Procedures for tick bites 
RECOMMENDED PROCEDURES 
FOR TICK BITES IN A LYME BORRELIOSIS 
ENDEMIC AREA 
F. Strle 
ABSTRACT 
Ticks transmit causative agents of several diseases; however, the most-common disease in many parts of the 
northern hemisphere is Lyme Borreliosis. An active search for possibly attached ticks (after potential exposure 
to an appropriate environment) is quite important for preventing the disease because it enables early 
detachment. 
Recommended procedures after a tick bite in a Lyme Borreliosis endemic region include early removal of 
the attached tick, disinfection of the site of the tick bite, the policy of wait and watch for the possible 
appearance of Lyme Borreliosis manifestation(s) and advice on early treatment of the possible signs or 
symptoms of Lyme Borreliosis. 
The effectiveness of antibiotics for preventing Lyme Borreliosis has not been unequivocally praven. Even 
if it was determined, severa! questions concerning the rationality of such preventive usage of antibiotics 
remain to be answered. 
KEY WORDS 
Lyme Borreliosis, prevention, procedures after tick bites, removal of an attached tick, 
preventive usage of antibiotics 
INTRODUCTION 
Ticks transmit causative agents of several diseases; 
however, the most common human illness in many 
parts of the northern hemisphere is Lyme Borreliosis 
(LB) (1,2). 
Its clinical course is difficult to predict and when 
the illness assumes a chronic form, it can notably 
deteriorate the patient's quality of life. The risk of 
late sequelae is reduced, though not completely 
eliminated, by initiating proper therapy in early 
acta dennatovenerologica A.P.A. Vol 5, 96, No 3-4 
stages of the disease (3). At present, most efforts 
are directed to the prevention of infection by effective 
immunization and to non-specific protective measures. 
In the recent years, people have been increasingly 
afraid of being exposed to a tick and the associated 
risk of Borrelia burgdorferi (Bb) infection and some 
individuals even panic when bitten by a tick. T.hus, 
it is important to have simple and precise advice 
on what can be done and what should be done 
following a tick bite. 
173 
Procedures f or tick bites 
RECOMMENDED PROCEDURES 
AFTER TICK BITES 
ACTIVE SEARCH 
FOR POSSIBL Y AITACHED TICKS 
There is not doubt that active search far a tick 
which may be attached to a person is important 
because it enables early removal. People should be 
encouraged to actively check themselves and their 
clothing after any potential exposure to ticks. 
REMOVAL OF AITACHED TICKS 
Important questions about removal are: when and 
how to do it. 
The answer to the question „when?" is as soon as 
possible. It is well known that even if a tick is 
infected, transmission does not invariably occur after 
each bite. One of the reasons is that the tick has 
not been attached long enough far bacteria to be 
successfully transmitted to the feeding site ( 4,5). In 
questing ticks borreliae are usually limited to their 
midgut (6-8); far transmission the spirochetes should 
disseminate and arrive in salivary glands (8-10). 
Experiments on animals have stressed the importance 
of early removal of ticks: transmission occurred only 
exceptionally when the tick was removed within 48 
hours of the bite, while longer attachment times 
were associated with a much higher probability of 
transmission ( 4,5). 
However, the results of animal experiments cannot 
be automatically applied to man. Furthermore, data 
from patients with erythema migrans (EM) suggests 
that some of them developed skin lesions even after 
a very short tick attacbment tirne. Similar data was 
also faund at Lyme Borreliosis Outpatient Clinic in 
Ljubljana wbere 892 adult patients witb typical EM 
were diagnosed and registered by faur pbysicians in 
1993 (11). All tbe patients were asked to estimate 
tbe duration of tbe tick attacbment. One tbird (212/ 
654) of tbe patients witb a tick bite at tbe site of 
later EM stated tbat tbey were able to accurately 
assess the maximum possible duration of the tick 
attachment. These patients were predominantly indoor 
persons who remembered tbe day and bour wben 
tbey went out (usually far a walk in tbe forest) and 
tbe tirne wben tbey returned and discovered an 
attacbed tick. Nearly one tbird of tbese 212 patients 
reported the duration of attacbment to be up to 12 
bours and more than two tbirds assessed tbis tirne 
to be 24 bours or less (11) . 
174 
Tbese results seem to conflict witb the findings of 
experiments on animals conducted in the USA in 
wbicb transmission did not take place during tbe 
first 24 bours of attacbment (4). Wben interpreting 
tbis contradiction it sbould be stressed tbat tbe tirne 
required for transmission from a tick vector to a 
bost may be different far bumans than for laboratory 
bosts (bamsters) and natural animal bosts (wbite-
footed mice ). Moreover, animal experiments were 
carried out witb Ixodes scapularis (4,5,12) and not 
witb /. ricinus ticks wbicb are present in Europe (8) . 
