Redness: warning signal after a tick bite

Redness: warning signal after a tick bite

Erythema migrans is a reddening of the skin that often occurs in the first stage of tick-borne Lyme disease. Typically, the reddening occurs a few days to weeks after a tick bite and spreads in a circle from the bite site. However, not all cases of Lyme disease lead to a blush. In addition, the appearance can be very different and is, therefore, often difficult to distinguish from other causes of skin redness. If erythema is suspected, a blood test for Lyme disease should be carried out. If this is positive, treatment with an antibiotic can prevent the disease from progressing.

What is blush?

The classic reddening is a reddening of the skin that increasingly spreads in a circle around the bite site after a tick bite. A ring-shaped pallor often forms, with the tick bite usually visible in the middle.

By the way: In colloquial language, it is often incorrectly referred to as a tick bite, although strictly speaking, ticks do not bite people but sting them.


cause of erythema

Blushing is caused by the bacterium Borrelia burgdorferi, which, like the TBE virus, is transmitted to humans via tick saliva. A tick bite can lead to an infection with Borrelia and thus to Lyme disease.

reddening without a tick bite is also possible: Borrelia has already been found in mosquitoes, black flies, horseflies and fleas, so reddening can also occur after a mosquito bite, for example. However, this is very rare – the tick bite is probably not noticed in most cases.

Lyme disease often begins with the appearance of reddening of the skin. However, Lyme disease without erythema occurs in 10 to 20 per cent of cases.

recognize redness

Unlike a mosquito or horsefly bite, the migratory flush is usually not swollen and is significantly more extensive (usually more than five centimetres in diameter). Pain and itching are rare, but the area of ​​redness is often overheated.

In addition to the typical ring-shaped reddening, flu-like symptoms can occur:


When does migraine appear?

Occurrence and duration of redness can vary greatly: redness usually appears 3 to 30 days after the tick bite. The treatment influences how long the blush persists – the earlier antibiotic therapy starts, the sooner the redness will subside.

The duration is usually a few days to weeks, but the redness can also persist for months – this is then referred to as chronic redness (erythema chronicum migrans).

Likelihood of confusion: atypical redness

The expression of the blush can be very different. A so-called atypical reddening is not uncommon and can deviate significantly from the classic circular picture.

The reddening of atypical reddening can be intense and widespread or only pale and streaky – several reddenings distributed over the body are also possible. The colour can vary from light pink to intense red to bluish purple. In addition, wheals, blisters or nodules can occur with atypical erythema.

Also, one should distinguish the redness from the considerable one- to two-centimetre reddening that typically forms immediately around the tick bite. This reddening is often very itchy but is harmless and usually disappears after a few days.

What looks similar to a migratory blush?

Because of the different appearances, erythema is often difficult to distinguish from other forms of skin reddening. It is, therefore, easily confused with other causes. The following overview can help you to define possible causes:

  • In most cases, an insect bite is itchy, and redness and swelling appear immediately after the bite and subside after a few days.
  • In the case of erysipelas (erysipelas), accompanying symptoms such as fever, exhaustion and overheating of the skin are usually very pronounced. In addition, there is often swelling and pain.
  • An allergic reaction to a drug (drug eruption) is also often accompanied by pain and severe itching. In addition, a connection to the intake of a new drug can usually be established – an antibiotic is often the cause.
  • Inflammation of the subcutaneous tissue (hypodermatitis), which can occur in connection with venous insufficiency, is typically manifested by thickened and hardened redness and often occurs symmetrically on both lower legs.
  • Specific forms of the autoimmune scleroderma can manifest as round, reddish skin lesions. However, hardening of the skin is also typical here.
  • Herpes and shingles are usually accompanied by pain. In addition, blisters often form after a few days.
  • Tinea corporis – a fungal skin disease – can lead to ring-shaped, itchy, reddening, often flaking around the edges and forming blemishes.


Diagnosis: A blood test is not always necessary

If the doctor recognizes a typical reddening (visual diagnosis), this is proof of the presence of Lyme disease. Therefore, antibiotic treatment should be started without further diagnostics – even if the affected person cannot remember a tick bite.

In unclear cases, various blood tests can be carried out to diagnose or rule out erythema as a symptom of Lyme disease. The blood is examined for antibodies against Borrelia. Rarely is a skin sample (biopsy) taken from the area of ​​reddening to be able to identify the pathogen directly.

Red blush: what helps?

Treatment is usually with the antibiotic doxycycline. However, the active ingredient must not be used during pregnancy and in children under nine. Alternatively, amoxicillin, more rarely cefuroxime or azithromycin, is usually used.

Since erythema is caused by bacteria, creams – such as those containing cortisone – are ineffective.

Therapy: The sooner, the better

Some people are unsure when to see a doctor if they suspect erythema. A visit to the doctor’s consultation hour is always recommended in such a case. If therapy is started early, the prognosis for erythema is excellent: a chronic course or a transition to advanced stages of Lyme disease can often be prevented in this way.

The duration of the treatment is usually two to three weeks.


Prevent migraine

There is currently no vaccine against Borrelia. Protection against ticks is, therefore, the most important preventive measure. If a tick bite does occur, the tick should be removed as early as possible (within the first twelve hours). Because the longer the tick is in the skin, the higher the risk of transmission of Borrelia. Removing the tick as carefully as possible is essential to prevent transmission during removal.

The puncture site should then be observed for six weeks to detect early redness.

Antibiotic prophylaxis is not valid.

Prophylactic antibiotic treatment after a tick bite can reduce the risk of Borrelia infection. However, the risk of contracting Lyme disease is generally relatively low: in just 0.3 to 1.4 per cent, a tick bite causes an illness. 

Due to possible side effects, preventive use of antibiotics is therefore not recommended.


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