Nonpigmenting fixed drug eruption: a new case due to betahistine

Area of Science:

• Dermatology
• Immunology

Background:

• Fixed drug eruption (FDE) is a cutaneous adverse drug reaction characterized by recurrent lesions at the same site upon re-exposure to the causative agent.
• FDE typically presents as a hyperpigmenting macule or plaque, although other clinical variants exist.

Observation:

• This report describes a case of a seldom-reported nonpigmenting subset of fixed drug eruption.
• This variant shares the characteristic fixed nature and well-demarcated margins with the pigmenting type.
• Distinct clinical and histological features differentiate the nonpigmenting FDE from its pigmenting counterpart, facilitating easier diagnosis.

Findings:

• The precise physiopathology of nonpigmenting FDE remains unclear.
• A delayed hypersensitivity mechanism is the suspected underlying cause for this reaction.
• The specific drugs that induce the nonpigmenting eruption are discussed within the report.

Implications:

• Recognition of the nonpigmenting FDE subtype is crucial for accurate diagnosis and management of adverse drug reactions.
• Understanding the distinct features aids clinicians in differentiating it from other dermatoses.
• Further research into the physiopathology may reveal novel therapeutic targets for FDE.