So your patient brought you a tick…

It’s hiking season and being outdoors is still the safest place to be in the pandemic. One day, your patient brings you a tick she found on her shoulder. Do you:

1. Send it for tick analysis?
2. Start her on a two week course of doxycycline?
3. Draw a tick panel and test for Lyme disease?

As chilling as it is to find one of the little creepy critters on the skin, if discovered in the first 24-36 hours, there is virtually no chance of contracting Lyme from that tick bite. (1)

In order to catch Lyme disease from a tick, several things must happen. First, the tick must be carrying Lyme. Despite that obvious fact, we no longer send ticks for analysis. Carrying Lyme does not mean Lyme was transmitted, and if the patient visits an environment where ticks abound, even if this one is negative for Lyme, a previous tick bite, unbeknownst to the patient, might have caused infection. Often patients are disappointed, but I tell them I am a human doctor; I don’t treat insects. Besides, both deer ticks and dog ticks have been known to carry Lyme, so identifying the tick does not offer useful information.

A tick that is carrying the Lyme vector will attach itself to the skin and settle in to feed. It takes it’s time, generally 24-36, but up to 72 hours, at which point, you will notice it to have become engorged. It is after the tick has satisfied its bloodthirsty appetite that it will pass the Lyme vector—if it is carrying one. If a patient reports an engorged tick or a tick that has been attached for an unknown period of time, prophylactic treatment of 200 mg of doxycycline is indicated as a single dose.

Shouldn’t we start all our patients on two weeks of doxy right away? Ouch. Not only are the GI effects of doxycycline frequently disruptive, but we would then be committing them to two weeks without direct sunshine due to the possible increased photosensitivity effect. And then there are the risks of C. difficille, yeast candidiasis, thrush, aggravation of IBS, etc. Who wants to take antibiotics for two weeks if it’s not needed?

How about blood tests? Never a bad idea, just remember your initial test will not be relevant for this exposure. It’s too early. You are getting a baseline to look for previous Lyme infection which may not have become symptomatic yet but which may be lying in wait. You may also have a positive result if the patient had Lyme in the past and has recovered, but the titers have lingered.

The more important test is four to six weeks later, when the presence of Lyme would have precipitated an antibody response. Whenever you test, it can make sense to test for multiple tick-borne illnesses, and frequently, your local lab will have a standardized profile.

Testing for Lyme should be done sooner if a flu-like illness or a rash consistent with erythema migrans appears. If the patient presents with a target lesion rash, or fever and myalgias with history of a tick bite, then the laboratory assessment should be done immediately at the first visit along with initiation of standard antibiotic treatment.

These little varmints are so tenacious! Should we burn them off? Suffocate them with oil? Dowse them with viscous lidocaine to send them into a stupor? Removing a tick and leaving his little legs behind in your patient’s skin is frustrating, and, let’s face it, awkward. We’re supposed to be the pros, right? But there is a near-foolproof method.

While most advice you’ll find explicitly says do not twist the tick, the thinking is to take care to avoid breaking the critter’s little legs off and leaving them in the patient’s skin. Here is a method that is tried and true if you do it gently: Grasp the body of the tick firmly with forceps (without teeth), but do not squash it. Holding it securely, gradually rotate the body. It may take five or six revolutions, but eventually, the poor critter will get his legs so twisted up, that he will voluntarily just let go, and the tick will come off with all his body parts intact. If it fails with clockwise rotation, switch to counterclockwise. So far, this technique has never let me down. You will remove the tick in its entirety and you will look to be the hero in full measure. Unless, of course, the patient has already been picking at it; in that case, you’re on your own! But usually you do not need to dissect out all the little tick parts; the body will expel them in a few days. You may choose to treat with mupirocin to prevent skin infection.

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Please note: This is not a definitive discussion of Lyme. There is not sufficient space in this blog to review all treatment options or complications of later stage Lyme disease.

References:

 (1)   https://www.niaid.nih.gov/diseases-conditions/lyme-disease

 (2)   https://www.mayoclinic.org/diseases-conditions/lyme-disease/diagnosis-treatment/drc-20374655