Redness inside the foreskin could be caused by what illness

Patient's question:

What are the possible diseases that can cause redness inside the foreskin? It's just redness, with no other symptoms
If you go to the hospital, should you go to the dermatology department or the urology and reproductive department?
Follow-up question: The inside of the foreskin is red
It wasn't red before, after all

Doctor's answer:

Hello, the common causes of balanitis include unclean sexual life, phimosis, invasion of pathogenic microorganisms, and poor local hygiene, etc. It is recommended to pay attention to personal hygiene, especially local cleanliness, maintain a regular lifestyle, eat a light diet, drink more water, and avoid spicy and irritating foods.
Suggestions: It is recommended to seek medical attention at a formal hospital for related examinations such as external genital secretion tests and bacterial culture to identify the cause and provide symptomatic treatment.