As many as 8 percent of the patients visiting emergency departments in the U.S. are there for treatment of skin rashes, also called erythema. Most rashes, however, aren't life-threatening emergencies and can be treated at home, with a primary care physician or dermatologist, or, if needed, in an urgent care center [source: Murray]. If you have contact dermatitis from touching something like poison ivy or poison sumac, you'll want to rinse with water as quickly as possible. Additional treatment for rashes (including contact dermatitis) may include the use of calamine lotion, zinc oxide or an antihistamine.
Here's a quick, although not completely foolproof, way to evaluate your rash at home: If a red rash turns white when touched, such as in the case of contact dermatitis, heat rash and hives, it's probably not a medical emergency. Minor rashes often can be relieved with antihistamines and anti-itch creams. Some rashes, although rare, do need emergency medical attention and may be fatal without immediate treatment. Any rash that spreads rapidly, spreads across an area larger than your hand, blisters, swells or is accompanied by a fever needs immediate evaluation by a doctor.