• Topic Overview
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Topic Overview

Healthy skin is a barrier between the inside of the body and the outside environment. A rash means some change has affected the skin. A rash is generally a minor problem or is part of an illness that will go away on its own. A rash may be caused by contact with a substance outside the body, such as poison ivy (contact dermatitis), or by other more serious illnesses, such as measles or scarlet fever (strep throat with rash).

Generalized rashes over the whole body that are caused by viruses are more common in babies and young children than in adults. A rash may be caused by a viral illness if the child also has a cold, a cough, or diarrhea, or is in a day care setting where he or she is with other children with viral illnesses. Most rashes caused by viruses are not serious and usually go away over a few days to a week. Home treatment is often all that is needed to treat these rashes.

After a child has had a rash caused by a virus, his or her body generally builds an immunity to that virus. This immunity protects the child from getting that specific viral illness and rash again. Common rashes caused by viruses include:

• Chickenpox (varicella). This rash is a common, contagious illness caused by a type of herpes virus.
• Fifth disease. This facial rash looks like the cheeks have been slapped. It also causes a lacy, pink rash on the arms and legs, torso, and buttocks.
• Roseola (roseola infantum). This rash occurs about 3 days after a high fever.
• Unknown virus. Sometimes the specific virus that causes a rash is never known.

Localized rashes which affect one area of the body have many different causes and may go away with home treatment. Common localized rashes that occur during childhood include:

• Diaper rash. This rash is caused by rubbing, moisture, chemicals, or bacteria in the baby's urine or stool; substances in disposable diapers; or soaps used to wash cloth diapers.
• Impetigo. This bacterial skin infection is caused by strep or staph bacteria.
• Heat rash (prickly heat). This rash often results from a well-meaning parent dressing his or her baby too warmly, but it can happen to any baby in very hot weather.
• Cold sores. These are sometimes called fever blisters. Cold sores are clusters of small blisters on the lip and outer edge of the mouth caused by the herpes simplex virus.
• Contact dermatitis. This rash is caused by contact with a substance, such as food, soap, or lotion, that causes an allergic reaction. Most contact dermatitis is mild and goes away when your child's skin no longer comes in contact with the substance.
• Cradle cap. Cradle cap is an oily, yellow scaling or crusting on a baby's scalp. It is common in babies and is easily treated. Cradle cap is not a part of any illness and does not imply that a baby is not being well cared for.

A very rare and serious type of generalized red rash is toxic epidermal necrolysis (TEN). This may cause the skin to peel away, leaving large areas of tissue that weep or ooze fluid like a severe burn. If this type of rash occurs, a visit to a doctor is needed. TEN may occur after the use of some medicines.

To know how serious the rash is, other symptoms that occur with the rash must be evaluated. Check your child's symptoms to decide if and when your child should see a doctor.