What are some of the most common skin rashes?

Common skin rashes include seborrheic dermatitis, eczema and poison ivy, according to MedicineNet. Seborrheic dermatitis, the most common adult rash, typically appears as a red, scaly rash on the scalp, forehead, outer ears, cheeks and eyebrows. Eczema frequently appears in children and in hay fever and asthma patients.

Known as atopic dermatitis, eczema is a weeping, itchy, red rash that often develops behind the knees, inside the elbows and on the wrists, ankles and cheeks, notes MedicineNet. Poison ivy is a type of contact dermatitis, a rash that occurs after the skin makes contact with a particular irritant or with a chemical to which an individual is allergic. The parts of the skin that touch the irritant or chemical develop the oozy, weepy rash.