Parts affected A rash is a swelling of the skin that can affect any part of the body. The body part that shows a rash is directly related to its cause. A rash may be accompanied by redness, itchiness, blistering, or crustiness. Some skin inflammation starts as a rash and progresses through stages. There are many different conditions and diseases associated with rashes, from very mild to fairly serious.
Rashes are most common in newborns, infants, and children.
Although they may appear to be serious, most are not and disappear in later childhood. Rashes in adults are often due to allergic contact dermatitis . This is a reaction to metals, dyes, cosmetics, detergents, latex, plant oils, wool, insect stings or bites , and other substances that come in contact with the skin . A more serious skin condition that may be mistaken for a simple rash in early stages is impetigo caused by bacteria. Often the characteristic symptom of a disease is the kind of rash that appears.