A rash is an area (or areas) of reddened or discolored, irritated, bumpy, painful, or swollen skin. Usually, rashes aren't harmful or dangerous.
Many things can cause rashes, including medical conditions, allergies, and infections. Some are caused by bacteria (such as impetigo), viruses (chickenpox, cold sores, and measles), fungi (ringworm), and skin parasites (lice, bedbugs, and scabies). Often, the specific cause is unknown.
Rashes can be dry and scaly, red and itchy, wet and warm, crusty and blistered, or flat and painless. Some rashes form right away and others can take several days to appear.
Treatment, when needed, will depend on the cause of the rash.
For rashes that may be caused by an allergen, such as hives, the doctor will try to find out which food, substance, medicine, or insect caused it so that it can be avoided in the future. Many fungal skin infections (like ringworm and athlete's foot) can be treated with over-the-counter topical antifungal creams and sprays.
Itchiness often can be managed with home care like oatmeal baths, cool compresses, anti-itch creams, or calamine lotion. More severe cases might be treated with an antihistamine (either as a liquid or pill) to decrease itching and redness.
Contact a doctor if the person seems ill, or if the rash is accompanied by fever or lasts more than a week
Keep in Mind
While many rashes can be itchy, try not to scratch. Scratching can make a rash take longer to heal and can lead to infection or scarring.
All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.