There are 3 main skin manifestations associated with Lyme disease
Erythema migrans
The Erythema migrans (EM) of Lyme disease can take many forms. The best known is a roughly circular red rash, without itching or pain, that slowly spreads outwards and clears from the middle. Often called a bull’s eye rash.
Note that
- The rash does not have to be circular
- The rash can become very large (40cm across) with diffuse edges
- There can be many rashes, not just one
- The rash is not necessarily at the site of the tick bite
- Surveys have shown that around 50% of people do not see a rash
Immediately after an attached tick has been removed from the skin, the site of the bite will continue to be a little red, perhaps for a couple of days – this is not in itself an indication of Lyme disease. The EM develops 2-30 days after the bite.
Acrodermatitis Chronica Atrophicans (ACA)
This is an uncommon, bluish-red discolouration and swelling, on the surfaces of legs and arms, that develops several years after infection. It takes a chronically progressive course and finally leads to a widespread atrophy of the skin.
There is often associated peripheral neuropathy.
Borrelia lymphocytoma
This is uncommon in Europe, and extremely rare in the US. It is a bluish-red, solitary swelling, with a diameter of up to a few centimetres, most often seen on ear lobes or nipples.