MULTIFOCAL FIXED DRUG ERUPTION MIMICKING ACQUIRED DERMAL MELANOCYTOSIS

Area of Science:

• Dermatology
• Pharmacology
• Pathology

Background:

• Fixed drug eruptions (FDEs) are a prevalent type of adverse drug reaction characterized by recurrent skin lesions upon re-exposure to a specific causative agent.
• FDEs commonly affect young adults and can present as single or multiple lesions, often followed by post-inflammatory hyperpigmentation.
• The clinical presentation of FDEs can vary, making them susceptible to misdiagnosis as other dermatological conditions.

Observation:

• A case of multifocal fixed drug eruption is presented following the oral administration of Loratadine, Cetirizine dihydrochloride, Ibuprofen, and/or Acetylsalicylic acid.
• The patient declined patch testing, a common diagnostic tool for FDEs.
• A punch biopsy was performed, confirming the diagnosis of multifocal fixed drug eruption.

Findings:

• The case demonstrates that common over-the-counter medications can trigger multifocal FDEs.
• Histopathological examination via punch biopsy is crucial for confirming the diagnosis when patch testing is not feasible.
• The differential diagnosis of FDEs includes conditions such as acquired dermal melanocytosis and other cutaneous eruptions.

Implications:

• This case underscores the importance of considering FDEs in the differential diagnosis of various skin eruptions, especially in young adults.
• Awareness of FDEs induced by commonly used drugs like ibuprofen and antihistamines is essential for clinicians.
• Further investigation into the pathomechanisms of these drugs in FDEs is warranted to improve patient management and prevention strategies.