Immunotherapy Safety for the Primary Care ... - U.S. Coast Guard

2) Anaphylatoxins: C3a and C5a
3) Drugs: Certain drugs act directly on the mast cell to release its mediators.
Classification of Anaphylaxis: Most classification systems utilize these three mechanisms of
mediator release to classify the various types of anaphylaxis:
1) IgE mediated anaphylaxis
2) Complement activated anaphylaxis
3) Mast cell/basophil activated anaphylaxis
4) Unknown/Idiopathic anaphylaxis
Anaphylaxis vs anaphylactoid: The term anaphylaxis is frequently used to refer only to IgEmediated,
mast cell activation, whereas anaphylactoid reactions are used to denote the
other non-IgE mediated responses. However, both events are clinically and
biochemically similar; therefore, the term “anaphylaxis” is often used interchangeably for
both clinical syndromes.
Components of an IgE anaphylactic response:
1) Exposure to a sensitizing antigen
2) An IgE-class antibody response, resulting in systemic sensitization of mast cells or
basophils
3) Reintroduction of the sensitizing antigen
4) Mast cell degranulation (with mediator release/generation)
5) Pathologic responses: anaphylaxis.
Examples of IgE-Mediated Reactions
1) Medications
• Penicillin: Penicillin and other beta-lactam antibiotics account for more
than 75% of cases of anaphylaxis from medication.
• Most frequent cause of anaphylaxis: 400-800 deaths annually.
• 1 case/2,500 course of penicillin given.
• Skin testing: predictive.
• Local anesthetics:
Reactions to local anesthetics are common; however, IgE mediated
reactions are exceedingly rare. Most reactions are due to vasovagal, toxic,
or idiosyncratic responses rather than true allergic reactions.
Hypersensitivity more common with the preservatives in the anesthetic:
parabens and sulfites.
2) Foreign proteins (horse serum, chymopapain, latex)
Latex: becoming especially important with the widespread use of latex gloves. It
is particularly common in patients with spina bifida or congenital urologic
abnormalities because of frequent exposure to urinary catheters and
frequent operations. Should be considered whenever an intraoperative
reaction occurs.
3) Foods (peanuts, nuts, fish, shellfish, egg, and milk) Concomitant asthma is an
important risk factor.