Criteria positive and criteria negative anaphylaxis, with a focus on undifferentiated somatoform idiopathic anaphylaxis: A review and case series.

Undifferentiated somatoform (US) idiopathic anaphylaxis (IA) is considered a psychogenic disorder characterized by a lack of observable physical findings and poor response to treatment. Although failure to diagnose true anaphylaxis can have disastrous consequences, identification of US-IA is crucial to limit unnecessary expenses and use of health care resources. To better define the presentation and understand the potential relationship between US-IA and underlying psychiatric comorbidities.