All About Erythema Toxicum Neonatorum

Medically Reviewed by Stephanie S. Gardner, MD on May 02, 2024
5 min read

Erythema toxicum neonatorum (ETN), sometimes just called erythema toxicum, is a painless skin condition that affects newborn babies. It’s not dangerous to you or the infant. 

ETN causes red patches on the baby’s skin. It may look like pimples on the infant’s chest, face, arms, and legs.

It looks similar to acne, but it’s not the same as baby acne. ETN doesn’t last as long as baby acne. It clears up on its own within a week or so.

About half of all infants develop ETN, so it’s quite common. The condition is more common in some babies compared to others, such as infants who are born at full-term compared to premature babies.

It’s not clear why babies get ETN. Some experts think it happens because the pores around a hair, or follicle, as well as their oil glands aren’t fully developed. Others say it happens because of inflammation and bacteria around the pores. 

A few risk factors for developing ETN include being born vaginally, having a long delivery, being male or assigned male at birth, being born at term, or being born in a hot, wet climate. A diet with powdered milk substitutes and high birth weight are other risk factors.

When a baby has ETN, they will have small, fluid-filled bumps on their skin. The bumps may show up on their face, chest, or arms and legs – it’s never on their feet or palms – anywhere the baby has hair-related pores. It may look like the bumps are filled with pus, but it’s not an infection. 

The bumps may look like the baby has been bitten by fleas. They may be set apart or grouped in clusters.

Symptoms of ETN can appear at birth, or you may see the condition start a few days after the baby is born. It most often shows up on the second or third day of a child’s life.

Bumps may go away and reappear in new areas in a few hours. If you gently press on them, they may get paler in color. In babies with lighter skin tones, the bumps may have a red patch around them. On darker skin tones, the bumps can look brown, purple, or gray. 

Your pediatrician or midwife can tell if the baby has ETN just by looking at it. They may take a sample from the fluid in one of the bumps to see if it contains any viruses, fungi, or bacteria that could indicate something more serious.

If the parent has genital herpes and the baby was delivered vaginally, the doctor may remove the bump with a scalpel, or sharp tool. Then, the health care provider will look at the sample under a microscope to see if it contains herpes.

Once you know that your baby has ETN, you don’t have to treat it because there’s no medical treatment for ETN. It goes away on its own. 

The rash and bumps usually go away within 5 to 14 days. They may come back in a few weeks and vanish again. In rare cases, it can pop up within the first month. 

The best way to let it clear up is not to touch or pick at the bumps. Doing that could cause an infection.

Take care of the baby’s skin as you would do otherwise. That means giving the baby a sponge bath until the umbilical cord falls off in 1 to 4 weeks. Wait until the cord falls off and the baby is a week or older to give the baby a bath. When you do give your baby a bath, use warm water and a mild, unscented cleanser. 

Typically, ETN goes away on its own and your baby will be fine.

If you pick at the rash, that could cause an infection. Researchers have found a link between ETN and eosinophilic esophagitis – a type of inflammation in the pipe that connects your mouth to your stomach. If your child ever has irritation in the esophagus, make sure you remind the doctor about their ETN rash as a baby.

If the bumps seem to be getting worse and they’re not gone by the time your baby is about 2 weeks old, call the doctor.

You should also call the pediatrician if your baby:

  • Isn’t feeding like normal
  • Develops a new rash
  • Has a fever of 100.4 F or higher when you take the temperature rectally (through their anal opening)
  • Is fussy, floppy, or very drowsy

Erythema toxicum neonatorum or ETN may look like acne on your baby, but it’s not the same thing as baby acne. This painless condition can come and go in the first two or so weeks of life but will eventually clear up on its own. 

ETN may appear reddish on light skin tones and gray, purple, or brown on darker skin.

Once you confirm that the rash or bumps are ETN, just care for your baby’s skin as usual. No medical treatment for the condition exists because the bumps go away without doing anything.

How do you treat erythema toxicum neonatorum?

You don’t treat ETN. The rash goes away on its own within a week or so.

How long does it last?

Spots can emerge and go away within a few hours. Overall, it should clear up within 2 weeks.

What is a differential diagnosis of erythema toxicum neonatorum?

Conditions that may have similar symptoms include herpes simplex, candida, and staph infections, as well as milia, baby acne, miliaria, and transient neonatal pustular melanosis (TNPM). Infections, congenital disorders, and other diseases can also cause rashes.

How do you treat neonatal rash? 

Find out what the rash is to see if it needs to be treated or if you can treat it. ETN doesn’t require a specific treatment. However, if you have concerns about your newborn's skin or if the rash seems severe or is accompanied by other symptoms, you can consult a pediatrician or a dermatologist.