough and weight loss, they form a recognizable pattern.

Weight loss and fatigue without obvious cause

TB causes your body to burn calories as it fights infection, leading to weight loss even if you are eating normally. You may notice your clothes fitting differently or the scale dropping over several weeks. This weight loss is not intentional and happens alongside the other symptoms.

The fatigue is often profound. People with active TB describe feeling too tired to work a full day or manage household tasks. Rest does not relieve it the way it does with normal tiredness. If you are losing weight and feeling exhausted while also coughing, and these changes have developed over weeks, a doctor should evaluate you.

Chest pain and breathing difficulty

TB can cause chest pain or discomfort, especially when you cough or take a deep breath. The pain may feel sharp or dull and can be on one side of the chest or spread across it. Some people describe it as a tightness in the chest rather than sharp pain.

Shortness of breath can occur, though it is less common than cough. If TB damages lung tissue or causes fluid to build up around the lungs, breathing becomes harder. Chest pain combined with cough and fever should be evaluated promptly, as several serious conditions can cause this combination.

How symptoms differ between children and adults

Children with active TB may have milder symptoms than adults, or symptoms that are harder to notice. A child might have a persistent cough but no fever, or fever without cough. Weight loss or failure to gain weight at the expected rate can be the main sign in young children.

Children are also more likely to have TB that spreads beyond the lungs—to the brain, bones, or lymph nodes—because their immune systems are still developing. This is why any persistent cough in a child, even without fever or weight loss, warrants investigation if the child has been exposed to someone with TB.

When symptoms mean you should see a doctor

See a doctor if you have a cough lasting three weeks or longer, regardless of other symptoms. You do not need to wait for fever or weight loss to develop. A cough that long is not normal and has many possible causes, but TB is one that needs to be ruled out.

Seek urgent care if you cough up blood, have severe chest pain, or feel short of breath. These symptoms can indicate TB or other serious lung conditions. If you know you have been exposed to someone with active TB, tell your doctor that fact when you call or visit, so they can prioritize testing.

Frequently Asked Questions

Can you have TB without a cough?

Yes. Latent TB causes no symptoms at all. In active TB, cough is the most common symptom but not universal—some people have TB that affects areas outside the lungs (like bones or lymph nodes) and may not cough. However, if you have active TB in the lungs, a cough almost always develops.

How long does it take for TB symptoms to show up?

Symptoms can appear weeks to months after infection. Some people develop active TB within weeks of exposure; others may have latent TB for years before symptoms start. There is no fixed timeline. If you were exposed to TB, your doctor can test you even without symptoms.

Is TB cough contagious?

Yes. When someone with active TB coughs, sneezes, or speaks, they release droplets containing TB bacteria into the air. People nearby can breathe in these droplets and become infected. This is why anyone with a persistent cough should see a doctor—to protect others as well as themselves.

Can TB cause symptoms in just one lung?

TB usually starts in one lung but can spread to both. You might feel chest pain or discomfort on one side where the infection is active. Imaging tests show which lung or lungs are affected, but symptoms alone do not reliably indicate whether one or both lungs are involved.

What if I have some TB symptoms but not all of them?

You do not need every symptom to have TB. Some people have only cough and fever; others have cough and night sweats but no fever. Any combination of persistent cough, fever, night sweats, weight loss, or chest pain warrants a doctor visit and testing if TB exposure is possible.