Herbal Teas and Thrombocytopenia: A Curious Case of Yellow Dock and Burdock-Induced Thrombocytopenia

Immune thrombocytopenia (ITP) is a bleeding disorder characterized by a decreased number of platelets. It is an immune system-mediated condition, with formation of antibodies against a structural platelet antigen. Although the pathogenesis remains elusive, primary disease is idiopathic and comprises 80% of cases. However, quite a few secondary causes have been established including Helicobacter pylori, varicella-zoster virus and cytomegalovirus. A few cases with an incidental association with herbal medications have been reported, but this causality has not been studied in detail. Here we present the case of 38-year-old African-American woman who presented with symptomatic thrombocytopenia, with a platelet count of 5 K/μl 1 week after she had consumed herbal tea containing Rumex crispus (yellow dock) and Arctium lappa (burdock). The association between unstudied herbs and ITP needs further research, given the widespread use of these substances and ongoing public uncertainty about their benefits. LEARNING POINTS: Over-the-counter herbal products marketed as having beneficial effects are not always harmless and can have clinically significant side effects. When investigating the causes of thrombocytopenia, physicians should be aware of and search for this rare cause. Treatment for herbal tea-induced thrombocytopenia is the same as for immune thrombocytopenia (i.e., steroids and platelet transfusion if there is actively bleeding).