Sympathomimetic drug allergy: cross-reactivity study by patch test.

Area of Science:

• Dermatology
• Pharmacology
• Allergy & Immunology

Background:

• Sympathomimetic drugs, primarily alpha-adrenergic agents, are widely used for vasoconstriction, nasal decongestion, and mydriasis.
• Allergic reactions to sympathomimetics are uncommon, particularly with systemic use.
• Existing data on cross-reactivity among catecholamine derivatives are conflicting.

Purpose of the Study:

• To investigate the potential for cross-reactivity among various sympathomimetic drugs using patch testing.
• To determine the extent of sensitization to different sympathomimetic agents in patients with a history of allergy.

Main Methods:

• Patch tests were performed on 14 patients with documented allergies to sympathomimetic drugs.
• A range of sympathomimetic drugs, including phenylephrine, pseudoephedrine, ephedrine, and others, were tested at specified concentrations in petrolatum or dimethyl sulfoxide (DMSO).
• Dimethyl sulfoxide (DMSO) served as the negative control.

Main Results:

• Over 90% of patients exhibited positive patch test reactions to at least two different sympathomimetic drugs.
• A significant majority of patients (64.3%) were cross-sensitized to three or more drugs, and 57.1% to four or more.
• Patients with generalized rashes from oral pseudoephedrine showed greater cross-reactivity compared to those with localized contact dermatitis.

Conclusions:

• There is substantial cross-reactivity among the tested sympathomimetic drugs.
• Cross-reactivity is particularly notable when these drugs are administered systemically.
• Findings suggest a common sensitization pattern within this drug class.