Lyme disease is transmitted when infected ticks bite human beings. Ticks in their nymph stage are more likely to cause the infection because they are tiny and invisible. However, a characteristic rash on the skin surface may be noticed sooner after infection. The skin rash is known as erythema migrans which is red and circular around the place of the tick bite.
The rash usually appears within three to fourteen days after the bite of an infected tick. The rash then continues to grow larger with time, and sometimes more rashes may appear with varying sizes and shapes. The most common places where such rashes may appear are the thighs, armpits, trunk, and groin. Over time, as the rash grows larger the center of the rash, usually the point of the bite starts to clear forming a “bull’s eye” appearance. The rash is generally warm but painless.
It is sometimes possible to experience rashes after around the site of a tick bite but not necessarily caused by Lyme disease. Tick saliva may also be responsible for an allergic reaction which causes skin rashes which may be confused with that caused by Lyme disease. To differentiate the two, usually rashes resulting from allergic reactions to tick bites appear within hours to few days after the bite but will not expand and soon disappear.