sometimes accompanied by muscle aches in the buttocks. The rash itself may include painful, fluid-filled blisters. Heat rash, or miliaria, develops when your sweat glands and ducts become clogged.

Medically reviewed by Susan Bard, MDMedically reviewed by Susan Bard, MD Buttock rashes can develop from heat, allergies ...

Using mild cleansers, wearing soft fabrics and managing stress can also reduce flare-ups. Heat rash occurs when sweat becomes trapped under the skin, leading to irritation and tiny, itchy bumps.