[Allergic reaction to topical drugs]

Area of Science:

• Dermatology
• Allergology
• Contact Dermatitis

Background:

• Cutaneous eruptions can worsen due to topical therapy, mimicking lack of response.
• Differentiating true lack of response from allergic contact dermatitis is clinically significant.

Purpose of the Study:

• To identify the specific allergenic compounds in topical medications causing contact dermatitis.
• To determine the prevalence of specific allergens responsible for positive patch test reactions.

Main Methods:

• A study involving 87 patients diagnosed with contact dermatitis secondary to topical therapy.
• Patch testing was performed using sixteen known allergenic chemical compounds.

Main Results:

• Eight chemical compounds accounted for 86.5% of positive patch test reactions.
• Neomycin, ethylenediamine, and mercury were the most frequent allergens, responsible for over half of all reactions.
• Other significant allergens included benzocaine, iodochlorhydroxyquin, Peruvian balsam, nitrofurazone, and cinchocaine.

Conclusions:

• Knowledge of topical medication composition and ingredient allergenicity is crucial for diagnosing contact dermatitis.
• Identifying common allergens like neomycin, ethylenediamine, and mercury can improve diagnostic accuracy and patient management.