Medically reviewed on July 13, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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If you’re an avid outdoorsperson living in the US, avoiding a tick bite is likely part and parcel of your wilderness safety plan.
Ticks can carry bacteria that can infect humans and other animals—including Lyme disease and Rocky Mountain Spotted Fever.  And, if you’re experiencing symptoms after a tick bite, quick identification can lead to swift treatment and recovery.
In this guide, we’ll break down everything you need to know about Lyme disease vs. Rocky Mountain Spotted Fever (RMSF). We’ll define both illnesses and compare their symptoms, causes, and treatment options to help you stay vigilant during your next outdoor adventure.
Lyme disease is a vector-borne illness—a sickness spread by arthropods like ticks, mosquitoes, and fleas—that impacts approximately 30,000 people in the US each year according to CDC reports. [2,3]
There are three stages of Lyme disease: 
Early intervention can eradicate the disease in the first stage, and treatment outcomes improve the earlier patients, and healthcare providers can correctly identify the illness.
Depending on how far a Lyme infection has progressed, it can take just a few weeks or multiple years to completely eradicate the bacteria from the body—so, adequate prevention is key. If left untreated, long-term effects of Lyme disease could also arise. If you spend significant time outdoors, you can prevent tick bites by: 
Like Lyme disease, Rocky Mountain Spotted Fever (RMSF) is a vector-borne illness transmitted via a Rocky Mountain wood tick or brown dog tick carrying infectious bacteria. 
This infectious disease is significantly less common than Lyme disease—while the number of confirmed cases rises each year, only around 5,000 infections were reported to the CDC in 2019. 
The disease develops in two stages (early and late illness), but symptoms can change rapidly with some late-stage infections setting in only five days after exposure.
RMSF prevention isn’t unlike Lyme prevention, but people who spend ample time outdoors can stay vigilant by:
Let’s explore some similarities and differences between the two illnesses to help you identify and treat each one.
Lyme and RMSF share a few symptoms, including:
But, the rashes that present in each illness are distinct:
RMSF also features a distinct symptom that can help healthcare providers and patients rule out Lyme disease—nausea or vomiting. Lyme infections typically don’t present with gastrointestinal symptoms, so stomach troubles can distinguish an RMSF infection from Lyme.
In addition, a rash typically doesn’t develop in RMSF patients until the second stage. A Lyme disease rash can occur within days after being bitten by an infected tick.
Both illnesses are spread by ticks, but different bacteria are to blame:
Different tick species cause each infection and none of the seven tick species living throughout the contiguous US carry both Borrelia and Rickettsia bacteria. So knowing where Lyme disease is common and where RMSF is common is important. Also, having familiarity with the tick populations living in your region and the bacteria they carry can help you rule out each bacteria during diagnosis. 
Lyme-carrying ticks include:
RMSF-transmitting tick species are the:
Both Lyme disease and RMSF can only be eradicated using antibiotic medications. However, the antibiotics prescribed depend upon the age, pregnancy status, and health history of the patient, and anyone experiencing symptoms of either illness should expect to be prescribed: 
While your healthcare provider will primarily prescribe a course of antibiotics to eliminate the bacteria, they may also recommend over-the-counter (OTC) medications or other remedies, like:
Key differences in Lyme disease vs. Rocky Mountain Spotted Fever can help patients and medical professionals determine a diagnosis. But, if you suspect that you may have a tick-borne illness, you can take action by getting a laboratory test done or taking a test from the comfort of home with a Lyme disease test kit from Everlywell.
Using an at-home test kit can help you and your healthcare provider determine your diagnosis, and completing an Everlywell test is easy:
Everlywell offers digital healthcare solutions designed for you—we’re putting the power of diagnosis, early intervention, and prevention into your hands, giving you access to high-quality testing when you need it most.