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Pearls for pediatric dermatology

In his role as Chief of the Section of Pediatric Dermatology at the Children’ s Hospital of

Philadelphia, Dr. Albert C. Yan and his team have seen a wide array of unusual dermatologic cases that have taught him important lessons. He shared 10 (plus one extra) of these

cases and pearls with his Canadian colleagues at Paediatric Dermatology Update in Toronto.

The first five pearls were published in the April/May issue of The Chronicle of Skin & Allergy; following are additional insights of Dr. Yan on some of the dermatologic conditions unique to, or which present differently in, the very young.

Congenital midline lesions

When a child has a lesion on the midline of the head that has been present from birth, the child should be investigated and evaluated for underlying neurological abnormalities, said Dr. Yan.

He provided the example of a case of a severe variant of aplasia cutis congenita found on the midline of an infant’s head. There was a membrane over the lesion, surrounded by hair.

“This is a more subtle variant [of aplasia cutis] that has been called hair collar sign. It has that thick, luxurious hair around a kind of thinner, circular membrane. And often times you’ll see this kind of faint erythema around it.”

“These midline lesions are important to recognize because, when they are present right from birth and you see them on the midline, they represent a region of embryological malformation.” Imaging revealed that this lesion was actually heterotrophic brain tissue exposed through a gap in the skull.

Blame it on a virus

There are several signs that could suggest to a dermatologist that a mystery rash may be viral in origin, said Dr. Yan. “They’re often clustered in communities, they often occur only once and the patient doesn’t get it again, we can’t find any other causes for them, and they spontaneously resolve.”

Some mysteries may not be solved, he added, citing a case where a five-month-old, otherwise healthy child was developing a widespread rash when—and only when—he fell asleep. The child’ s mother even brought Dr. Yan a cell phone camera video of the rash developing in real

time. “As soon as you wake him up, it disappears,” said Dr. Yan. “It had been going on for about three weeks, every time he went to bed, whether it was a nap or his regular bedtime.”

Unable to determine the cause for three weeks, Dr. Yan referred the patient to a neurologist to rule out a dysautonomic condition. While waiting for that appointment, the rash resolved and never reccured.

If it is decided a virus is the cause of a rash, it may not be worth the effort to identify the specific pathogen, he added. “If we don’t know what causes [the rash], or we do but there are a number of different [potential causes] but we’re not sure which one it is at this time, is it worth finding out which virus it is, if there are five or six different ones associated with [the exanthem pattern]?”

Signs of an ‘outside job’

Artificial-looking lesions are often just that: signs of an outside, nonbiological cause, said Dr.

Yan. “Unusual patterns or geometric, or linear, non-anatomic lines indicate an outside job.”

This is particularly common in teens and pre-teens who deliberately challenge each other in

various ways. He showed a series of images of lesions—partial- thickness burns, many of which were perfect rectangles on the forearm. Most of the images had been taken from social

media, and showed “an atypical frostbite reaction,” said Dr. Yan. “This is the salt-ice challenge. The kids do it as a kind of test of willpower. They layer salt on their skin, either on their hands or their forearms or their back. Then they have somebody put ice on top. It allows for the ice to stay frozen, longer, instead of melting away and warming up so they get a frostbite reaction.”

This salt-ice challenge is just one example of deliberately inflicted skin injuries, said Dr. Yan, so it is important to be aware of the sort of artificial, unnatural shaped lesions that point to an outside cause.

Old diseases returning

It is worthwhile to be familiar with historical diseases, because while they have become thankfully rare in the modern world, they can still appear and dermatologists need to

be able to recognize them, said Dr. Yan.

Several patients have presented at the Children’ s Hospital of Philadelphia with a lacy, peeling paint rash and failure to thrive, with the parents suspecting a reaction to something in their diet. Diet was the problem, Dr. Yan related, but not how the parents thought. “I think we’ve

seen, now, half a dozen cases of Kwashiorkor in the last five years,” he


Health-conscious parents, thinking they are doing the right thing, are substituting low-protein alternatives like rice beverages instead of milk in their infants’ diets and causing protein-energy malnutrition. “They think that because this is advertised for adults as a healthy alternative to milk, they can use it in their children,” Dr. Yan said.

“It’s important. We may think of this as one of the historical diseases, something you read out of books, but you may still come across it,” he said. The hospital has seen two cases of

scurvy as well, again due to restrictive diets parents are giving to their children.

Know when to call other specialists

When a 13-year-old boy presented at the hospital having had fevers for three weeks, chills and shortness of breath—which scans revealed to be adenopathy calcifying pulmonary

nodules—the diagnostic team also noticed a single skin lesion and decided to consult with

the dermatology department, Dr. Yan said. “So of the different services [at the hospital], they thought ‘let’s consult derm also. Because there is one skin lesion we should ask them what

is going on.’”

As part of the work-up the derm team took a more detailed history, which revealed a history of tick exposure, he said. A biopsy of the lesion showed some granulomas but no obvious organisms, but the history of tick exposure led the team to request a chocolate agar culture.

“It grew Francisella tularensis, which is the cause of tularemia. So tick exposure, it turns out, is possibly more common than handling raw rabbit for tularemia,” said Dr. Yan.

The takeaway is that for challenging cases in search of a diagnosis, it is important to call on your colleagues, he says.

Don’t forget the Internet

In addition to a physician’ s own expertise and consulting with colleagues, a dermatologist should not overlook the potential power of a Google or Pubmed search to find literature that helps clear up a mystery diagnosis, said Dr. Yan.

When a three-year old presented at the ER with a history of tick bites and a painful lesion on the back of his head, characterized by a darker eschar, a spreading ring of erythema,

and some underlying lymph adenopathy, initial cultures turned up no organisms which seemed to rule out many of the initial hypotheses such as tularemia or some form of

Lyme disease. Consultations with colleagues also did not shed much light onto the situation.

“So I went to Google,” Dr. Yan said. “I typed ‘scalp,’ ‘eschar’ and then ‘adenopathy’ to see

what I find.”

One of the results listed ‘after tick bite', and he followed it.

“What did I see? ‘ Tick-borne lymph adenopathy: an emerging syndrome,’ ‘update on SENLAP,’ which is scalp eschar and neck lymph adenopathy. This was the diagnosis,

essentially,” reported Dr. Yan.

“Some of the patients who have been tested for this, when [doctors] got the test data back they identified Rikettsia organisms as the cause,” said Dr. Yan. “If you want to know

more about it, you can Google it or search Pubmed.”

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