Thank you for your query,
The lesions are looking like some fungal or allergic skin bumps.
But some times worm infestation especially pin worm will cause itching around the anus and in perineal area by laying eggs and causing dermatitis.
If it is due to fungal infection
, local antifungal
cream will be sufficient.
Stool should be examined for ova and cyst to look for worm infestation.
Deworming medication can be given, if not treated previously after consulting your Doctor.
If there is severe itching
, oral antihhistamine like hydroxyzine can be given in prescribed dose.
Consult the pediatrician
for the examination of bumps and to assess the need for topical antifungal
Hope I have answered your query.