Tbe epidemiological data presented bere concerning 
I. ricinus complies witb the observations of Lebet 
and Gern, wbo described the presence of Bb in 
salivary glands of a relatively bigh percentage (11 % ) 
of l. ricinus nympbs before tbe blood meal (13). 
Tbis suggests tbat tbe transmission of spirocbetes by 
tbese ticks may occur earlier tban wbat was described 
for l. scapularis. 
A plausible explanation for tbe disseminated infection 
in ticks and tbe accelerated transmission of spirocbetes 
to a bost is antecedent partial feeding of ticks (14). 
Tbe results tbat were obtained in patients with EM 
do not negate tbe possibility that the proportion of 
exposed population wbo develop an EM lesion is 
lower or even mucb lower in persons who carry tbe 
infested tick far shorter durations (i.e. 24 bours or 
less); bowever, according to tbis data, tbere is no 
„safe" first 24-bour period of tick attacbment. It 
stili remains to be elucidated as to wby and bow 
often this kind of early transmission occurs. 
Despite ali tbe above-mentioned reservations, prompt 
removal of tbe tick remains a simple and, probably 
in most cases, an effective way of preventing Bb 
infection and LB in humans. 
Daily inspections for attached ticks sbould be a 
regular routine in endemic regions and prompt 
removal of attacbed ticks cannot be emphasized 
enougb (15). 
Tbe next question is „bow?". 
Attacbed ticks must be removed immediately witb 
fine forceps. 
A variety of tick removal products are now available 
for tbis purpose, but actually notbing more complicated 
tban forceps witb sbarp tips is necessary (15,16). 
The tick sbould be grasped as close to tbe point 
of attachment as possible and pulled witb a steady 
motion directly away from tbe skin until removed 
(15). 
Some people put a drop of oil on tbe "!ttacbed 
tick - after a few minutes it will fall away by itself 
witbout any traction. However, tbis metbod is only 
effective in cases when it was attacbed for a sbort 
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Procedures f or tick bites 
Table. Controlled tria/s of antibiotic therapy to prevent Lyme Borreliosis after a tick bite (17,19,20). 
Costello 
Shapiro 
Agre 
1989 
1992 
1993 
Fisher exact test (2-tailed): p = 0.0593730 
period of tirne, that is, when it was attached only 
superficially; when it is embedded in the skin for a 
longer period of tirne a drop of oil will not be of 
any help. There is a fear that manipulating an 
attached infected tick might increase the chances 
for transmission of the causative agent to the host. 
If this were true, it would be logical to expect that 
it would be more effective when it occurs through 
vomiting or defecation and not through transmission 
via salivary glands. 
Often, especially with adult ticks, some of the 
mouthparts (hypostome) remain in the skin. Complete 
removal is not necessary to prevent Bb infection 
(15). However, the embedded parts need to be 
treated as foreign body. 
LOCAL DISINFECTION OF SKIN AT THE 
BITE SITE 
As with any wound, it is necessary to disinfect the 
area. However, it would be beneficial to have a 
disinfecting agent, which used topically at the site 
of a tick bite, would have borrelicidal effects on 
borreliae already present in skin. Unfortunately, I 
am not aware of any such agent. 
Wait and watch for the eventual appearance of 
Lb manifestation(s) 
In addition to early tick removal, some authors 
recommend the use of antibiotic prophylaxis. Several 
reports on this issue appeared in literature mostly 
published after 1992 (17-20). Some authors tend to 
use preventive antibiotic treatment for patients with 
a history of a recent tick bite (21-23), other authors 
have many reservations against empirical antibiotic 
prophylaxis (17,19,20,24-26), while others maintain 
that antibiotics should only be given to patients with 
a high chance of infection, i.e. when chances to 
acta dennatovenerologi,ca A.P A . Vol 5, 96, No 3-4 
0/27 
0/192 
0/89 
0/308 
1/29 
2/173 
1/90 
4/292 
(3.4%) 
(1.2%) 
(1.1%) 
(1.4%) 
develop LB after a tick bite are greater than 3.6% 
(18,27), in the event that examination for borreliae 
in tick is positive (28) or after sufficiently long 
period of attachment of the tick (29). 
All these views, however, are based on the 
presumption that antibiotics administered after a 
tick bite can effectively prevent Bb infection. 
It would be reasonable to suppose that antibiotics, 
which are successfully used for treatment of LB, 
can be equally effective for preventing Bb infection. 
