What causes dents in fingernails?

Not medical advice: Dents (indentations) that run horizontally across all 10 fingernails are actually called Beau’s lines. These are caused by an injury, a nail fold infection, illness, uncontrolled diabetes, or malnourishment.

Beau’s lines shouldn’t be confused with horizontal Muehrcke’s fingernail lines or with harmless vertical lines caused by aging. Chemotherapy, liver disease, kidney disease, and severe malnourishment can cause Muehrcke’s double white lines.

See an MD if your fingernails are suddenly covered with lines or ridges not caused by injury.

The A6 version of hand, foot, and mouth disease recently resurfaced causing severe rashes and fever. Some children have been hospitalized due to dehydration and pain. Once the rash has disappeared fingernails and toenails may fall off. They will eventually grow back.