What term describes hypertrophy of the nailbeds due to chronic hypoxemia?

• A. Cyanosis
• B. Onychomycosis
• C. Clubbing
• D. Pitting edema

Answer: (C)

Clubbing describes the rounded, enlarged appearance of the distal end of the fingers and the nail beds that develops with chronic low oxygen levels. Over time, the soft tissue under the nail bed thickens and the nail plate becomes more curved, giving a bulbous, “drumstick” look. This change is a response to long-standing hypoxemia and is often seen with chronic lung diseases or cyanotic heart conditions.

It’s distinct from simple cyanosis, which is a color change due to deoxygenated blood but does not involve structural changes to the nails. It’s also not due to fungal infection of the nails (onychomycosis) or fluid buildup in the extremities (pitting edema).