I have a client who has a split in her thumbnail that starts at the cuticle and runs halfway down the nail. It is deep, but not bleeding. She says she didn’t hit it or slam it in a door. What would cause this condition, and what can we do to help it heal?

A split in the nail could be due to a space-occupying lesion (a tumor or growth) or scar and should be evaluated by a dermatologist. Depending on the appearance of the split and the size of it, it may require a biopsy to determine what the cause is. This is especially true if there is no history of an injury, as you mentioned. Therefore, in order for it to heal, a definite diagnosis must be made.--Richard K. Scher, M.D.