Itching at the junction of the penis and scrotum for over a year.

Patient's question:

Itching at the junction of the penis and scrotum for over a year, starting around 1 cm and now about 4 cm, very itchy with scaling. There is also persistent residue in the foreskin that cannot be washed away. What is the cause and how should it be treated?
Additional tests: Used Jieryin liquid and Daktarin, which relieved the itching but had no therapeutic effect.
Medical history: No history of this condition before.

Doctor's answer:

Hello, you might have vulvar eczema. It is recommended that you visit a dermatology department in the hospital to get checked and identify the cause, and actively treat it.