2025 – PAGE 105 – ALLERGY & IMMUNOLOGY

(DOUBLE TAKE) ANAPHYLAXIS

Anaphylaxis is a serious allergic reaction that is rapid in onset and may cause death according to the NIH and the Food Allergy & Anaphylaxis Network. The criteria generally require TWO systems to be affected in order to qualify for the definition of anaphylaxis. The one exception is when there is acute hypotension (may be evidenced by hypotonia or syncope), in which case the single finding can be used to define anaphylaxis. The four systems that can be affected minutes to hours after exposure to a suspected allergen include:

• Skin or mucosal involvement: Considered one system. Look for hives, itching, flushing or edema.
• Respiratory system: Look for wheezing, stridor, hyposmia or coughing.
• Continued GI symptoms: Look for vomiting or abdominal pain.
• Circulatory system compromise: Look for hypotension as evidenced by hypotonia, syncope or a drop in systolic blood pressure of > 30% (or a systolic blood pressure that is below the 70 mmHg + the child’s age in years).

The following is a review of some common issues to be aware of in case a child presents with anaphylaxis:

• FOOD EXPOSURE: Monitor for four hours for signs of rebound anaphylaxis after initial treatment. Children can potentially be monitored at home if they have a second dose of epinephrine available at home.
• RESPIRATORY COMPROMISE: When anaphylaxis is diagnosed, epinephrine should be given immediately in order to avoid respiratory compromise. If respiratory compromise already exists, then focus on securing the airway first and THEN focus on giving EPInephrine (1:1000, “3 zeroes for 3 letters of EPI”), diphenhydramine, IVF, and steroids.
• BETA BLOCKERS: They blunt the response to EPInephrine. Give glucagon to reverse the beta blocker effect and then give EPInephrine (again).
• ANAPHYLACTOID REACTIONS result from mast cell degranulation. These are not true IgE-mediated reactions. They may be seen with the use of NSAIDS, opiates, contrast, and vancomycin (in vancomycin flushing reaction, previously known as red man syndrome). Pretreat with steroids and diphenhydramine.

DRUG HYPERSENSITIVITY SYNDROME

Drug hypersensitivity syndrome is seen with Sulfa drugs, Dapsone, and Aromatic seizure medications. It results in Fever + Lymphadenopathy (LAD) + Rash ± Visceral involvement.

ANTICONVULSANT HYPERSENSITIVITY SYNDROME

Anticonvulsant hypersensitivity syndrome refers specifically to DRUG HYPERSENSITIVITY SYNDROME due to SEIZURE MEDICATIONS. Fever + Lymphadenopathy (LAD) + Rash ± Visceral involvement. This is seen with Carbamazepine, Phenobarbital, and Phenytoin. It can turn into STEVENS-JOHNSON SYNDROME (SJS) or TOXIC ENDODERMAL NECROLYSIS (TEN).