Abstract
We analyzed cases of tick bites that visited one dermatology clinic in Shizuoka Prefecture from 2016 to 2023. The age distribution of the 754 patients (346 males and 408 females) ranged from 0 to 97 years, with the largest number (240 cases) in their 70s. By tick species, Amblyomma testudinarium (AT) was the most common (717 cases), followed by Haemaphysalis longicornis (28 cases). The month with the highest number of cases was May (226 cases). As for the bite site, AT bites tended to be more common on the lower half of the body. Among the 717 cases of AT bites, 150 cases (20.9%) had erythema larger than 50 mm (tick-associated rash illness, TARI). ABO blood typing of each case showed no significant difference between AT bites and TARI cases. TARI cases were significantly more likely to have a history of tick bite. The success rate of tick removal methods in AT bites were significantly higher in the group using tick removal devices than in the groups using finger or tweezers. There were no cases of Japanese spotted fever or severe fever with thrombocytopenia syndrome after tick bites, suggesting that the risk of developing tick-borne infectious diseases is extremely low.
