Erythema toxicum neonatorum (ETN) is a common skin rash affecting healthy newborn babies. It is not serious, does not cause the baby any harm and clears up without any treatment. It is sometimes known as erythema toxicum, baby acne or toxic erythema of the newborn.
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 erythema toxicum neonatorum is confusing because the condition is not toxic. It is also not the same as the acne that affects young people and adults.
What causes erythema toxicum neonatorum?
The exact cause is unknown. It is not due to an infection, even though pus-filled spots (pustules) are often present.
Various ideas have been suggested, including the possibility that it is a normal effect of a baby's immune system. It is not an allergic problem. It is also not related to whether the baby is breast-fed or bottle-fed.
How common is erythema toxicum neonatorum?
ETN is very common. Up to 4 or 5 in every 10 babies develop it. It seems to be more common in babies born at full term (between 37 and 40 weeks of 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 babies who are heavier at birth, in babies born in the summer or autumn and in babies who are fed milk powder substitute or a mixed diet.
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What does the rash of erythema toxicum neonatorum look like?
The rash of ETN generally looks like red blotches, mainly affecting the face and body (trunk). 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 pus-filled spots (pustules) or fluid-filled small blisters (vesicles). 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 temporary (very transient) and sometimes individual spots can disappear within hours while new ones will appear somewhere else.
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 (fever), is not feeding, is lacking in energy (lethargic) or is 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?
Usually, 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 needed 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 the baby - babies have delicate skin that can dry out easily with detergents. Resist any temptation to pick, squeeze or burst any pus-filled spots (pustules). 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 two weeks. Very occasionally the rash can return (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.
Further reading and references
Monteagudo B, Labandeira J, Cabanillas M, et al; Prospective study of erythema toxicum neonatorum: epidemiology and predisposing factors. Pediatr Dermatol. 2012 Mar-Apr29(2):166-8. doi: 10.1111/j.1525-1470.2011.01536.x. Epub 2011 Nov 8.
Toxic erythema of the newborn; DermNet NZ
Mahajan VK, Sharma NL; Erythema toxicum neonatorum. Indian Pediatr. 2010 Sep47(9):793.
Liu C, Feng J, Qu R, et al; Epidemiologic study of the predisposing factors in erythema toxicum neonatorum. Dermatology. 2005210(4):269-72.