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

Background

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.

Objective

To better define the presentation and understand the potential relationship between US-IA and underlying psychiatric comorbidities.

Methods

We retrospectively reviewed 110 visits by 107 patients to our institution for evaluation and management of anaphylaxis over a 1-year period. The patients were classified as having either criteria positive (CP) or criteria negative (CN) anaphylaxis based on whether they met Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network Symposium criteria for the clinical diagnosis of anaphylaxis. Patient characteristics, including objective and subjective signs and symptoms, and the presence of psychiatric diagnoses were collected and analyzed. Statistical significance was assessed by using the Fisher exact test. A literature review of US-IA and other psychogenic forms of anaphylaxis was performed.

Results

Patients with CP anaphylaxis were more likely to present with hypotension, wheezing, urticaria, and vomiting than were patients with CN anaphylaxis. The patients with CN anaphylaxis were more likely to present with subjective symptoms of sensory throat tightness or swelling compared with patients with CP anaphylaxis. No significant difference was detected in the prevalence of psychiatric conditions between the two groups.

Conclusion

Patients who met previously established diagnostic criteria for anaphylaxis were more likely to present with objective physical findings than those who did not meet criteria for true anaphylaxis. CN patients who presented for treatment of anaphylaxis were more likely to present with subjective symptoms. Formal diagnostic criteria should be used by clinicians when evaluating patients with suspected anaphylaxis.