Migratory redness (erythema migrans) is a redness of the skin that often occurs in the first stage of the tick-borne disease Lyme disease. Typically, migratory redness occurs several days to weeks after a tick bite and spreads in a circular pattern from the bite site. However, migratory redness does not occur in all cases of Lyme disease. In addition, the appearance can be very different and is therefore often difficult to distinguish from other causes of skin redness. If migratory redness is suspected, a blood test for Lyme disease should therefore be performed. If this is positive, treatment with an antibiotic can prevent the progression of the disease.
Cause of wandering redness
Wandering redness is caused by the bacterium Borrelia burgdorferi, which, like the TBE virus, is transmitted to humans through the saliva of a tick. Thus, a tick bite can lead to an infection with Borrelia and thus to Lyme disease. Often, the disease begins with the appearance of skin redness, but Lyme disease without wandering redness occurs in about 10 to 20 percent of cases.
What is wandering redness?
Classic wandering redness is a reddening of the skin that progressively spreads in a circular pattern around the site of the bite after a tick bite. Often, a ring-shaped fade forms, with the tick bite usually clearly visible in the center. Incorrectly, colloquially often spoken of a tick bite, although ticks do not bite the person strictly speaking, but sting.
Recognize wandering redness
Unlike a mosquito bite or a horsefly bite, wandering redness is usually not swollen and is much larger (usually over five centimeters in diameter). Pain and itching tend to be rare, but the area of redness is often overheated. In addition, flu-like symptoms may occur:
- Fever and chills
- Headache
- Tiredness and fatigue
- Nausea
- Muscle and joint pain
- Swelling of the lymph nodes
- Burning, watering eyes
Risk of confusion: atypical wandering redness.
The expression of wandering redness can be very different. A so-called atypical migratory redness is not uncommon and can deviate significantly from the classic circular picture. Thus, the redness in atypical wandering redness can be intense and extensive or only pale and streaky – multiple rednesses distributed over the body are also possible. The color can vary from light pink to intense red to bluish-purple. In addition, wheals, blisters or nodules may occur in atypical wandering redness.
At what point does wandering redness occur?
The onset and duration of wandering redness can vary widely: Usually, the redness occurs 3 to 30 days after the tick bite. How long migratory redness persists is influenced by treatment – the earlier antibiotic therapy is started, the sooner the redness subsides. Usually it lasts a few days to weeks, but the redness can persist for months – this is called chronic migratory redness (erythema chronicum migrans).
What looks similar to migratory redness?
Because of its different appearance, migratory redness is often difficult to distinguish from other forms of skin redness. The following overview can help you delineate possible causes:
- An insect bite itches in most cases, moreover, redness and swelling occur immediately after the bite and subside after a few days.
- In erysipelas, accompanying symptoms such as fever, fatigue and overheating of the skin are usually pronounced. In addition, there is often swelling and pain.
- An allergic reaction to a drug (drug exanthema) is also often accompanied by pain as well as severe itching. In addition, a connection to the intake of a new drug can usually be established – often an antibiotic is the cause.
- Inflammation of the subcutis (hypodermitis), which can occur in connection with venous insufficiency, among other things, is typically manifested by a thickened and hardened redness and often occurs symmetrically on both lower legs.
- Certain forms of the autoimmune disease scleroderma can be manifested by round, reddish skin manifestations. However, a hardening of the skin is also typical here.
- Herpes and shingles are usually accompanied by pain.In addition, it often comes after a few days to a blister.
- In tinea corporis – a fungal disease of the skin – there may be ring-shaped, itchy redness, often scaling and pustules around the edges.
Diagnostics: blood test not always necessary
If the doctor clearly recognizes a typical migratory redness (eye diagnosis), this is evidence of the presence of Lyme disease. Therefore, treatment with antibiotics should be started without further diagnostics – even if the patient cannot remember a tick bite. In unclear cases, various blood tests can be done to diagnose or exclude the wandering redness as symptoms of Lyme disease. This involves testing the blood for antibodies to Borrelia. Rarely, a skin sample (biopsy) is taken from the area of redness to directly detect the pathogens.
Wandering redness: what helps?
Treatment is usually with the antibiotic doxycycline. In pregnancy and in children under nine years of age, however, the active substance may not be used; alternatively, amoxicillin is then usually used, and more rarely cefuroxime or azithromycin. Because itinerant rash is caused by bacteria, creams – such as those containing cortisone – are ineffective.
Therapy: the earlier the better
The duration of treatment is usually two to three weeks. If therapy is started early, the prognosis for wandering redness is very good: a chronic course or a transition to advanced stages of Lyme disease can often be prevented.
Preventing wandering redness
A vaccine against Borrelia does not currently exist. Protection against ticks is therefore the most important preventive measure. If a tick bite nevertheless occurs, the tick should be removed as early as possible (within the first 24 hours). This is because the longer the tick remains in the skin, the higher the risk of transmitting Borrelia bacteria. Afterwards, the puncture site should be observed for six weeks to detect wandering redness at an early stage.
Antibiotic prophylaxis not useful
Prophylactic antibiotic treatment after a tick bite may reduce the risk of Borrelia infection in some circumstances. However, the risk of contracting Lyme disease is generally rather low: in only 0.3 to 1.4 percent does disease occur after a tick bite. Therefore, because of possible side effects, preventive use of antibiotics is not recommended.
