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Lyme Disease

Anand Swaminathan, MD and Justin Hensley, MD
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Even though Lyme disease is  named after a small town in Connecticut, it’s found on several continents. Whether or not prophylaxis is indicated depends on the type of tick (so hard to tell!), length of exposure and incidence of disease in the area.


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Kelsey G. -

Hi --- Do you have PDF or citation for review about children taking doxycycline?

Mike W., MD -

Hi Kelsey, and thx for the question. Here is the response from the authors of this segment:

Here's the comment from Justin Hensley:(this is posted on EMRAP as well)
Sadly, I named the wrong "C" group. It was the CDC (with the IHS). And yes, you're using it "off-label", as the FDA still has the warning against kids under 8 simply due to the dental staining. The original data for staining was from papers published in 1958, 1962, and 1967, and they all tested tetracyclines that bind calcium. Doxycycline wasn't on the market until 1967 and doesn't bind calcium as well. Unfortunately, they haven't gone back and looked at the warning in almost 50 years.
However, here's the May 2015 paper from the Journal of Pediatrics:
"This study failed to demonstrate dental staining, enamel hypoplasia, or tooth color differences among children who received short-term courses of doxycycline at <8 years of age. Healthcare provider confidence in use of doxycycline for suspected RMSF in children may be improved by modifying the drug’s label."
Dental staining isn't significant with doxycycline even with multiple courses of 7-10 days (kids had an average of 1.8 courses in the paper).
Another source is the March 2007 Clinical Pediatrics:
"The aim of the study was to determine if doxycycline causes tooth staining in young children. A dentist examined 31 randomized children who had been treated with doxycycline and 30 children who had not received doxycycline. Mean age of the children was 10.4 ∓ 2.1 years. Mean age at receipt of the first doxycycline treatment was 4.1 ∓ 1.6 years, and mean number of doxycycline courses was 2.0 ∓ 1.3. No tooth staining was detected by the dentist in any of the children in either group. These findings indicate that treatment with doxycycline in children aged 2 to 8 years is not associated with tooth staining."
And then, most recently (Aug 2016), in Archives of Diseases in Childhood, they reviewed doxycycline in children.
"Clinical bottom line: The risk of dental staining with short courses of up to 10 days doxycycline in children <8 years of age (outside the neonatal period) is negligible (<1%) (Grade B).
Side effects of longer courses or doses exceeding 2.9 mg/kg twice daily require further study (Grade B).
There are insufficient data on dental adverse effects with exposure in the neonatal period (Grade D)."
Since the Lyme dosage is 4mg/kg/day, or 2mg/kg twice daily, and most neonates aren't hiking in the woods, I would argue that there's enough evidence for expanding the age range of doxycycline.

David J. -

In the podcast there's discussion of what to do when you're deciding between similar-appearing cellulitis and rash associated with Lyme-- the theme is to use something that would cover both conditions, but how long of a course would you recommend? In a standard cellulitis many antibiotics are recommended for about 7 days of use, but with Lyme it's 14- 21 days. Should we aim for a happy medium like 10 days?

Mike W., MD -

Hi David, good question. This situation will be pretty rare but it is true that sometimes differentiating these 2 entities will be difficult. If both are in play, I would treat for the more serious potential cause, lyme, with a 14-21 day course. Thx!

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Heart Score, PECARN and A Twist of Lyme Full episode audio for MD edition 175:52 min - 83 MB - M4AHippo Urgent Care RAP July 2016 Summary 549 KB - PDF