I have horizontal nail ridges on thumb and little finger for 6 months now. is it due to hormonal imbalance, nerve damage, or anemia?

Beau's Lines: The indentations can appear when growth at the area under the cuticle is interrupted by injury or severe illness. Conditions associated with beau's lines include uncontrolled diabetes and peripheral vascular disease, as well as illnesses associated with a high fever, such as scarlet fever, measles, mumps and pneumonia. Beau's lines can also also be a sign of zinc deficiency.

Don't know: 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.