What causes ridges in the nails?

Trauma or illness: If only one nail is involved it could be due to trauma from approximately 4-6 months ago. The nail is made in the nail matrix which is right beneath the cuticle. Thus, it is easy to injure this area. However, if all nails are involved look back 4-6 months ago...Did you have a high fever or surgery? Stresses such as these can give ridges in multiple nails. See your doctor for further eval.

Vertical nail ridges: are often caused by aging. Other causes include anemia, splinter hemorrhages, or conditions like rheumatoid arthritis, trachyonchia or peripheral vascular disease. Horizontal nail ridges (or Beau’s lines)run across nail & might be signs of diabetes, thyroid disease, kidney disease. They may occur in people who had syphilis or muscles or who had chemotherapy. These should be evaluated.