What is Erythema Migrans?
Erythema migrans is a rash that appears in the early stages of Lyme disease. Lyme disease is transmitted through tick bites, the infectious agent being known as spirochete Borrelia burgdorferi. This illness is endemic in many parts of the world and it can appear after a period of one day to one month after a person was bitten by an infected tick. Infected ticks are often found on deers but they can appear on other animals as well. It is important to understand that this rash does not appear as an allergic reaction to the bite but it is actually an infection of the skin caused by the spirochete.
In many cases, the presentation of erythema migrans is distinctively enough in order to suggest a diagnosis and the doctor will not wait for the laboratory confirmation before recommending a certain course of treatment. The rash is characteristic for the infection with the spirochete and it is clear that no other parasite will cause this form of rash. Erythema migrans was first identified in 1909, as one of the early signs of Lyme disease and today it is found in people of all ages and genders. It seems that there are a lot of people who acquire Lyme disease and erythema migrans when traveling but the presentation of the rash does appear to depend on the Borrelia species involved.
What does erythema migrans look like?
After a person is bitten by an infected tick, there is the reduced possibility of the body’s immune system being strong enough to repel the infectious agent. However, in the majority of cases, the bacteria will remain at the site of the tick bite and will lead to the appearance of erythema migrans, which is indeed a localized infection of the skin. This is why the presentation of this rash is considered as an early sign, as in the later stages of Lyme disease the infection will disseminate through the blood and lymphatic systems to the internal organs.
The rash can appear as a single red patch that seems to be continuously expanding or as a spot that is surrounded by clear skin. Often times, a second ring surrounds the red rash. In the disseminated form, the rash will appear on various parts of the skin. The initial patches have a diameter of maximum 7 cm and they can be of various types: annular homogenous, central, with central clearing or with purpuric clearing. There is also the oral presentation, in which the oral cavity mucosa presents lesions.
Symptoms of Erythema Migrans
These are the most common symptoms of erythema migrans:
- Circular rash at the site of the tick bite
- Initially, appears as a red macule or papule at the site of the tick bite
- The rash can have various shapes but most often it is round or oval and it has a pink, purple or red color
- Target like appearance (the red rash is in the center, followed by a circle of clear skin and then by the second red rash that has a round shape as well)
- Most commonly affects the back of the knees, the groin area, the axillary area and the thorax. In children, the rash is more obvious on the scalp and the hairline. There is also the possibility of oral involvement.
- Given the fact that erythema migrans is an early sign of Lyme disease, the patient might also exhibit the following symptoms, depending on how far the infection has spread:
In the localized form:
- Single red patch on the skin at the tick bite area
- Lymph glands near the tick bite are swollen and tender
- The patient will present flu-like symptoms, including fever (not high), overall weakness, arthralgia and chills.
In the disseminated form:
- The rash is present on multiple sites
- The patient will present severe fatigue and headaches
- The back portion of the neck is rigid and it hurts a lot
- Tingling or numbness sensation in the extremities
- Facial paralysis
- Sore throat and high fever
- Pulse modifications
- Blurry vision
- Enlarged lymph glands in multiple sites.
In the late, generalized systemic form:
- Pain and joint inflammation
- Neurological modifications, with confusion, memory loss and impossibility to concentrate
- Numbness in upper and lower extremities.
Causes of Erythema migrans
Erythema migrans is caused by the localized infection of the skin that occurs after an infected tick bite. The main culprit behind the appearance of this rash and other manifestation of Lyme disease is spirochete Borrelia burgdorferi.
These are the most common methods of diagnosis for erythema migrans and Lyme disease in general:
- Clinical assessment of the rash and evidence of a tick bite
- Blood tests are recommended when there is no clear evidence of a tick bite and it is important to know that, in the early stages, the results might be negative.
- Laboratory investigations:
- Antibody titres to spirochete Borrelia burgdorferi
- Skin biopsy – the histopathological features are not specific for this particular infection but they can be of help for the actual confirmation of the diagnosis.
- Differential diagnosis can be made with any of the following medical conditions:
- Reaction to tick bite (without any infectious agent)
- Different types of insect bites
- Cellulitis (life-threatening infection of the skin)
- Contact dermatitis
- Other types of erythema.
Erythema migrans Treatment
Even though the rash will disappear on its own, it is important to start the antibiotic therapy as early as possible, so as to prevent the other symptoms of Lyme disease and guarantee a faster recovery. The antibiotic that is commonly used for the treatment of this medical condition is doxycycline; however, this is not recommended for children under the age of twelve, women who are pregnant or those who are breast feeding. Alternatives to doxycycline are amoxicillin and cefuroxime, the treatment being initially administered for at least two weeks. In case these antibiotics are not showing the intended results, the patient can be treated with either azithromycin or clarithromycin, these two being part of the macrolides antibiotics.
When it comes to erythema migrans and other manifestations of Lyme disease, prevention is even more important than the treatment. People from various occupations and of various ages are recommended to avoid exposure to tick bites, especially when traveling in foreign countries. As soon as they have seen that they have a tick on them, immediate removal is mandatory. The longer the tick stays on the skin and connected to the bloodstream, the higher chance for infection. In this way, early removal can prevent the infection from ever happening. Endemic areas also benefit from prophylaxis with above mentioned antibiotics, especially if there are a lot of cases of tick bites in a specific area.
Is erythema migrans contagious?
Erythema migrans is one of the signs of Lyme disease, which is extremely contagious. A new study published in the Journal of Investigative Medicine has even suggested that Lyme disease, along with all of its manifestations, is transmitted sexually from one partner to the other. You can also catch it from pets, as these can have infected ticks on them as well.
If you are going outdoors, then you need to protect yourself as best as you can. This means you should wear light colored clothes as this will make ticks easier to spot. Also, you should tuck your pants into your socks to create a barrier against ticks and not leave your skin directly exposed. Insect repellent can also be of help, especially since ticks are not the only insects present in the woods or in the forest.
Make sure that you stay away from areas with excessive vegetation or there is a lot of moisture, as those are places where ticks thrive. Inspect everyone after you have been outside and make sure that any tick you find is instantly but gently removed. A sudden removal can leave the head of the tick still attached to the skin, increasing the risk for infection. Also, you should know that the spring and the summer are the two months when you need to be more aware of tick bites. Removing a tick as soon as you have seen it is the best way to guarantee that you will not suffer from erythema migrans and other signs of Lyme disease, plus that you will not pass it on to others.
Erythema Migrans Pictures
Collection of photos, images and pictures of Erythema Migrans…