What are the causes of vulvar redness and swelling, and how is it treated?

Patient's question:

Age
Detailed medical condition and consultation purpose: My daughter has experienced redness and swelling on both sides of her vulva whenever she urinates frequently, which started about two and a half months after her birth. Now that she is almost three years old, this condition still occurs frequently, especially during the summer. For this, we have visited doctors many times, but each time the diagnosis was inflammation, and the treatment involved a small dose of anti-inflammatory medication and a few anti-inflammatory injections, which only treated the symptoms rather than the root cause. I would like to consult on what might be causing this and how it should be treated.
Current general condition: Frequent urination, redness and swelling of the vulva.

Doctor's answer:

Source: Sina News
Hello, parents should pay more attention to their children's hygiene and cleanliness.
1. Girls should avoid wearing open-bottom pants as much as possible. If the child cannot yet control their bladder, use diapers or pull-ups and change them frequently.
2. After each bowel movement, clean the child promptly to avoid fecal contamination of the external genitalia.
3. Undergarments should be made of pure cotton to prevent allergic irritation of the external genitalia.
4. If the child has pinworms, take deworming medication promptly to prevent itching and redness of the external genitalia caused by the pinworms.
5. For children already infected with inflammation, seek medical attention immediately.
There are special external genital cleaning solutions for girls on the market, and they are quite effective. However, doctors believe that plain water is sufficient for cleaning the external genitalia. What you need to pay attention to are the following points:
· The basin and towels used to clean the child's external genitalia must be dedicated and should not be used for any other purpose.
· The basin is best made of metal so that you can heat the water for washing. Place the towel in the water, heat it to a boil, and then cool it to around 40°C before use. Avoid mixing hot and cold water. This method thoroughly kills bacteria from tap water, towels, and the basin.
· Do not use soap or other products to clean the child's external genitalia, and avoid using water that is too hot.
Source: Sina News