Genital Ulcer

History:

An 11 8/12 year-old girl presents to a paediatric emergency room reporting acute pain (vulvodynia) and ulcerations to the genitalia since 4 days. It was preceded by a Covid-19 infection with symptoms lasting for 3 Days. Because of increasing pain she presented to her paediatrician who treated her with antibiotics (Co-Amoxicillin 625mg 3x/d), but there was no improvement.

She has no relevant medical history, no recurrent buccal or genital apotheosis, no abdominal pain, stool history is unremarkable.
She did not receive any regular medication, vaccination according to CH-schedule.
Menstruation started one month before.
She was sexually inactive, and did not apply any cream or anything else to the vulva.
There was no history of trauma or sexual abuse.
This is the first time she had experienced such symptoms.

Physical Examination:

Slightly reduced general condition for pain.
Vital signs within normal range

Labia major: redness and swelling, 2 round crusted skin lesions about 1.5 cm on both sides symmetrical.
small lymph nodes were palpated in inguinal area.
Labia minor is not involved
No abnormal leucorrhoe
No signs of trauma