Brittle Nails, Ridging, and Pitting
Changes in the texture of the nails often accompany changes in the color and shape of the nails and may reflect the additional side effects of a fungal infection, systemic condition, or poor nutrition.Common changes in texture include brittleness, pitting, and ridging.
Brittleness can become so severe that nails chip, crack, break off, or loosen from the nail bed. "Pitting" refers to the appearance of tiny pits in the nail: it is most commonly caused by psoriatic arthritis. There is no treatment for pitting.
Ridges in the nail are often caused by trauma, but can develop after serious illness. They represent a temporary interruption in the normal nail growth. Changes in the texture of the nails can be treated with topical medications, but first the systemic cause of the changes should be identified and treated by a physician.
Reference: Great Feet For Life: Paul Langer DPM