Viral-associated immune thrombocytopenic purpura.

Chronic immune thrombocytopenic purpura (CITP) is a diagnosis of exclusion that occurs either de novo or secondary to other underlying disorders. Chronic infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are now well-characterized causes of CITP. Between 6% and 15% of patients infected with HIV may develop thrombocytopenia. Patients with CITP with risk factors for HIV infection should be screened for the virus. Treatment of HIV-related CITP should be directed toward antiviral therapy with highly active antiretroviral therapy (HAART) regimens. Hepatitis C viral infection can also be associated with chronic thrombocytopenia, even in the absence of overt liver disease. While HCV-related thrombocytopenia is typically less severe than primary CITP, affected patients are at greater risk of major bleeding. Sustained suppression of HCV virus with interferon-ribavirin therapy can improve platelet counts. Screening for HCV infection should be considered in patients with ITP with risk factors for infection, from regions with high rates of infection or in patients with unexplained mild elevations of liver enzymes.