you can see this eruption. i cannot so seeing your dermatologist is the appropriate next step. a description is really not sufficient to make an accurate dermatological diagnosis let alone rule out such obscure things as skin cancer. there can be hundreds of reasons. incidentally it would be highly unusual to have cancer in this area so don't worry too much. just have your dermatologist make this important call.
red rash on buttocks. 40 yr old w/m. 6 mths ago i noticed a small "rash" on my upper buttocks above the crack. its red bumps clustered in about a 2x2 inch area. they dont hurt leak or itch. if i didn't happen to touch them i wouldnt know they were there. i have googled over past 2 days an i come up with everything from eczema to shingles to cancer etc. ideas? i started using hydrocortisone yesterday but i will make appt to see my derm. thanks for advice insight an please rule out anything you see fit like cancer etc.