Kikuchi's disease (KD), or histiocytic necrotizing lymphadenitis, was initially described in Japan in 1972. In the following years, several series of cases involving patients of different ages, races, and geographic origins were reported, but pediatric reports have been rare. The etiology of KD is unknown, although a viral or autoimmune hypothesis has been suggested. The most frequent clinical manifestation consists of local or generalized adenopathy, although in some cases, it is associated with more general symptoms, multiorganic involvement, and diverse analytic changes (leukopenia, elevated erythrocyte sedimentation rate, and C-reactive protein, as well as an increase of transaminases and serum lactic dehydrogenase). Diagnosis is based on characteristic pathologic findings that permit differentiation of this disease from lymphoma, systemic lupus erythematosus, and infectious lymphadenopathies. We present here the case of a 14-year-old boy who presented with severe systemic manifestations and transient fulminant hepatic failure in response to treatment with antituberculosis drugs. Kikuchi's disease, lymphadenitis, liver failure, antituberculosis drugs.