Diagnosing and Treating Lyme Disease: A Clinicians Guide to Stages, Symptoms, and Pitfalls

For healthcare providers in tick-heavy regions, Lyme disease remains one of the most challenging diagnoses. Beyond the textbook cases, atypical rashes, early false-negative tests, and overlapping symptoms demand a trained eye.

Heres a breakdown of what you need to know about Lyme disease in 2025, with a focus on recognizing it early, managing it well, and navigating the post-treatment landscape thoughtfully.

Lyme disease is caused by a group of bacteria called Borrelia burgdorferi sensu lato. In the U.S., Borrelia burgdorferi sensu stricto is the main culprit, but in Europe and Asia, Borrelia afzelii and Borrelia garinii are major players too. A few other genomospecies occasionally cause disease, but they are much less common.

In the U.S., Borrelia burgdorferi is primarily transmitted via black-legged ticks, often without the patient recalling a bite. This lack of exposure history makes timely diagnosis a clinical challenge.

Stages and Clinical Presentation

Lyme disease doesnt always follow the textbook, but we traditionally divide it into three stages:

Early Localized Disease
This is the stage most people have heard of: the early red rash called erythema migrans (EM). It usually appears 7-14 days after the bite, but can appear anywhere from 3-30 days later.

Although we often think of the "bulls-eye" rash, most EM lesions are solid red without central clearing. They expand slowly and can grow impressively large sometimes over 20 centimeters (cm) across.

Patients may also complain of mild systemic symptoms: fatigue, headache, low-grade fever, and muscle aches. High fever and upper respiratory symptoms are less common if your patient sounds like they have a bad cold, think twice before jumping to Lyme.

Early Disseminated Disease
If the infection spreads through the bloodstream, patients may show up with multiple EM lesions (not multiple bites this is hematogenous spread), cranial nerve palsy (especially facial nerve), meningitis, or carditis.

Facial palsy is a classic tip-off in children during Lyme season if you see bilateral facial palsy, think Lyme first until proven otherwise. Lyme carditis can present as a fluctuating atrioventricular block; a PR interval > 300 milliseconds is a red flag for potential complete heart block.

Late Disseminated Disease
Months or even years after the initial infection, untreated patients may develop Lyme arthritis, typically hitting large joints like the knee. Its often less painful than septic arthritis, and many kids can still walk despite swelling.

Neurologic late disease (like subtle peripheral neuropathies or encephalopathy) is much rarer today thanks to earlier detection and treatment.

In a study of Connecticut kids with Lyme disease, 89% presented with erythema migrans. A smaller percentage showed up with arthritis, facial palsy, or meningitis. Recognizing that many children (and their parents) dont remember any tick bite is crucial absence of a tick bite history shouldnt rule out Lyme if the story fits.

Younger kids often get rashes on the head or neck, while older kids tend to have them on their limbs.
If a child presents with isolated facial palsy, consider Lyme but remember that serologic tests may be negative early on. If initial testing is negative but clinical suspicion remains high, recheck serology in two to three weeks.

Treatment, Recovery, and Ongoing Care

The term "chronic Lyme disease" gets thrown around a lot, especially online. However, there is no accepted medical definition for this term.

Post-Treatment Lyme Disease Syndrome (PTLDS) is more often discussed. About 515% of patients experience persistent fatigue, joint aches, or brain fog after proper antibiotic treatment. Its frustrating for patients, but research shows long-term antibiotics don't help and can actually cause harm. Supportive care, validation, and a thoughtful approach to symptom management are the best tools we have.

If Lyme disease is diagnosed and treated during pregnancy, outcomes are generally excellent. Theres no evidence that Lyme disease causes congenital abnormalities or that its passed through breastfeeding.

Because ticks can transmit more than one infection at a time, dont forget about coinfections like anaplasmosis, babesiosis, and Borrelia miyamotoi. Watch for signs like persistent high fever, thrombocytopenia, or anemia, especially if the patient isnt improving as expected on typical Lyme therapy.

Lyme disease is highly treatable especially if caught early. Key points to remember:

• The classic "bulls-eye" rash isnt the norm look for any expanding red lesion.
• Early serologic testing can be falsely negative. Trust the clinical picture, especially with EM.
• Most children and adults do well with appropriate antibiotic therapy.
• Be cautious about overdiagnosing Lyme in patients with vague symptoms alone.
• Educate your patients gently about post-treatment symptoms and steer them away from harmful extended antibiotic courses.

The more familiar you are with how Lyme disease behaves at different stages, the more confident youll be in diagnosing and managing it and the more patients youll help avoid long-term complications or unnecessary treatments.
Stay sharp this tick season!

About the Author:
Jennifer "Jenny" Huynh, BSN, RN, NCSN, graduated from the University of Massachusetts Lowell (UMass Lowell) and is certified as a school nurse. She has worked as an RN for six years, focusing on school nursing. Currently, Jenny is working on her Master's in Nursing Education and is an Adjunct Instructor at UMass Lowell.

Jenny is an independent contributor to CEUfast's Nursing Blog Program. Please note that the views, thoughts, and opinions expressed in this blog post are solely those of the independent contributor and do not necessarily represent those of CEUfast. This is not medical advice. Always consult with your personal healthcare provider for any health-related questions or concerns.

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