What is tuberculosis?

Tuberculosis (TB) is a bacterial infection usually affecting the lungs — causing persistent cough, weight loss, night sweats, and fever. It spreads through close prolonged contact via cough droplets. Latent TB has no symptoms but can reactivate — treated to prevent active disease. Active TB needs months of antibiotics — usually 6 months combination therapy on the NHS. See a GP if you have cough over 3 weeks with weight loss or night sweats, or if you were born in or travelled to high-TB countries.

What are the symptoms of tuberculosis?

Persistent cough over 3 weeks — sometimes blood-streaked sputum, night sweats, weight loss, loss of appetite, fever, fatigue, chest pain. Extrapulmonary TB affects lymph nodes, spine, brain, kidneys — symptoms vary by site. Many latent cases have no symptoms.

How do you catch tuberculosis?

Inhaled droplets from cough or sneeze of person with active pulmonary TB — usually requires prolonged close contact in enclosed spaces — household, prison, some workplaces. Not spread by brief casual contact, plates, or toilet seats. Latent TB is not contagious.

What is the difference between latent and active TB?

Latent — bacteria dormant, no symptoms, not infectious, positive skin or blood test. Active — bacteria multiplying, symptoms, infectious — needs treatment and public health contact tracing. Latent can reactivate to active — especially if immunosuppressed.

How is tuberculosis treated?

Active pulmonary TB — typically 6 months antibiotics — isoniazid, rifampicin, ethambutol, pyrazinamide combination initially, then continuation phase. Directly observed therapy ensures adherence. Latent TB — shorter regimens (e.g. 3 months isoniazid/rifapentine) for those at high reactivation risk.

Is there a vaccine for TB?

BCG vaccine given at birth in areas with high TB rates or to at-risk babies — partial protection against severe childhood TB — not fully protective against adult pulmonary TB. Not part of routine UK schedule in low-incidence areas.

Can TB come back after treatment?

Relapse uncommon if full course completed correctly. Reinfection possible in high-exposure settings. Drug-resistant TB harder to treat — emphasises completing standard treatment first time.

Tuberculosis: Symptoms, Causes & Treatment

Tuberculosis (TB) — still present in the UK

Tuberculosis is infection with Mycobacterium tuberculosis — most often lungs (pulmonary TB) but can affect any organ (extrapulmonary TB).

UK incidence is low compared globally but concentrated in urban areas and migrant communities from high-prevalence countries. Drug-sensitive TB is curable — treatment requires months of antibiotics and public health support.

Pulmonary TB symptoms

Classic triad:

persistent cough >3 weeks
weight loss
night sweats

Also:

haemoptysis — blood in sputum
fever, fatigue
chest pain, breathlessness

Insidious onset — weeks to months — not sudden like pneumonia.

Extrapulmonary TB

Site	Features
Lymph nodes	Painless neck swelling — scrofula
Spine (Pott disease)	Back pain, deformity
Brain (TB meningitis)	Headache, meningism — emergency
Abdominal	Pain, weight loss
Genitourinary	Sterile pyuria

HIV co-infection — atypical presentation, faster progression — see HIV guide.

Latent vs active

Latent TB infection (LTBI):

positive IGRA/Mantoux blood or skin test
normal chest X-ray
no symptoms
not infectious
treatment offered if high reactivation risk — immunosuppression, recent conversion

Active TB:

symptoms + microbiology (culture, PCR) or strong clinical/radiological evidence
notifiable — contact tracing
chest X-ray — upper lobe cavitation classic

Diagnosis

chest X-ray
sputum — auramine stain, culture, GeneXpert MTB/RIF — rapid resistance detection
IGRA blood test (interferon-gamma release assay) — latent screening
HIV test — all TB patients

Treatment

Standard active pulmonary TB ( drug-sensitive):

6 months combined antibiotics
initial 2 months: RIPE — rifampicin, isoniazid, pyrazinamide, ethambutol
continuation 4 months: rifampicin + isoniazid

Directly Observed Therapy (DOT) — nurse watches doses — ensures completion.

Side effects:

liver toxicity — monitor LFTs
orange body fluids — rifampicin
neuropathy — isoniazid — pyridoxine co-prescribed

MDR-TB — resistant to rifampicin/isoniazid — specialist centre, longer regimens.

Never stop early — breeds resistance.

Prevention

BCG — selected infants/high-risk
screening new entrants from high-prevalence countries
treat latent TB in immunosuppressed before biologics
ventilation in high-risk settings

When urgent

massive haemoptysis
respiratory failure
TB meningitis suspicion — 999
MDR-TB — isolation, specialist

TB is slow, treatable, and stigmatised — 3-week cough with weight loss in at-risk groups deserves chest X-ray and sputum, not repeated antibiotics alone.

Common questions about tuberculosis

What are the symptoms of tuberculosis?: Persistent cough over 3 weeks — sometimes blood-streaked sputum, night sweats, weight loss, loss of appetite, fever, fatigue, chest pain. Extrapulmonary TB affects lymph nodes, spine, brain, kidneys — symptoms vary by site. Many latent cases have no symptoms.
How do you catch tuberculosis?: Inhaled droplets from cough or sneeze of person with active pulmonary TB — usually requires prolonged close contact in enclosed spaces — household, prison, some workplaces. Not spread by brief casual contact, plates, or toilet seats. Latent TB is not contagious.
What is the difference between latent and active TB?: Latent — bacteria dormant, no symptoms, not infectious, positive skin or blood test. Active — bacteria multiplying, symptoms, infectious — needs treatment and public health contact tracing. Latent can reactivate to active — especially if immunosuppressed.
How is tuberculosis treated?: Active pulmonary TB — typically 6 months antibiotics — isoniazid, rifampicin, ethambutol, pyrazinamide combination initially, then continuation phase. Directly observed therapy ensures adherence. Latent TB — shorter regimens (e.g. 3 months isoniazid/rifapentine) for those at high reactivation risk.
Is there a vaccine for TB?: BCG vaccine given at birth in areas with high TB rates or to at-risk babies — partial protection against severe childhood TB — not fully protective against adult pulmonary TB. Not part of routine UK schedule in low-incidence areas.
Can TB come back after treatment?: Relapse uncommon if full course completed correctly. Reinfection possible in high-exposure settings. Drug-resistant TB harder to treat — emphasises completing standard treatment first time.

Sources

How we reviewed this page

Medically reviewed by the HealthAnswers UK doctor review panel

First published: 14 June 2026
Medically reviewed: 3 July 2026
Next review due: 3 July 2029 or sooner if NHS or NICE guidance changes

Written by HealthAnswers editorial team. Published by HealthAnswers (Elite Digital AI Solutions Ltd). How we review content · Report a problem with this page