Yellow Granular Material in Hair: A Bedside Clue to Overdose from Cold Medication Containing Acetaminophen.

case presentationA 28-year-old woman was brought to the emergency department after being found collapsed at home. Because she was unable to provide a history, contextual bedside clues were important during the initial assessment. Bright yellow granular material with a medicinal odor was noted adherent to her hair. This unusual finding raised suspicion of overdose with an acetaminophen-containing over-the-counter (OTC) cold medication. Her serum acetaminophen concentration was elevated at 135 micrograms per milliliter, and N-acetylcysteine was promptly administered. She did not develop hepatic injury and was discharged after recovery. DISCUSSION: This case highlights the diagnostic value of visible bedside clues when history is initially unavailable. The yellow residue was not pathognomonic, and no chemical analysis of the material was performed. However, in the context of the increasing incidence of overdoses involving OTC medications in Japan, especially among young women, the finding was clinically sufficient to raise suspicion for possible ingestion of an OTC combination cold medication containing acetaminophen. This mattered because it directly prompted serum acetaminophen measurement and timely antidotal treatment with N-acetylcysteine, which can prevent or mitigate acetaminophen-induced liver injury.