Hives

Small red welts or swellings of the skin that are itchy and move around to different areas of the body over a period of minutes or hours could be hives (also called urticaria). This type of rash can be an allergic reaction to eating certain foods or coming in contact with possible environmental allergens such as dogs, cats or grass. Hives may also develop while a child has a viral illness, such as a cold or upper respiratory infection.

Most hives can be successfully treated at home and don’t require a trip to the doctor. However, there are a few exceptions.

“Usually you can treat the rash’s itchy symptoms and swellings with over-the-counter antihistamine medications such as diphenhydramine (Benadryl) or cetirizine (Zyrtec),” Dr. Gilliam says. “But if your child has any facial or lip swelling associated with the hives or is having difficulty breathing, seek urgent medical attention.”

Contact Allergy Rashes

Similar to hives, contact allergy rashes occur when the skin is irritated by a substance it comes in contact with. Frequently, this is a chemical in a product applied to the skin, such as sunscreen, or a natural chemical in a plant, such as poison oak resin. The rash appears where the product was applied or the plant brushed against the skin.

Contact allergy rashes are bumpy and pink, sometimes flaky and often very itchy. The first step in treating them is to look for possible causes. If it was a product that you think caused the allergy, stop using it. If you were hiking, it may be a reaction to poison oak.

The rash will typically go away by itself, but you can ease discomfort and speed healing by applying an over-the-counter ointment that contains 1 percent hydrocortisone to the affected skin. Mild moisturizers such as Aquaphor and Vaseline can also be soothing.

“If the rash starts spreading, becomes very uncomfortable, or the skin becomes open and raw and could get infected, contact your child’s doctor as your child may need stronger medications,” Dr. Gilliam says.

Bacterial Rashes

A common bacterial infection that causes a rash is impetigo. Also known as a staph infection, impetigo causes the infected area of the skin to look very red. Sometimes the skin may also be raw and crusty.

“One of the most common locations for impetigo is around the nose,” Dr. Gilliam says. “If your child is infected, you can first try an over-the-counter topical antibiotic ointment such as Bacitracin, Neosporin or a triple antibiotic product. If the rash spreads to other areas of the body and your child has a fever, take your child to the doctor.”

Rashes as a Medication Side Effect

Sometimes, a rash can be caused by an allergic reaction to a medication, such as an antibiotic. If your child develops a rash while taking antibiotics, you should take your child to the doctor, Dr. Gilliam explains.

A rash caused by an allergic reaction to the medication usually consists of small red bumps that cover the whole body,” Dr. Gilliam says. “Don’t delay seeking medical attention if the rash is on the lips or eyes and/or the skin looks cracked, raw or is bleeding.”

Rashes Due to Viral Infections

There are many contagious viral infections that can cause a rash. These include fifth disease, also known as the “slapped-cheek rash,” and hand, foot and mouth disease. More serious diseases (such as measles) also manifest with a rash.

Since rashes caused by a viral illness are contagious, it is a good idea to isolate a child with such a rash. Most childcare centers and schools will send children with rashes home and ask that they not return until the rash has either cleared up or been checked out by a doctor.

“If your child has a mild rash with a viral illness and doesn’t have a high fever, watch him or her at home for a few days to see if the rash goes away by itself,” Dr. Gilliam says. “If the rash is itchy or uncomfortable, use over-the-counter antihistamines or 1 percent hydrocortisone cream to help calm the skin.”

If your child has a rash and a high fever, especially if the fever has lasted for a day or two, call your child’s doctor for advice. Some conditions that have rash as a symptom can be very contagious. You may be asked to follow special steps when coming in for your appointment to avoid exposing other people to the suspected condition.

One other type of rash that is caused by a common virus is called molluscum contagiosum. This viral skin infection is harmless, but it can take months and sometimes even years for it to go away. Moslluscum contagiosum often affects young children, but adults can get it, too. The rash consists of small, individual, flesh-colored bumps that often have a central dimple. These bumps can appear anywhere on the body but are found especially where the skin is dry or where a child might have eczema. Most people get between 10 and 20 bumps on the skin and can pass the infection to others as long as the bumps are visible through either direct skin-to-skin contact or by sharing towels and clothing.

“If molluscum contagiosum lasts longer than a few weeks and doesn’t seem to be going away on its own, it’s a good idea to go to the doctor to make sure this is the correct diagnosis and find out about possible treatment options,” Dr. Gilliam says.