It's hard to say without seeing it, but you are either dealing with a fungal/yeast infection (eg, tinea corporis
, or candida), or a bacterial skin infection
caused by staph bacteria.
Both tend to itch at first, but can also become painful. Yeast and Fungi do happen a lot on children and especially in the buttock region (just like diaper rash
). The more concerning bacterial infection (staphylococcus
) will usually spread very fast and if the skin breaks down, it will form a "honey crusting" type of appearance.
The swollen ring you described and spreading by small "satellite lesions" makes me think this is a fungal or yeast infection. You can try ketoconazole
cream on the area to see if it controlls it. Otherwise, I would recommend getting it examined by a doctor for proper treatment.