Hypothyroidism: An underactive thyroid gland can cause changes in the nails, including ridging. Iron deficiency: A lack of iron in the body can cause ridges to form on the nails, as well as other ...

Longitudinal ridging, which is clinically known as onychorrhexis, occurs on the nails and may appear as vertical striations or lines that originate from the base of the fingernail and continue to ...

Longitudinal ridging on fingernails or toenails ... People often look to their nails for clues about iron, zinc, or vitamin levels, hoping that physical changes might provide an early warning ...