Erythema chronicum migrans is early skin manifestation of Lyme disease and occurs in around 80-90% of the patients with Lyme disease. Erythema migrans usually appears 7-10 days after the tick bite. Erythema migrans generally resolves spontaneously after 4-10 weeks, but may persist for as long as 6 to 12 months.
Erythema chronicum migrans appears as a single central red spot with surrounding clear skin which is further surrounded by a red ring, which looks like bull’s eye. In some cases (1-17%) multiple lesions may also be seen in crops of similar size, color, and shape. Rash may commonly be seen on the thighs, groin, trunk, armpits, waistline, and behind the knees. In children scalp, hairline and face ((“slapped cheek” appearance) may also be involved. Rash is usually not itchy or painful but can be warm to the touch. In about 40-50% of patients there may be mild itching. Rash will fade gradually after 4 weeks even without treatment.
Erythema chronicum migrans is also associated with flu-like symptoms including fever, headache, fatigue, headache, sore throat, abnormal pulse, neck stiffness and pain, pain and swelling of one or more large joints, numbness or tingling sensation of hands and legs, facial paralysis, change in vision, disorientation, confusion, short-term memory loss and enlargement of lymph nodes near the tick bite.
It is very important to get early diagnosis, so if you suspect you have been to tick bite endemic areas and you started getting such rash as stated above, immediately consult your doctor or dermatologist. Early diagnosis and treatment will result in full cure for your Lyme disease. Ignoring the rash may result in more severe symptoms and complications which will develop over months or year (Acrodermatitis chronica atrophicans)
Other Conditions to Consider
There are several other conditions that may sometimes mimic such rash and includes
- Local tick bite reaction
- Insect bites
- Fixed drug reaction
What tests your doctor may perform
Laboratory tests are usually not reliable within a month after tick bite. Your doctor may perform Serology, culture and skin biopsy to confirm the disease.
What is the Treatment for Lyme disease
Oral Doxycyxline is considered as the first line of treatment for localized early Lyme disease. In pregnant women or patients with contraindication of doxycycline, amoxicillin or cefuroxime may be given. If both the medications are resistant, your doctor may prescribe azithromycin or clarithromycin. In case of late stage disease you may need to be admitted in hospital and start intravenous antibiotics.
How to prevent Lyme disease
Always avoid going to the places where tick bites are common, if you go, wear long sleeves shirts and protect your hands and legs with gloves and long socks. If you see any ticks, remove it immediately with care. You may buy insect repellents which are widely available in market. Antibiotics prophylaxis can be given for special cases if you are going in the endemic areas.
1. Fitzpatrick’s Dermatology in General Medicine