Hello,
It can be due to leuconychia. It is a medical term for white discoloration appearing on nails. Causes of leuconychia are trauma to the nail, zinc deficiency, hypoalbuminaemia (low albumin), which is caused by the nephrotic syndrome (a form of kidney failure), liver failure, protein malabsorption and protein-losing enteropathies. My sincere advice is to consult a physician and get all these possibilities evaluated.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.