Fixed drug eruption to ingested propolis.

Area of Science:

• Dermatology
• Allergology
• Pharmacovigilance

Background:

• Fixed drug eruptions (FDEs) are characterized by recurrent skin lesions at specific sites after drug re-exposure.
• While numerous drugs are known FDE culprits, recent attention has focused on herbal medications and food additives.
• Propolis, a known contact allergen, had not previously been linked to FDE.

Observation:

• A patient presented with a year-long history of a recurrent penile lesion.
• The patient tested positive for propolis allergy and reported using a herbal supplement containing it.
• Discontinuation of the supplement led to lesion resolution, with recurrence upon rechallenge.

Findings:

• The patient's recurrent penile lesion was biopsy-proven to be a fixed drug eruption.
• Patch testing with propolis elicited a reaction at the test site, not the previous lesion site.
• Systemic rechallenge with the herbal supplement confirmed propolis as the causative agent for the FDE.

Implications:

• This case identifies propolis as a novel cause of fixed drug eruptions.
• It underscores the importance of considering non-traditional agents, like herbal supplements, in FDE diagnosis.
• The findings highlight the diagnostic value of patch testing and systemic rechallenge in identifying FDE triggers.