What is erythema toxicum neonatorum?

Erythema toxicum neonatorum (ETN) is often shortened to erythema toxicum, and is also known as baby acne or toxic erythema of the newborn. ETN is a common harmless skin rash that affects healthy newborn babies.

What do the words erythema toxicum neonatorum mean?

Erythema is the medical word for redness. Neonatorum refers to the fact that the rash occurs in the neonatal period. The neonatal period is the time between birth and 28 days of age. A baby in this age range is called a neonate.

The name ETN is confusing because the condition is not toxic. It is also not the same as the acne that affects young people and adults. (See separate leaflet called 'Acne' for more information.)

What causes erythema toxicum neonatorum?

The exact cause is unknown. It is not due to an infection, even though pustules (pus-filled spots) are often present.

Various ideas have been suggested, including the possibility that it is a normal inflammatory or immune system response in babies. It has not been proven to be an allergic problem. It is also not related to whether the baby is breast-fed or formula-fed.

How common is erythema toxicum neonatorum?

ETN is very common. Between 3 and 7 in every 10 babies develop it. It seems to be more common in babies born at full term (between 37 and 40 weeks' gestation) compared with premature babies.

Which babies get erythema toxicum neonatorum?

On average, ETN occurs in healthy babies born at full term, between 3 and 14 days of age. The rash can occur in the first 48 hours of life, but 9 out of 10 cases are in babies more than 2 days old.

Overall, it seems to be more common in male babies (about half of male babies get it) compared with female babies (about a third of female babies get it). However, it is more common in baby girls if it is a woman's first pregnancy.

What does the rash of erythema toxicum neonatorum look like?

The rash of ETN generally looks like red blotches, predominantly affecting the face and trunk (body). It does occur on the arms and legs too (but is rare on the palms or the soles).

Little raised spots called papules are common. Sometimes there will be little pustules (pus-filled spots) or vesicles (fluid-filled small blisters). There may be many spots or very few. The different spots vary in size. The spots blanch with light pressure. This means that they become pale and fade when pressed. The rash can be very transient (temporary) and sometimes individual spots can disappear within hours.

The baby appears well and the rash does not seem to cause any bother.

Note: if there is any doubt as to the cause of a skin rash in any baby or child, it is essential that you seek medical advice and a firm diagnosis. This is especially important if your baby seems unwell in any way (for example, if your baby has a temperature, is not feeding, is lethargic or inconsolable and not the same as normal). Other rashes can occur in babies and may be the sign of serious illness.

Are any tests needed to diagnose erythema toxicum neonatorum?

No tests are needed to diagnose ETN. The rash is generally easily recognisable by doctors and midwives. Tests may be needed if there is any uncertainty as to the cause of the rash, particularly if your baby is unwell.

What is the treatment for erythema toxicum neonatorum?

There is no specific treatment for ETN. The rash settles completely without any treatment.

What should I do?

If your baby develops ETN, there is no need to worry. Your baby will not be in any discomfort or have any distress related to the rash. The skin may look red and angry (and your baby may look less than perfect temporarily), but do your best to ignore it.

Avoid over-washing your baby - babies have delicate skin that can dry out easily with detergents. Resist any temptation to pick, squeeze or burst any pustules - as this would make a skin infection more likely to occur. Creams and lotions are not required for the rash. If you are already using products to wash and moisturise your baby it is fine to continue them, but ensure they are fragrance-free and designed for use in babies.

How long does erythema toxicum neonatorum last for?

Typically, the rash lasts for a few days only. In almost all cases it has completely gone within 2 weeks. Very occasionally the rash can recur. This can happen up to 6 weeks of age. Usually recurrences are mild.

Are there any long-term effects?

There are no long-term problems associated with ETN. The rash settles spontaneously, leaving normal skin. Of course, some babies develop dry skin, eczema or other skin problems, but these are not related to ETN.

References

• Yan A C; Erythema Toxicum, eMedicine, Aug 2009
• Beute TC et al; Erythema Toxicum Neonatorum, eMedicine, Jun 2009