Beau’s lines are characterized by which feature and what can cause them?

• A. Vertical ridges across the nail plate
• B. Discoloration with pits
• C. Horizontal ridges across the nail plate; can indicate systemic illness or trauma
• D. No ridges; nails appear smooth

Answer: (C)

Beau's lines appear as horizontal grooves that run across the entire nail plate. They form when the nail matrix temporarily stops producing new nail cells, often due to a systemic illness or physical trauma. As the nail continues to grow after the pause, a band shows up across the nail and may move outward over time. This is why they’re linked to events like severe illness, fever, malnutrition, infections, chemotherapy, or significant trauma to the nail or body. By contrast, vertical ridges are a different pattern not caused by a temporary growth pause, pits with discoloration point to conditions like psoriasis, and nails that are smooth would not show these horizontal bands.