The clinical entity essential thrombocytopenic purpura (idiopathic or primary purpura haemorrhagica) is a condition of unknown etiology. A similar condition of known etiology is referred to as secondary or symptomatic thrombocytopenic purpura. Both these forms of purpura manifest a general hemorrhagic tendency, and the conspicuous feature is a definite diminution of the blood platelets. From the standpoint of treatment it is important therefore to determine if possible, by careful investigation, the exciting causative factor of thrombocytopenia. It is well to recall that there is also a number of conditions in which purpura occurs in the absence of a general hemorrhagic tendency and diminution of platelets. These purpuras according to Christian,1can be classified into essential (idiopathic) and secondary (symptomatic) nonthrombocytopenic purpura. The term purpura implies cutaneous hemorrhage. One of the important and clinically interesting subgroups of essential nonthrombocytopenic purpura is the so-called anaphylactoid purpura,2which includes the Schönlein-Henoch