Odd is an informal word to mean occasional or now and again.
– My knee gives me the odd problem, but mostly it’s fine
It is completely different to odd when the meaning is ‘strange’ or ‘unusual’ so it’s really important to understand from the context which ‘odd’ the patient means.
One way to tell it apart is that odd meaning occasional often comes in this structure:
the odd (noun) e.g. pain, problem, difficulty.
Odd when the meaning is strange on the other hand often comes in this structure:
a/an odd (noun) discharge, lump, feeling.