Vitamin B12-induced acneiform eruption.

Cutaneous acneiform eruptions are a side effect of many medications, including vitamin B12 therapy. However, reports of vitamin B12-induced acne are rare. We present a 67-year-old woman with a new diagnosis of pernicious anemia who developed a sudden acneiform eruption on the face after treatment with high-dose vitamin B12. Other medications that have been implicated in drug-induced acne include but are not limited to steroids, antibiotics, immunosuppressants, biologics, and vitamin B1 and B6. The pathogenesis is likely due to a transcriptome change in Propionibacterum acnes, the organism responsible for acne vulgaris. Cessation of the offending agent leads to a regression in symptoms.