Itching in the ear with liquid discharge can be the following possibility
1. fungal infection- severe itching
with constant discharge.
2. Wax which causes itching or dryness of ear and scaling.
3. Perforation in the ear drum which causes liquid like discharge.
If the ENT Dr's have told that there isnt any particular cause that they can determine then there isnt anything to be worried about. If the ear drum and canal is normal then you can use dewax drops once a week to reduce itching in the ear.
I hope you found my response to be helpful and informative. If you have any additional concerns I would be happy to address them.