this could be some worm infestation (?pin worm) or perianal dermatitis
that is troubling your daughter.
this perianal dermatitis is caused by many bacteria most commonly streptococcus
and may be candida and other fungal infections.
in my opinion you should consult your pediatrician
as it need to be examined with detailed history for proper treatment.
may be it would require stool examination for ova and cyst
, throat and perianal culture and some other test depending on the clinical examination.
best would be to maintain proper hygiene like, proper hand wash after loo and before meals, keep nails trimmed and clean, use full clothes at night and not to take hands into mouth etc.
hope my answer will guide you in getting a solution
thanks for the query
Dr. Amit Kumar