Case of atopic dermatitis concurrent with idiopathic thrombocytopenic purpura, whose serum thymus and activation-regulated chemokine level remained undetectable

We report a 9-year-old Japanese female patient with atopic dermatitis associated with idiopathic thrombocytopenic purpura. She demonstrated high serum immunoglobulin (Ig)E and IgE specific to several environmental allergens, but extremely low serum thymus and activation-regulated chemokine (TARC) levels regardless of the disease progression. This case suggests platelets as the main source of serum TARC.