Upward-curving fingernails can have various causes, just like most other symptoms. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose upward-curving fingernails, we could:
Do your fingernails curve upwards like little spoons?
Possible responses:→ Don't know
→ A little