Primary immune thrombocytopenia (ITP, also called idiopathic thrombocytopenic purpura, immune thrombocytopenic purpura) is an acquired thrombocytopenia caused by autoantibodies against platelet antigens. It is one of the more common causes of thrombocytopenia in otherwise asymptomatic adults.
Major diagnostic concerns in an adult with suspected ITP are distinguishing ITP from other causes of thrombocytopenia, which often have a similar presentation but may require completely different management approaches, and determining whether the ITP is primary or secondary to an underlying condition that might also benefit from treatment.
The lack of a sensitive or specific diagnostic test for ITP, and large number of other potential causes of thrombocytopenia, some of which may be overlooked (eg, drug-induced, congenital platelet disorder), also contribute to the challenges in diagnosing ITP.
Here we discuss the clinical manifestations and diagnosis of primary ITP in adults, as well as the differential diagnosis of ITP and causes of "secondary ITP" due to other conditions.
Other issues are discussed in separate topic reviews: