Mees' lines are associated with poisoning by which metal?

• A. Arsenic
• B. Mercury
• C. Zinc
• D. Silver

Answer: (A)

Mees' lines are white transverse bands that appear across the nails when there has been arsenic exposure. They form because arsenic disrupts nail matrix activity during a period of systemic poisoning; as the nail grows, the damaged row of keratin shows up as a white stripe that slowly moves distally with growth. This pattern is classically linked to arsenic poisoning, making it the best match among the options. Other metals like mercury, zinc, or silver don’t produce this characteristic nail sign in the same way. Note that Mees' lines are distinct from other nail changes, such as Beau's lines, which are depressions rather than white bands.