Bartonella may be the most overlooked of the infections that travel in Lyme disease’s orbit. Its symptoms are vague enough to be blamed on stress, its rash is routinely mistaken for stretch marks, and standard blood tests miss it with frustrating regularity. Here’s how Bartonella presents, why testing is so difficult, and when it deserves a place on your differential.
Medically reviewed by Elyssa A. Blissenbach, MD, board-certified internal medicine physician.
What Is Bartonella?
Bartonella is a genus of bacteria that live inside blood vessel linings and red blood cells — a stealthy location that helps them evade both the immune system and antibiotics. The best-known species, Bartonella henselae, causes cat scratch disease and is classically transmitted by the scratch or bite of a cat carrying infected fleas. Other species spread through body lice and sand flies. Whether ticks transmit Bartonella directly is still under scientific study — but in practice, Bartonella is one of the infections physicians most often evaluate alongside Lyme disease, because patients with tick exposure and persistent symptoms frequently test positive for it. Our overview of Florida co-infections covers how these infections cluster.
What Are the Symptoms of Bartonella?
Classic cat scratch disease is usually mild: a small bump at the scratch site, followed by swollen, tender lymph nodes near it, sometimes with fever and fatigue. In healthy people it often resolves on its own.
The persistent, systemic form is a different animal. Symptoms commonly include:
- Profound fatigue that rest doesn’t repair
- Headaches, often daily
- Neurological and psychiatric symptoms — brain fog, memory problems, and notably new anxiety, irritability, or mood swings out of proportion to circumstances
- Bone pain, classically in the shins, and migrating joint or muscle pain
- Pain in the soles of the feet, especially with the first steps of the morning
- Swollen lymph nodes, low-grade fevers that come and go
- Eye problems such as blurred vision or inflammation
In immunocompromised patients, Bartonella can cause serious complications, including infections of the heart valves — it is a recognized cause of “culture-negative” endocarditis — which is one reason persistent unexplained symptoms deserve a physician’s evaluation rather than self-management.
The Skin Marks That Look Like Stretch Marks
One of Bartonella’s most distinctive calling cards is a set of linear, reddish-purple marks — often on the back, flanks, or thighs — that look remarkably like stretch marks (striae) but appear in people with no reason to have them. If you’ve noticed marks like these, our guide to what a Lyme vs. Bartonella rash looks like shows the visual differences in detail.
When Should Bartonella Be Suspected Alongside Lyme Disease?
The common story: a patient is treated for Lyme disease, improves partially, but is left with symptoms that don’t fit — especially neurological and psychiatric ones. When anxiety, brain fog, shin pain, or sole-of-foot pain dominate the picture, or when neurocognitive symptoms persist after Lyme treatment, Bartonella moves up the list. Our side-by-side Bartonella vs. Lyme comparison breaks down how the two differ.
Why Is Bartonella So Hard to Test For?
Three reasons. First, the bacteria live inside cells and cycle in and out of the bloodstream, so a blood sample on any given day may simply not contain them — PCR tests can be falsely negative. Second, antibody tests (the standard IFA IgG/IgM serology) depend on a measurable immune response, and Bartonella is adept at suppressing exactly that; seronegative infection is well documented. Third, antibody levels fade over time even in ongoing infection. It’s a similar problem to why Lyme tests come back negative: a negative result narrows the odds but doesn’t close the question. Specialty labs offer more sensitive methods (enrichment cultures, digital PCR), and an experienced physician weighs results against the clinical picture rather than treating any single test as the verdict.
How Is Bartonella Treated?
Treatment depends on the form. Uncomplicated cat scratch disease in a healthy person often needs only observation, or a short course of azithromycin for bulky lymph node involvement. Persistent or systemic infection typically requires longer courses and frequently combination antibiotic therapy — doxycycline or azithromycin paired with rifampin is a common backbone, with regimens individualized to symptoms and response. For stubborn cases, advanced protocols exist: see our articles on Bartonella treatment options and the Dapsone protocol. Treating Bartonella alongside Lyme disease, when both are present, tends to matter — unaddressed co-infections are a common reason Lyme treatment underdelivers.
Frequently Asked Questions
Can Bartonella go away on its own?
Classic cat scratch disease often does in healthy people. The persistent systemic form generally does not resolve untreated — and in immunocompromised patients, Bartonella can become dangerous. Persistent symptoms warrant evaluation.
Do ticks spread Bartonella?
Direct tick transmission hasn’t been definitively proven and remains under study. Established routes are cat scratches and bites (via infected fleas), body lice, and sand flies. In clinical practice, however, Bartonella frequently turns up in patients evaluated for tick-borne illness, which is why it’s routinely considered alongside Lyme.
What does a Bartonella rash look like?
Most distinctively: linear reddish-purple streaks resembling stretch marks in places stretch marks don’t belong. See our visual guide for photos and comparisons.
How long does Bartonella treatment take?
Uncomplicated cases may need a single short course. Persistent infections are usually treated for several months with combination therapy, adjusted to response. Your physician will set expectations based on your presentation.
Northeast Florida Internal Medicine treats Lyme disease, Bartonella, and other tick-borne illnesses in person in Jacksonville and via telemedicine for patients in Florida, Georgia, Alabama, South Carolina, North Carolina, and Virginia. Contact us to schedule a consultation.
This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified physician with any questions about a medical condition.