Treatment for TB Infection

The reason for treating a patient with asymptomatic tuberculosis infection is that there is a 5 percent risk for developing TB during the first year after infection and an additional 5 percent risk for developing TB over a lifetime. Also, treatment of asymptomatic TB infection is much simpler than treating tuberculosis.

The size of induration (swelling) and the clinical setting affect the likelihood that a positive PPD skin test represents a real infection. For instance, 5 mm of induration is significant in someone who has had recent contact with active TB, but not in a person without risk factors. The main indications for preventive therapy for tuberculosis-infected patients include the following:

  • PPD > 5 mm in the following patient groups:
    • Adults and children with HIV infection
    • Close contacts with infectious cases of TB
    • Patients with fibrotic lesions on chest x-ray
  • PPD > 10mm in the following patient groups:
    • Adults and children at risk for developing TB
    • Intravenous drug users
    • Immigrants from countries where tuberculosis is prevalent
    • Members of racial and ethnic minorities with an increasing incidence of tuberculosis
    • Medically under-served persons
    • Residents of long term care facilities, including prisons, mental institutions, and nursing homes
    • Patients with silicosis
    • Post-gastrectomy patients
    • Post-jejunoileal bypass patients
    • Malnutrition
    • Diabetes
    • Chronic renal failure
    • Immunosuppressive therapy (e.g., transplant patients)
    • Workers in health care facilities, hospital microbiology laboratories, schools, and daycare facilities
    • Children under age 4
  • Patients over age 35 with an increase > 15 mm in the area of PPD over 2 years
  • Patients under age 35 with an increase > 10 mm in area of PPD over 2 years
  • Patients with HIV infection exposed to an active case of TB, regardless of PPD reaction

Isoniazid TB Treatment

Treatment lasts 6 months in an adult without HIV, 12 months in an adult with HIV, and 9 months in children. This drug has side effects.

Rifampin TB Treatment

This is the second most commonly used drug. Generally, the course of therapy with rifampin is 6 to 12 months. If a patient has been exposed to multidrug-resistant Mycobacterium tuberulosis, individualization of drug therapy is required. Side effects have been noted with this drug.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 31 May 2000

Last Modified: 08 Oct 2015