Anaphylaxis to dextromethorphan with positive skin testing: a case report

Area of Science:

• Allergy and Immunology
• Pharmacology

Background:

• Dextromethorphan (DM) is a common cough suppressant found in many medications.
• Hypersensitivity reactions to DM, including rare cases of anaphylaxis, have been documented.
• Previous diagnostic approaches for DM allergy via skin testing have yielded mixed results.

Purpose of the Study:

• To report a rare case of anaphylaxis attributed to dextromethorphan (DM).
• To confirm DM as the causative agent through diagnostic skin testing.

Main Methods:

• A patient presented with a severe allergic reaction after ingesting an over-the-counter cold medicine.
• Skin prick testing was performed using components of the implicated medication.
• Diagnostic testing specifically identified dextromethorphan as the allergen.

Main Results:

• The patient experienced anaphylaxis following the consumption of a multi-ingredient cold and flu medication.
• Skin testing revealed a positive reaction exclusively to dextromethorphan (DM).
• Other ingredients, including acetaminophen, phenylephrine hydrochloride, and guaifenesin, did not elicit a reaction.

Conclusions:

• This case underscores the possibility of uncommon allergies to widely used combination cold medicines.
• Diagnostic skin testing is a valuable tool for identifying specific allergens like dextromethorphan in complex formulations.