What Does Red Blotches On Buttocks Imply?

My 9 month old has red blotches on butt, they are spread out randomly and are only on her butt cheeks, not her back or anywhere else. I don't know if it could just be a rash, but it does not look like a regular rash, so am worried it could be a reaction to something else. I am breastfeeding her and have not added or changed anything in my diet, so don't think it is a food allergy, but not positive. She doesn't seem to be bothered by it, but it's hard to tell with her because she never fusses or complains-even when teething. What could they be?