When anaphylaxis occurs in the absence of an identifiable trigger, the anaphylactic reaction is termed idiopathic. It is a well-described type of anaphylaxis with treatment that is associated with good prognosis. Episodes may be reduced with prophylactic corticosteroids and antihistamines. There is no definitive diagnostic test for idiopathic anaphylaxis. By definition, it is a diagnosis of exclusion after eliminating other causes. Disorders that may mimic anaphylaxis should be considered for evaluation. The cause of idiopathic anaphylaxis remains uncertain. © 2011 Springer Science+Business Media, LLC.
Blatman, K. H., & Grammer, L. C. (2011). Idiopathic anaphylaxis. In Anaphylaxis and Hypersensitivity Reactions (pp. 223–234). Humana Press. https://doi.org/10.1007/978-1-60327-951-2_13