[Idiopathic anaphylaxis]

Area of Science:

• Clinical Immunology and Allergy
• Emergency Medicine

Background:

• Idiopathic anaphylaxis (IA) is characterized by recurrent episodes of angioedema, urticaria, bronchospasm, digestive issues, and cardiovascular collapse.
• IA primarily affects adults, with a higher prevalence in females, and can be life-threatening due to laryngeal angioedema or hypotension.
• Distinguishing IA from other rare conditions like capillary leak syndrome, mastocytosis, and C1 esterase inhibitor deficiency is crucial.

Purpose of the Study:

• To delineate the diagnostic process for Idiopathic Anaphylaxis (IA).
• To explore potential, though unconfirmed, pathogenic hypotheses for IA.
• To review current emergency and daily management strategies for IA.

Main Methods:

• Clinical case descriptions and diagnostic procedures for IA.
• Exclusion of mimic pathologies and investigation of rare etiological triggers.
• Review of proposed pathogenic mechanisms and current treatment regimens.

Main Results:

• The diagnosis of IA is established after excluding numerous differential diagnoses.
• Exceptional causes such as unusual food allergies, exercise, parasitic, inhalant, or hormonal triggers are investigated.
• Proposed pathogenic hypotheses include mast cell mediator release, anti-IgE autoimmunity, and angiotensin II deficiency, none of which are confirmed.
• Emergency treatment involves epinephrine auto-administration; daily management with corticosteroids and antihistamines is common but lacks randomized trial validation.

Conclusions:

• The diagnostic pathway for IA involves excluding rare mimics and searching for unusual triggers.
• Unconfirmed hypotheses suggest mediator release, autoimmunity, or hormonal imbalances as potential causes.
• Current treatments are symptom-based, and the lack of robust immunological studies questions IA's status as a distinct entity.