Introduction: From 1996 through 2000, we collected data on 86 patients with similar symptoms following a tick bite. The inclusion criteria were: enlarged regional lymph nodes and/or vesicular-ulcerative local reaction at the site of the tick bite.
Methods: Epidemiological and clinical data on these 86 patients were statistically analysed. All patients were tested for borrelia and 73 cases for Rickettsia slovaca antibodies by immunoblot. Fine-needle lymph node and/or skin biopsy was done in 13 patients. Gehomic PCR amplification was performed on these biopsy samples.
Results: Seventy-six patients described an "extremely big" tick, and/or recognised a Dermacentor spp. tick from a collection of several species indigenous to Hungary. The tick bite was usually (96%) located on the scalp region. The time from the recognition of the tick bite to the first symptom varied between 0 and 55 (mean nine) days. A characteristic local reaction (eschar) was seen in 70 (82%) patients. The eschar can be surrounded by a circular erythema (18 cases, 21%). The other main symptoms are the enlarged and sometimes painful lymph nodes in the region of the tick bite, characteristically in the occipital region and/or behind the sternocleidomastoideal muscle. The most frequent general symptoms were low-grade fever, fatigue, dizziness, headache, sweat, myalgia, arthralgia, and loss of appetite. Without treatment, the symptoms were seen to persist for as long as 18 months. One of the patients reported symptoms suggestive of encephalitis. The infection occurs most commonly in young children (age range: 2-57 years, mean: 12.6 years, 63% less than 10 years of age). A female predominance was registered (50/36). Doxycycline treatment can shorten the usually benign illness. R. slovaca PCR gave positive results from skin or lymph node biopsy samples in 10/13 (77%) patients.
Conclusion: We have described a new and frequent tick-borne infection, most probably caused by R. slovaca.