When it comes to a viral rash in a baby, there are many potential causes.

This article will cover some of the most common causes and when to seek emergency medical attention for a viral rash in a baby.

Causes of rashes in babies can include bacterial, viral, and fungal infections or reactions to medications, soaps, cleaning products, or environmental triggers.

Learn about some common rashes in babies here.

According to the American Family Physician (AFP), viral rashes are usually not as itchy as other rash causes, such as tinea capitis (fungal) or atopic dermatitis (eczema).

Learn more about viral rashes that can affect both adults and children here.

Examples of some viral rashes that can affect babies include:

Fifth disease

Fifth disease is a viral illness that causes a rash. It is also known as erythema infectiosum and ‘slapped cheek disease.’ According to the Centers for Disease Control and Prevention (CDC), parvovirus B19 causes the condition. It can affect adults but is more common in children.

Fifth disease symptoms include:

  • distinct “slapped cheek” rash that causes color changes to a child’s cheeks
  • fever
  • a headache
  • rash that spreads to the arms, back, buttocks, chest, and legs.
  • runny nose

The condition usually causes mild symptoms and lasts anywhere from 7–10 days. Fifth disease rashes may have a “lacy” appearance.

Learn more about fifth disease here.

Measles (rubeola)

Measles is a highly contagious virus that can cause serious complications in babies. Measles symptoms include:

  • a cough
  • a fever that may be higher than 104°F
  • red, blotchy rash that usually starts on the face about 3–5 days after symptoms begin
  • runny nose
  • watery, red eyes

A vaccine is available for the measles virus, but doctors do not usually administer it to those younger than 12 months old. However, if a person is traveling overseas (where fewer people may have received the measles vaccine), a doctor may recommend a baby aged 6–11 months has one dose of the MMR vaccine.

Learn more about measles here.

Roseola

According to AFP, roseola infantum is a viral rash that is common in infants. Some of the key symptoms include:

  • a rash that starts in the trunk and may spread to the legs and arms
  • a high fever that exceeds 102°F may occur before the rash
  • a non-itchy rash
  • small to large slightly raised bumps

A roseola rash can often resemble measles in appearance but does not usually start on the face as a measles rash does. Also, an infant with a roseola rash does not usually appear ill, unlike with measles. A roseola rash usually lasts 1–2 days.

Learn more about roseola rash here.

Rubella

Also known as the German measles, rubella is a viral illness that causes a mild fever (usually less than 101°F) and a rash. Babies also may have the following symptoms:

  • a cough
  • eye redness
  • runny nose

The virus does not usually cause serious symptoms,. However, the CDC indicate that some babies could experience bleeding problems or brain infections, although this is rare.

A vaccine is available for rubella, and doctors usually administer it in combination with the measles and mumps vaccine. It’s known as the MMR vaccine.

Learn more about rubella here.

Chickenpox

The varicella-zoster virus causes chickenpox, a condition that can lead to an itchy, blistery rash. A baby will often experience other symptoms before developing the rash.

Symptoms may include:

  • appetite loss
  • fatigue
  • fever

Chickenpox can have severe side effects in babies, and they are at higher risk for complications. These include pneumonia, other serious infections, and dehydration.

A vaccine is available for chickenpox, but most babies do not receive the shot until they are 12–15 months old.

Learn more about chickenpox in babies here.

The doctor will also ask a parent or caregiver about a baby’s symptoms and use these along with a visual examination to make a diagnosis.

Some questions a doctor may ask include:

  • How long has the baby had the rash?
  • Where did the rash first appear?
  • What have you used to treat the rash?
  • Have other members of the household had a similar rash?

Many viral rashes appear on both sides of the body, often the back, chest, and stomach areas.

While vaccines are available for many of these viruses, doctors do not usually give the shots until babies are about 12 months old or more. As a result, parents and caregivers must protect babies from others who are sick and wash their hands frequently.

There are no cures for viral illnesses. Medications, such as antibiotics, will not treat the virus or make it go away. Treatments involve supporting the baby and include the following:

  • Bathing a child in lukewarm or cool water if they have a fever can help. Use mild soap and avoid rubbing the skin dry.
  • Giving the baby a pain reliever, such as acetaminophen, might help ease symptoms. However, a caregiver may wish to call their child’s pediatrician to determine the appropriate dosage given a baby’s age and weight. A baby or anyone under age 18 should never take aspirin unless directed by their healthcare provider.
  • Encouraging the baby to feed frequently to help prevent dehydration. A caregiver may wish to call their child’s pediatrician to determine if they need oral rehydration solutions.
  • Covering the rash with soft, loose-fitting clothes might help reduce irritation.
  • Encouraging the baby to take frequent naps and engaging in gentle play when the baby is awake can help distract them.

Most viral rashes will go away with supportive treatments at home. However, there are times when a parent or caregiver should seek emergency medical attention. This includes:

  • when a baby is having problems breathing
  • when a baby is breathing much faster than normal
  • when petechiae (small, purple or red dots that indicate bleeding into the skin) or purpura (large, purple or red spots) accompany the rash and do not fade when pressed

Call the baby’s doctor if the baby appears dehydrated (few to no wet diapers over several hours), or their fever exceeds 101.5°F. Their doctor may give the caregiver further instructions, including whether they should come to the doctor’s office.

Viral rashes can be common in babies. Because babies do not typically receive immunizations against many of the conditions that cause the rashes, prevention is the best medicine.

Washing hands frequently, keeping surfaces clean, and keeping a baby away from sick individuals can help.

If a caregiver is worried about a baby’s rash or symptoms, they should contact their child’s pediatrician.