I have bumps across my buttocks. They don't come to a head and they're *not* excessively itchy.
They do, however, seem to swell/spread when scratched or "popped."
I had a skin test done, where a swab was sent off to a lab to see if it'd produce anything on a petri, and it came back negative.
I took antibiotics for them for a while, to no avail, tried diaper rash (??) ointment for a while, etc.