Leukonychia

What is it?

Leukonychia is the medical term for white discoloration of the nails. It is one of the most common nail findings, ranging from harmless white spots (often caused by minor trauma) to patterns that may signal an underlying health condition. Leukonychia is not a disease itself but a sign — a visible change that may point to anything from nail biting to liver or kidney disease.

A useful distinction is whether the whiteness comes from the nail plate itself (true leukonychia) or from the tissue beneath it (apparent leukonychia). In true leukonychia, pressing on the nail does not change the white appearance. In apparent leukonychia, the whiteness fades temporarily when pressure is applied — because the color change originates in the nail bed, not the nail plate.

What does it look like?

Leukonychia takes several forms:

• White spots (leukonychia punctata): Small, scattered white dots on the nail surface — the most common form, especially in children
• White bands (leukonychia striata): Horizontal white lines running across the nail, parallel to the base (lunula)
• Partially white nails: Large areas of the nail appear white, but some normal color remains
• Completely white nails (leukonychia totalis): The entire nail is white — a rare presentation

The white areas may be bright white or dull, and they can appear on one nail or several nails simultaneously. In true leukonychia, the white marks grow out with the nail and eventually disappear at the free edge. In apparent leukonychia, the white pattern stays in place regardless of nail growth.

Where does it appear?

• Fingernails: Most commonly affected; white spots from minor trauma are particularly frequent on the dominant hand
• Toenails: Less frequently noticed but can be involved, especially in cases related to shoes or systemic disease
• Single nail vs. multiple nails: Trauma typically affects one or a few nails; systemic causes tend to involve most or all nails simultaneously

Associated features

Leukonychia may be accompanied by:

• Other nail changes such as ridging, pitting, or brittleness (when part of a skin disease like psoriasis or alopecia areata)
• Signs of systemic illness — swelling, fatigue, jaundice, or changes in urine color (in kidney or liver disease)
• Nail surface irregularities — rough or crumbling nails may suggest a fungal infection causing white discoloration on the nail surface
• Hair loss or skin rashes (when associated with dermatological conditions)

When to see a doctor

Consider medical evaluation for:

• White discoloration affecting all or most nails — this may indicate liver disease, kidney disease, or a nutritional deficiency
• White horizontal bands on multiple nails after an illness, especially if accompanied by hair loss or fatigue
• White nails combined with a dark band at the tip (half-and-half nails) — associated with chronic kidney disease
• Nails that are mostly white with only a narrow pink strip at the tip (Terry's nails) — associated with liver disease
• White spots that do not grow out or change character over weeks
• Any nail color change accompanied by pain, swelling, or unusual symptoms elsewhere