A rash is a common skin condition. It is common for rashes to last for a short time and to disappear without treatment. It is possible, however, for a rash to be a sign of something more serious. Rashes can also be caused by allergic reactions, infections, autoimmune conditions, and more. When rash occurs along with trouble breathing, fever, lightheadedness, or nausea, it is an emergency. Rash treatment is available at Immediate Care of Oklahoma.