However, generalizing about the efficacy of a treatment 
modality may be misleading, as illustrated by the 
example of Rickettsia rickettsii infection: therapy with 
tetracycline for Rocky Mountain spotted fever may 
be potentially life-saving, yet in asymptomatic 
individuals with a history of tick bite, tetracycline 
can at the very best delay rather than prevent the 
onset of the disease (30). 
In controlled trials of antibiotic therapy to prevent 
LB after a tick bite (data from the USA) (17,19,20), 
none of the 308 patients that were given pheno-
xymethylpenicillin, doxycycline or amoxicillin developed 
LB while in the control groups in 4/292 manifestations 
of LB appeared (see Table). These numbers are not 
high enough to prove a significant statistical difference. 
In addition, if the preventive antibiotic usage really 
is effective, we neither know which antibiotic is the 
best choice for prophylaxis nor the dosage and 
duration of treatment. 
In studies presented on the Table phenoxymethyl-
penicillin (17,20), tetracycline (20) and amoxicillin 
(19) were used for 10 days in a dosage that is 
usually applied for the treatment of EM. However, 
as shown in the study by Shapiro and coworkers, 
compliance to the prescribed regimen may be a 
substantial problem (19). 
Even if we presume that antibiotics can successfully 
prevent the disease, it is highly debatable whether 
175 
Procedures f or tick bites 
this prophylaxis is rational. The obseived discrepancy 
in recommendations provided in the literature is 
mainly due to inadequate information about the 
factors involved in the transmission and development 
of the disease. 
Accurate data is needed regarding the proportion 
of infected ticks in individual geographic areas as 
well as regarding the incidence of infection following 
a (infected) tick bite and the rate of asymptomatic 
infections. The latter is estimated at 80% in Europe 
(31,32) and approximately 50% in the USA (33,34). 
It should be emphasized that it is nearly impossible 
to know the tick infection rate for all individual 
geographic regions and that data on the chances of 
infection after a bite by a borrelia-infested tick is 
sparse (17,19) and may theoretically range from O 
( as in a tick with small number of spirochetes in 
the midgut which was attached for a short tirne) to 
100%. 
Thus, we cannot accurately determine the chances 
of developing LB after a single tick bite. Additional 
studies will be needed to answer this question more 
precisely. Yet, it seems that on average chances of 
developing LB after a single tick bite are low and 
may only rarely surmount 3.6%, i.e. the percentage 
found in a mathematical model to be a limit above 
which preventive treatment with doxycycline (100 
mg b.i.d. for 10 days) in all persons with a tick bite 
is cost effective (18). Even lower chances (1 %-
3.6%) are probably achieved only rarely. 
When weighing the pros and cons of the use of 
antibiotic prophylaxis in patients bitten by a tick, it 
should be kept in mind that, in addition to being 
potentially harmful to the patient, overuse of antibiotics 
also has general untoward effects, such as selection 
of resistant bacteria. 
EARL Y TREATMENT 
A prerequisite for early treatment is early 
recognition, that is, a timely diagnosis. 
It is relatively easy to diagnose a typical EM 
lesion, but often not so simple to recognize other 
manifestation(s) of LB without previous EM. 
There may be some difficulties in interpreting the 
small redness at the site of a tick bite: this may be 
an early EM lesi on or unspecific ( allergic or toxic) 
reaction at the site of the tick bite. The latter 
usually develops at the tirne when a tick is still in 
the skin or in the first 24 hours after removal of 
the tick, while in EM a free interval from the tick 
bite to the appearance of skin redness of at least 
severa! days is typical. 
It is not necessary to administer an antibiotic to 
a person with small redness on the skin in the 
vicinity of a tick bite which was removed one day 
ago, but serious thought should be given to EM 
and antibiotic treatment in a patient with a skin 
redness of the same diameter if the skin lesion 
appears one week after the bite. 
CONCLUSIONS 
Attached ticks should be removed promptly. 
The efficacy of antibiotics in preventing Bb infection 
and the onset of LB has not yet been unequivocally 
confirmed. Even if antibiotic prophylaxis proved 
efficacious, it remains to be assessed whether it is 
rational or not. Although the available data does 
not allow us to draw any definitive conclusions, it 
seems to speak against, rather than in favour of, 
general antibiotic prophylaxis following a tick bite. 
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AUTHOR'S ADDRESS 
Franc Strle MD, PhD, professor of infectious diseases, Department of Infectious Diseases, University 
Medica! Center Ljubljana, Japljeva 2, 1525 Ljubljana, Slovenia 
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