Allergens, infections, sunburn, stress and autoimmune disorders may cause a buttock rash, states Healthgrades. Medications, diapers in babies, and severe heat or cold may also result in a buttock rash.
The skin may react against industrial chemicals such as latex, cosmetic dyes or detergents, toxic substances, and metallic substances, including copper, according to Healthgrades. Eczema, an allergic reaction to insect bites such as a bee sting, or reactions against certain foods may lead to a rash. Allergic purpura and anaphylaxis are life-threatening allergic reactions that may cause a buttock rash. A person with rashes due to these severe conditions should seek immediate medical attention.
Yeast, scabies, strep throat, ringworm, Rocky Mountain spotted fever and scarlet fevers are examples of infections that may bring about a rash, notes Healthgrades. Other infectious causes include chickenpox, shingles, meningitis, impetigo and Lyme disease. Pityriasis rosea, measles, mumps and rubella may also trigger a rash.
Autoimmune disorders capable of producing a buttock rash include rheumatoid arthritis, psoriasis and Kawasaki disease, a rare disease with symptoms such as high fever, inflammation of blood vessels and variation in mucous membranes, explains Healthgrades. Systemic lupus erythematosus, a condition where the body damages its own healthy cells, may also result in a buttock rash.