There are several reasons you might get a rash on your butt, including tiny red bumps or dots on the buttocks; blisters in the anal area; itching that gets . skin that is thin and wrinkled or easy to tear; bleeding and blistering.
Ringworm: More commonly known as jock itch, ringworm is a fungal infection that causes a red, ring-shaped rash in the groin and butt area.
Folliculitis looks just like butt acne. When hair follicles get damaged, they let in bacteria and get infected. This produces a rash of small red.
This is especially true if you have bumps and blemishes on your butt, since these pimply Normal: A Red Rash After Using Cleansing Wipes.