Autoimmune disorders, allergens, stress and infections can cause a buttock rash, states Healthgrades. Other causes of buttock rash include sunburn, medications, severe cold or heat, and diaper rash in babies. A person suffering from this condition should immediately consult a doctor.
Allergic reactions to industrial chemicals, detergents, cosmetics and dyes can cause buttock rash, notes Healthgrades. Other allergic reactions that lead to the rash may result from contact with metallic substances such as copper and the use of certain soaps, gels or waxes. Insect bites, eczema or atopic dermatitis may also bring about the rash. Rarely, a buttock rash may be caused by life-threatening conditions such as anaphylaxis and allergic purpura.
Infectious causes of buttock rash include ringworm, scabies, chickenpox, yeast and meningitis, explains Healthgrades. Other infectious causes of the rash include a bacterial throat infection, measles, impetigo, Lyme disease, and certain fevers, such as Rocky Mountain spotted fever or scarlet fever.
Rheumatoid arthritis, psoriasis and Kawasaki disease are autoimmune disorders that can cause buttock rash, according to Healthgrades. Symptoms of Kawasaki disease include mucous membrane variations, rash, high fever and inflammation of blood vessels. Systemic lupus erythematosus, which is as a result of the body attacking its own cells healthy cells and tissues, may also cause a buttock rash.