Jared and Terri brought their newborn son to the office two days after he left the nursery for his first check-up. His weight was fine; the breast feeding was going well and there was no jaundice. The next visit was scheduled for one week.
The following day I was surprised to see his name listed under sick visits. The parents looked worried and concerned. “When I undressed him this morning I noticed some pustules on his trunk,” Terri said as she quietly started to weep. Then Jared added, “Last Spring I had an infection with MRSA (Methicillin Resistant Staph Aureus) that I contacted from our 3-year-old. It was awful and hard to get rid of. It’s been months since it resolved. I have been very careful to wash my hands but I’m afraid that the baby now has it!”
The baby had a normal temperature and seemed fine. As mom started to undress him I smiled and told them they did not have a thing to worry about. He had a number of lesions on his trunk that were small, about 2 mm in diameter. They looked like small pustules of white-yellow fluid on a red base. Some were a bit raised while some were flat with no fluid--just red in color. When I told them that he had erythematic toxicum they had an even more pained look on their faces. While it sounded dreadful it was a very benign condition that occurs in almost half of all newborns.
The translation from Latin is “toxic red rash”. However it has nothing to do with an infectious process. Erythema toxicum noenatorum (ETN) presents on about the second or third day of life and can last for a couple of weeks. The rash is like mini-hives in that they come and go almost hourly. A baby can have a number of lesions on the chest in the morning and then they are gone by afternoon. More can appear on the chest that night. They do not bother the baby and no treatment is required.
When it is tested the fluid in the lesions looks like pus but the type of white blood cells in the fluid is eosinophil which is associated with more of an allergic reaction. It is NOT neutrophil which is associated with a bacterial infection. When the fluid is sent for culture, attempting to grow bacteria, the results are always negative. So ETN is a benign newborn condition that may represent an allergic reaction of some sort. The exact cause is not known. We do know, however, that close to 50 percent of all newborns get it.
I thanked Jared and Terri for their heightened level of concern for their baby. I reassured them that this was not at all like the MRSA infection dad had. I reminded Jared that the infection he had was a solitary, large, red boil that was firm, tender and the size of a small grape. It grew over a matter of days. Even with antibiotics and warm compresses it took days before it showed improvement. The MRSA lesion his other son had actually required drainage before it improved. Since those infections were almost six months ago I assured them that it was a resolved issue. Needless to say, the importance of good hand washing for everyone who was going to hold the new baby was still stressed.
They seemed relieved, especially dad who was afraid he might be in the doghouse should the baby have had a staph infection. I received a call the next morning from Terri and she said, “I just wanted to tell you that when I gave the baby a bath last night his skin was perfectly clear. When I changed his diaper at 2 AM he had about ten lesions on his lower abdomen and legs. And this morning the skin is clear again.” She added, “I know this is not dangerous or serious, but I’m sure glad it only lasts two weeks.”
While erythema toxicum is common, benign and self-resolving, ANY newborn that has a suspicious rash should be seen by his or her doctor. He will determine if this is a benign condition or a more serious type of condition that warrants further tests or treatment.