Erythema dyschromicum perstans and the betel nut

Introduction: Erythema dyschromicum perstans is a dermatosis characterised by hyperpigmented ashen-gray macules of variable size. The exact aetiology is unknown, however has been implicated with medications, viral infections, and chemical toxicity.
Case: A 24-year old Burmese male presented with a 3 and a half year history of a rash affecting his neck, back and abdomen. The rash was mostly asymptomatic with occasional pruritus.
He was otherwise well and was a non-smoker, non-drinker. He noted that he had chewed betel nut with limestone paste and betel leaf for over twelve years duration. He was not taking any current medications. His examination showed reticulate hyperpigmented patch on the anterior chest, left neck, mid upper back, and lumbar region of the lower back. There was mild scale with few erosions.
Histopathology showed a dermatitis with prominent pigmentary incontinence. There was lymphocytic inflammatory infiltrate in the superficial dermis. Rare eosinophils were noted in the mid-dermis. There was no amyloid deposition. PAS stain and fungal elements were negative. While histology was not diagnostically specific, the overall clinical impression was consistent with Erythema dyschromium perstans.
Discussion: To our knowledge, this is the first reported case of Eyrthema dyschromium perstans associated with betel nut. Reported causes include medication exposure, radiographic contrast, pesticides, Trichuris trichuria infestation, HIV infection, and toxicity of chemicals including ammonium nitrate or barium sulphate.
Conclusion: Eyrthema dyschromium perstans is a difficult diagnosis. This case highlights the importance of taking an extensive medication and substance use history which may aid in identifying the culprit agent.

Dr. Emily Shao