Etoricoxib-induced fixed drug eruption with positive lesional patch tests

Area of Science:

• Dermatology
• Pharmacology

Background:

• Fixed drug eruption (FDE) is a common cutaneous reaction, typically associated with antibiotics, anticonvulsants, and nonsteroidal anti-inflammatory drugs (NSAIDs).
• Cyclooxygenase 2 (COX-2) inhibitors are less frequently implicated in FDE.
• Etoricoxib is a newer COX-2 inhibitor used for pain management.

Observation:

• A 52-year-old woman presented with recurrent, erythematous, pruritic plaques on her neck, forearm, and finger, which healed with hyperpigmentation.
• The lesions consistently reappeared in the same locations after sporadic oral administration of etoricoxib (90 mg) for back pain.
• The time interval between etoricoxib intake and lesion appearance progressively shortened.

Findings:

• Patch tests with etoricoxib (1% and 5% in petrolatum) were positive on lesional skin and negative on nonlesional skin.
• Standard European and NSAID series patch tests were negative.
• Patch tests in 10 healthy controls using etoricoxib were negative, supporting etoricoxib as the causative agent for FDE in this patient.

Implications:

• Patch testing with etoricoxib proved reliable for diagnosing FDE, obviating the need for potentially risky oral provocation tests.
• This case underscores that even drugs considered safe, like etoricoxib, can cause cutaneous adverse reactions, including FDE.
• Clinicians should consider FDE when evaluating patients presenting with recurrent skin lesions potentially linked to COX-2 inhibitor use, especially given the increasing prescription of these agents for pain control.