Unintended consequences: mandatory tuberculin skin testing and severe isoniazid hepatotoxicity

After mandatory school-enrollment tuberculin skin testing, a 4-year-old girl who was at low risk for Mycobacterium tuberculosis infection had severe isoniazid hepatotoxicity that was managed with a liver transplant. Although severe isoniazid hepatotoxicity is very uncommon in children, this case emphasizes the need to limit skin testing to persons who have a risk factor for infection and to educate parents on how to monitor for adverse effects during treatment.