Allergic contact dermatitis to cinchocaine.

Area of Science:

• Dermatology
• Allergology
• Pharmacology

Background:

• Topical anesthetic agents are widely used for symptomatic relief.
• Classification and cross-reactivity patterns among these agents can be complex.
• Accurate diagnosis of allergic contact dermatitis is crucial for patient management.

Observation:

• A patient presented with acute perianal dermatitis after using Proctosedyl ointment.
• The dermatitis was suspected to be allergic contact dermatitis.
• Patch testing was performed to identify the causative agent.

Findings:

• The patient exhibited allergic contact dermatitis to cinchocaine, an ingredient in Proctosedyl ointment.
• Positive reactions were observed to cinchocaine and the Proctosedyl ointment itself.
• No allergic reaction was noted to benzocaine or lignocaine during patch testing.

Implications:

• This case underscores the diagnostic challenges in topical anesthetic allergy.
• It questions the adequacy of benzocaine as a sole screening agent for contact allergy to topical anesthetics.
• Further research into cross-reactivity patterns among topical anesthetics is warranted.