Management of Positive TB Skin Test

Introduction to Latent TB Infection Treatment

All persons with a positive tuberculin skin test must receive treatment for latent TB infection unless prior treatment can be documented or active TB disease is ruled out first, as recommended by the Infectious Diseases Society of America 1, 2

Obtain a chest radiograph immediately for all persons with a positive tuberculin skin test, regardless of symptoms, to rule out active TB disease 3
Assess for TB symptoms: cough, hemoptysis, fever, night sweats, weight loss, chest pain, shortness of breath, and fatigue, as recommended by the European Respiratory Society 4

The definition of "positive" depends on the patient's risk factors, with ≥5 mm induration considered positive for HIV-infected persons, recent TB contacts, and immunosuppressed patients, as defined by the Centers for Disease Control and Prevention 1, 5
≥10 mm induration is considered positive for recent immigrants from high-prevalence countries, injection drug users, and residents of congregate settings, as defined by the Centers for Disease Control and Prevention 1, 5

The American Thoracic Society recommends 3 months of weekly rifapentine plus isoniazid (3HP) as a first-line regimen, with highest adherence rates and effective in reducing TB incidence by 36% in HIV-negative patients with TB contact history 1, 4
3-4 months of daily rifampin plus isoniazid (3-4RH) is also recommended, reducing TB incidence by 48% in HIV-positive patients, as recommended by the Infectious Diseases Society of America 1, 4
4 months of daily rifampin alone (4R) is recommended for its best adherence and acceptable efficacy, as recommended by the European Respiratory Society 1, 4

Administer pyridoxine (vitamin B6) with isoniazid-containing regimens to prevent peripheral neuropathy, especially in HIV-infected persons, pregnant women, diabetics, and alcoholics, as recommended by the Centers for Disease Control and Prevention 6
Monitor for hepatotoxicity, with Grade 3-4 liver toxicity most common with 9H, followed by 1HP and 6H, as recommended by the American Association for the Study of Liver Diseases 7

For high-risk contacts with initial negative test, the Centers for Disease Control and Prevention recommends immediate treatment for children <5 years and HIV-infected persons exposed to infectious TB, even with negative initial skin test 7, 9
For drug-resistant TB exposure, obtain drug susceptibility results from the index case before selecting a regimen, as recommended by the World Health Organization 10, 5