Split fingernails and other nail issues are usually treated by dermatologists. A dermatologist is a doctor specializing in the treatment of skin, hair and nails.
As with most medical conditions, a patient should consult with her general physician about split fingernails. The GP may recommend treatment by a specialist for specific cases, depending on the severity and patient need. According to the Mayo Clinic, the best treatment for split fingernails is prevention, which includes good hygiene, avoidance of harsh chemicals and keeping the nails dry. Additionally, nail-hardening chemicals and nutritional supplements may help people who are prone to split nails.