The red rash, also known as the ‘erythema migrans’ (EM), is one of the most famous symptoms of Lyme disease.
After a tick bite, a small swelling or spot with in the middle a red dot where the tick used to be can be seen on the skin. This is not the bullseye rash or the ‘erythema migrans’ that people mean when they are talking about Lyme disease. Almost everyone gets this type of skin irritation, comparable to a mosquito bite.
An EM, however, is a red skin rash in the form of a circle or spot, which grows in the course of weeks or months. About half of the patients get such a red circular rash when they have contracted Lyme disease, which means that the other half doesn’t get the characteristically bullseye rash!
An EM is a skin infection that arises 4-10 days after a tick bite.
How to recognize a bullseye rash
In average, the rash grows to about 5 to 40 cm. This is not set in stone! In some cases, the circles were smaller or even covered the entire body. Important is that the circular rash grows. In order to see clearly whether the surface of the rash increases, the patient can take photos every couple of days. Another method is to outline the edge of the spot with a waterproof marker. When the rash surpasses this outline, this is probably an EM. In case of a possible red rash after a tick bite, it is wise to go to the general practitioner.
When a typical erythema migrans is noted, the presence of Lyme Borreliose is very likely. The patient will, therefore, be prescribed antibiotics without doing any further tests.
Variations of the erythema migrans also occur. For example, the spot might remain evenly red, blisters might arise on the spot or multiple circles on top of each other might be visible. Multiple circles all at once or returning EM spots are also known to occur, and the EM might even turn up on a different spot than were a person was bitten by a tick.
The bullseye rash will get smaller again in the course of time. This also happen when you don’t take antibiotics! So, this doesn’t necessarily mean that the bacteria is gone. Don’t wait until the rash disappears, but go see a general practitioner!
Even be careful when this typical Lyme disease rash doesn’t appear
When a bullseye rash doesn’t occur, this doesn’t indicate that someone doesn’t have Lyme disease. The disease might also be present when the characteristic Lyme disease rash is not. According to the literature, this is even the case for 30 to 70% of the infections. It is, therefore, important to watch for flulike symptoms after a tick bite, for this might be an indication for Lyme disease.