The Diagnosis of Lyme Disease

Lyme disease is the best-known tick-borne disease in the world. Fortunately, its diagnosis is simple and is based on the detection of antibodies against the bacteria.
The Diagnosis of Lyme Disease

Last update: 10 August, 2021

Ticks are vectors of many infectious pathologies that can seriously affect our health. Most of these conditions are detected based on the clinical manifestations of the patient and with the support of complementary laboratory tests. Here’s everything you need to know about the diagnosis of Lyme disease.

Infection occurs from a bite by contaminated ticks anywhere on the body. Studies suggest that this pathology is common in the summer and is characterized by a series of skin changes accompanied by symptoms similar to those of the flu or the common cold.

Thus, clinical examination and antibody detection tests are essential in the definitive diagnosis of Lyme disease.

Clinical examination

Assessment by a health professional is the first step in identifying this pathology. In this sense, the specialist will carry out a detailed questioning of the symptoms that the person is suffering from, as well as the circumstances of their appearance. In general, data such as living or traveling to endemic areas are of great value for clinical diagnosis.

Similarly, a comprehensive physical examination usually provides a broader picture of the patient’s condition. In most cases, this condition comes with erythema migrans, the result of a tick bite.

This is characterized by a red spot on the skin that gradually expands until it reaches about 30 centimeters (12 inches), with a clear center in the shape of a target.

In the initial stages, the appearance of small papules as a result of the inoculation of the infection is frequent. They usually appear in the folds and moist areas of the body such as the groin, the gluteal region, the back of the knees, and the scalp.

In addition, affected people often have other symptoms such as headache, fever, fatigue, and muscle aches.

Lab tests

Lyme disease diagnosis includes blood samples
Many of the tests to diagnose Lyme disease require a blood sample. This is also good for ruling out other conditions.

Laboratory tests are generally helpful in the definitive diagnosis of Lyme disease. Some research affirms that this pathology is divided into three stages that include an early localized phase, an early disseminated phase, and a late phase. For this reason, the clinical and laboratory characteristics may vary at each stage, resulting in a great clinical challenge.

In most cases, bacterial infections are detected by isolating the pathogenic microorganism from body fluids. However, the identification of the bacterium Borrelia spp. can be a real challenge due to its invasive properties. This fact highlights the need for the detection of antibodies in blood as the main diagnostic method.

Blood test

Blood tests are used to evaluate red blood cell, white blood cell, and platelet counts. In this way, it’s possible to suspect a bacterial infection due to an elevation of leukocytes with a predominance of neutrophils. On the other hand, the results obtained help us detect if the patient is suffering from anemia or has any alteration in platelet capacity.

Blood tests are used in the differential diagnosis of other pathologies that are responsible for the skin rash. In this sense, acute phase reactants such as C-reactive protein and erythrocyte sedimentation rate may be useful in the detection of new-onset inflammatory conditions.

Enzyme immunoassay (ELISA)

This is a laboratory method that uses enzyme-linked antibodies to identify the antibodies produced by the body against infection with Borrelia spp. Studies affirm that this is the most widely used test in the diagnostic approach of Lyme disease.

In the event that the result is positive or indeterminate, a Western Blot test should be carried out.

However, the ELISA may not detect the antibodies in the first weeks after the bite, giving false negatives. This is because, during this period, the immune system hasn’t produced enough antibodies against the bacteria.

Likewise, early use of antibiotics can reduce the number of antibodies needed for the test to be positive.

Western blot

This is an immunoassay technique that offers great sensitivity in the detection of specific proteins within a biological sample.

It’s used as part of the definitive diagnostic protocol for Lyme disease when the ELISA analysis shows positive or unclear values. Their false positive rate is very low, but they can occur in the early stages.

Lumbar puncture test

A lumbar puncture is a diagnostic option prescribed by the treating physician when a central nervous system is suspected as a complication of this pathology. Some suggestive symptoms include stiff neck, prolonged and severe headache, and papilledema. This test allows detecting conditions such as meningitis or myelitis caused by Borrelia spp.

Differential diagnostics

The diagnosis of Lyme disease is relatively straightforward
Differential diagnoses depend on the stage of the disease. For example, symptoms may sometimes mimic infectious mononucleosis.

The skin manifestations, general symptoms, and long-term side effects of Lyme disease can be confused with many different pathologies. In most people, it’s vital to perform a differential diagnosis with other dermatological conditions, flu syndromes, or pathologies of systemic compromise, among which the following stand out:

  • Infectious mononucleosis
  • Rickettsiosis
  • Babesiosis
  • Influenza
  • Rheumatoid arthritis
  • Multiple sclerosis
  • Acute rheumatic fever
  • Ehrlichiosis
  • Juvenile idiopathic arthritis
  • Lymphocytic meningitis

Early diagnosis reduces the risk of multi-organ complications

Currently, the diagnosis of Lyme disease is based on symptoms, epidemiological characteristics, and the results of antibody detection tests. Its timely identification is associated with a better prognosis and a better quality of life.

However, its late approach increases the probability of suffering from joint, neurological, and cardiac alterations.

For this reason, if you live in an area that’s endemic for this condition and have skin symptoms after being in contact with a tick, don’t hesitate to seek medical assistance. Health professionals are trained to care for your condition and guide you in the detection and treatment of the disease.

Find out all about the causes of Lyme disease in the following article.

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