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I should precede this by noting that rashes are one of the most common reasons I see pediatric patients in the urgent care. Sore throats are hands down the most common reason, followed by asthma-related issues… but rashes are well up there, probably more common than lacerations or other trauma. What nobody ever put in the Official Parents’ Manual, however, is just how common rashes are in kids. Kids practically develop a rash if you even look at them wrong. The vast majority of pediatric rashes are due to a viral cold, eczema, strep, minor trauma, or other transitory cause that is of little long-term danger, which makes it very tempting for the physician to blow off yet another pediatric rash, no matter how experienced and well-trained they are.

A 7 year old Hispanic male presented with, well, a rash. The rash involved all four extremities at the further ends (what we call “distal”). The mother stated that the rash started in the palms of the hands and soles of the feet, before spreading up his wrists and ankles. The rash involved irregular red spots, ranging from tiny dots to irregular shapes no more than 1 cm diameter. The spots were blanching, meaning they turned white when pressed with a finger. The child thought one or two might have been vaguely itchy; he was not sure. Mother stated that he had tactile fevers and body aches about 3 days prior to presentation; the rash appeared 1-2 days ago. He had no other issues such as cough, sneezing, headache, trouble breathing, pain, sore throat, trouble with vision. He had no past medical history of other problems, and he took no medications. The mother denied any new foods, laundry detergents, soaps, animals in the house, or other known new exposures. The child did not have a rash anywhere else, including inside his mouth. Thee mother stated that they had stayed at a religious camp in a rural area, near a forest in a mid-Atlantic state, about one and a half weeks ago. Exam was normal besides the rash discussed above. Mother and child could not recall any insect bites. They could not recall any other recent rashes.

I left the room and did some online research to confirm my suspicions, after which:

AT THIS POINT I WAS 100% SURE OF THE DIAGNOSIS. WHAT IS YOUR GUESS?

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Rocky Mountain Spotted Fever

There are a number of tick-borne diseases in America, and none gets anything close to the attention afforded to Lyme disease. Chronic Lyme disease has wide-ranging yet often nebulous complications if untreated. Because its chronic problems are tough to describe, it has led people to put it up there with glutens and vaccines as the sinister agent behind anything and everything that ails them, from joint pains to fatigue to attention deficit disorder. And the media attention to Lyme therefore remains a steady drumbeat that never really fades.

This is a bit of a shame, because while Lyme gets all the press, it is Rocky Mountain Spotted Fever (RMSF) which is by far the most lethal of the tick-borne diseases in the United States. Even today, its mortality remains in the 3%-5% range, partly due to the fact that it is hard to diagnose, like all tick-borne diseases. If that doesn’t sound bad enough, consider: in the pre-antibiotic era, its lethality approached 30%, or close to 1 to 3 patients – which, therefore, are the odds you face if it is left untreated. And its name is highly inaccurate: it is found in the vast majority of states in the US, with no specific preference for the Rockies, often overlapping areas with Lyme.

dotted handsBefore that patient, I had never personally seen a case of RMSF. This was no surprise, as it has an annual incidence of only 800-1200 cases a year in the USA, versus ~30,000 for Lyme. As stated, most pediatric rashes are nothing to worry about. But on the other hand, rashes that involve the palms and soles are actually red flags. It might just be a fairly benign coxsackievirus that causes something called hand-foot-mouth disease, but it could be something far more grave. If you learn only one thing about pediatric dermatology, let it be that!

I also felt no shame in doing some research, and neither should any doctor, no matter how much more experienced they are than me. I had ever personally seen a case of RMSF, and you better believe I was going to consult some online resources before making that highly unusual diagnosis. All those books in the offices of the old-timey doctors are there for more than just show – some cases really did require they bring down the Harrison’s and look things up. Do not expect your doctor to have a 100% encylopedic knowledgebase of everything in medicine. Hell, you can’t even expect a specialist to know 100% of everything in his own field, let alone everything else. The doctor you should be concerned about isn’t the one who looks up your condition in a book, or Emedicine, or Uptodate. You should be concerned about the one who doesn’t.

Back to the case: RMSF’s namesake rash does indeed start at the soles and palms, spreading inward as it did with this child. I was lucky in that my patient was a child, because (as noted previously) children get rashes at the drop of a hat, and therefore develop the characteristic “spotted” rash sooner and more frequently than adults. Absent the rash, the symptoms of early RMSF are maddeningly vague: fever, body aches, headaches. Any routine virus can do the same thing. The biggest credit in this case has to go to the child’s astute mother who may have possibly saved his life by bringing him in.

I drew bloodwork and immediately started him on the antibiotic doxycycline, which is the drug of choice for RMSF (and most other tick-borne diseases, incidentally). The incident merited a report to the health department, which then basically took over the case. The patient’s parents were told to bring the child to a nearby academic hospital for follow-up, and he must have made for one hell of a teaching case for the residents. The mother reported that the child’s rash got better after one day on the antibiotic, which helped confirm the diagnosis – if the rash fails to improve on doxycycline, RMSF may not be the correct diagnosis. The health department called me later and let me know they were treating his sister for RMSF as well.

RMSF is a rare condition, but one that people should keep in mind given its relatively high mortality. If you or a loved one get bitten by a tick, please seek medical attention at the first sign of a new rash occuring within the first couple of months.

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