Worried about skin itching

I have been suffering from itchy skin for several years.

The allergy test at the dermatology clinic came back normal, and the blood toxin levels were also normal, so the cause could not be identified.

The pills and ointments I was given were only temporary, and there was no meaning of a complete cure. Every year, I suffer from itching intermittently, which is very distressing.

It's not effective either. Right now, I'm just enduring with ointments instead of going to the hospital. I wonder why this trouble is happening, something I've never experienced before, and it makes me sad. These days, my head and around my ears are itchy, and I want to know the cause and treatment methods.