There are 500K new cases of Lyme disease each year in US; many don't remember tick bite

Q:  I have not heard much about Lyme disease this year, is it no longer an issue?

A:  I think talk about Lyme disease has taken a back seat to COVID, Monkeypox, mass shootings and other issues, but it remains a significant health issue with about 12% of people in the U.S. having been infected in their lifetimes and up to 500,000 new cases per year.

Lyme disease is due to the spirochete Borrelia burgdorferi transmitted by a tick bite, even though only about a quarter of people who get it recall the bite.  Although the very small deer ticks are the most common culprits, any tick may transmit the disease. The risk of getting Lyme disease is extremely small unless the tick is attached for over 24 hours.

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If you find a tick it should be removed immediately by grasping it as close to the skin as possible (do not squish it), and gently but firmly pulling it away off (forceps or tweezers may be useful). Prophylaxis after a tick bite depends on the circumstances; if the tick has been on for 24 to 72 hours, then one dose of appropriate antibiotic is indicated.

Lyme disease is often broken up into ‘stages’ of the disease.

Stage 1 (early localized) Lyme disease: Three to 32 days after the tick bite the patient may develop a rash at the site of the bite which is red and then clears in the middle (so it looks like a bull’s eye ‘target’ lesion).  This rash will typically last 2-3 weeks in untreated patients, and about 20% will have this rash recur.  After this initial rash about 40% of untreated patients get similar looking rashes on other body locations.

About one-third of patients will not develop any symptoms other than the rash. The remaining two-thirds will develop flu-like symptoms possibly including a headache, fever, chills, a stiff neck, muscle and/or joint aches, and/or fatigue. Some people get swollen glands, sore throat and/or a cough.

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The diagnosis of stage 1 Lyme disease is made clinically based on the symptoms and the risk for having had a tick bite (e.g. someone from an endemic area who lives or works in a wooded area); blood tests are not very reliable in early Lyme disease because early antibody response may be limited.

Treatment of stage 1 Lyme disease is usually quite effective, and typically consists of a course of oral antibiotics.

Stage 2 (early disseminated) Lyme disease: This can occur weeks to months after the tick bite, and while almost all patients will have malaise and fatigue, many other organ systems can be involved as well.

Most patients with stage 2 disease will have intermittent transient bouts of arthritis. This usually begins as a mild arthritis of several joints, which seems to "settle" into a single joint over a day or two – the knee, ankle and wrist as the most common locations.  Untreated, the arthritis will usually last a week or so and then resolve on its own, with most patients having recurrent bouts every two to three months. Subsequent bouts of arthritis are usually less severe than the initial bout, but can involve multiple joints.

Neurologic symptoms manifest in about 15% of stage 2 patients, and can include chorea (irregular spasmodic movement of the muscles), meningitis-like symptoms, Bell’s palsy (drooping of one side of the face, including the forehead, which can make it impossible to shut your eye all the way even while sleeping, and may make you drool when you drink) or other neurologic symptoms.

About 8% of patients will develop heart problems including changes in the electrical conduction of the signals that make the heart beat (first degree, second degree or even complete heart block), inflammation of the heart muscle or even decreased function (squeeze) of the left ventricle.

Diagnosis of stage 2 Lyme disease is once again based on the clinical picture, however blood tests are usually done to help confirm the diagnosis. Unfortunately, the sensitivity and specificity of these tests is limited, with false positive and false negative tests not uncommon, so these tests are just one additional piece of information.

The treatment of stage 2 Lyme disease is once again antibiotics, with the length of treatment and route of administration (by mouth or intravenous) depending on the specific symptoms, and whether the patient had prior antibiotic treatment.

The symptoms of stage 3: (for this article I will include late disseminated, post-treatment or chronic LD in this category), occur in as many as 10% to 20% of patients, and may manifest many months after the initial tick bite, and despite previous treatment with antibiotics. Symptoms include fatigue/malaise (which can be severely debilitating), joint or muscle pain/stiffness, neurocognitive/psychiatric symptoms, and/or others.

The diagnosis is based on the clinical picture; blood tests are usually done but may be unreliable, particularly in patients treated with antibiotics early in the course of their disease (who may not have developed high levels of certain antibodies and so may ‘test negative’).  In addition, for unknown reasons, other patients may not build measurable antibody levels.

Treatment response for people with stage 3 Lyme disease, especially chronic Lyme disease, shows inconsistent results, so treatment must be decided on a case-by-case basis.

A good way to prevent Lyme disease is to closely check your body for ticks at least once a day any time you have been in a situation that might have put you at risk (camping, hiking, etc.).  If you have had a tick bite, consult your doctor to discuss whether prophylaxis is indicated.

Jeff Hersh, Ph.D., M.D., can be reached at DrHersh@juno.com.

This article originally appeared on MetroWest Daily News: Lyme disease is caused by a tick bite, mostly deer ticks