History and classification of anaphylaxis

Area of Science:

• Allergy and Immunology
• Clinical Medicine

Background:

• Anaphylaxis is a severe, acute allergic reaction impacting multiple organ systems.
• Historically recognized and named in the early 20th century, it involves a spectrum of symptoms.

Observation:

• Symptoms commonly begin in the skin and progress to respiratory, gastrointestinal, and cardiovascular systems, potentially leading to arrest.
• Reactions can be IgE-mediated (immunological) or pseudo-allergic (anaphylactoid) without detectable sensitization.
• Common triggers include drugs, foods, additives, and physical factors; reaction severity is influenced by sensitization and co-factors like infection or stress.

Findings:

• Anaphylaxis can be triggered by diverse allergens and physical factors.
• Co-factors such as infection, exercise, stress, or medications can exacerbate or precipitate anaphylaxis.
• Decreased plasma angiotensin levels correlate with severity in insect venom anaphylaxis.
• Allergy diagnosis is crucial to identify triggers and mechanisms, guiding alternative options and treatment.

Implications:

• Accurate diagnosis of anaphylaxis is essential for patient management and prevention of future reactions.
• Allergen-specific immunotherapy offers a highly effective causal treatment for IgE-mediated anaphylaxis, with high success rates in insect venom allergy.
• Understanding contributing factors like "summation anaphylaxis" is vital for managing complex or idiopathic cases.