Springtime is tick time
April 27, 2017
Oh, the majesty of spring’s rejuvenation — a bloom’s aroma, opening day’s first pitch, and romance in the air. For dermatologists, no one will write a sonnet devoted to rhus dermatitis, polymorphous light eruption, or Rocky Mountain Spotted Fever (RMSF)!
Springtime is also tick time. According to Buckingham (1), there are 10 things clinicians should know about ticks in the USA:
Patients are exposed to ticks more frequently than you might think. (Tick bites may occur in urban areas and often go unnoticed. Only about half of those with RMSF will report a tick bite.)
Geography is important. (Specific tick-borne infections occur only in regions where their associated tick vectors are found. Knowledge of the patient’s locale and travel history should allow clinicians to determine which tick-borne illnesses are likely, or even possible. RMSF has been reported in virtually every area of the United States in part because at least 3 different tick vectors have been implicated in its transmission.)
Tick-borne infections are seasonal — except when they’re not. (The vast majority of tick-borne infections are reported between April and October. It should be remembered, however, that 3% of RMSF cases reported to CDC from 1997 to 2002 occurred between the months of December and February, from regions as far north as New England.)
Tick-borne infections are easily confused with other childhood illnesses. (Often children present with various nonspecific signs and symptoms such as fever, malaise, headache, nausea, vomiting, and myalgias. Thus, it is not surprising that most patients with tick-borne infections are first suspected as having more common childhood illnesses, such as gastroenteritis, streptococcal pharyngitis, or viral syndromes. This is especially problematic for RMSF, as the purportedly “classic triad” of fever, rash, and headache is present in fewer than 60% of patients with laboratory-confirmed disease.)
Therapy should not be delayed. (The most consistently identified risk factor for mortality in RMSF is the delayed initiation of appropriate antimicrobial therapy.)
Diagnoses are presumptive — and unfortunately, often delayed. (Although both patients and physicians crave diagnostic certainty, tick-borne infections should be diagnosed presumptively, based on patients’ clinical findings and epidemiologic histories.)
Concerns over the toxicity of doxycycline in young children are unfounded. (Doxycycline is the drug of choice for tick-borne rickettsial illnesses, and this is true for both adults and children. Don’t worry about staining a child’s teeth!)
“Chronic Lyme disease” is not a real thing. (According to Buckingham, “To be sure, some patients, after completing therapy for Lyme disease, continue to experience persistent nonspecific symptoms, such as fatigue, musculoskeletal pain, and difficulty with concentration. However, there is no objective evidence to suggest that persistent Borrelia burgdorferi infection is responsible for these symptoms, which are also quite common in the general population.”)
Prevention relies on simple measures. (Prevention relies on avoidance of tick bites and the prompt removal of attached ticks. During the spring and summer, it is advisable to examine persons and pets on a daily basis for attached ticks for those who have spent time outdoors.)
When used properly, DEET is safe and effective. (Insect repellents that contain N, N-diethyl-meta-toluamide (DEET), in concentrations of 10%–30%, are most effective for the prevention of tick and insect bites.)
Tull et al performed a retrospective review of 3,912 consultations were conducted in the dermatology service over 10 years. Six patients with RMSF, ranging in age from 22 months to 10 years (mean 5.1 years), were evaluated during April, May, and June. All preconsultation diagnoses included RMSF in the differential diagnosis. All patients underwent skin biopsies, and a culture was obtained in one case. Fifty percent of patients died within 4 days of hospitalization. Variables associated with mortality from RMSF are delayed diagnosis and initiation of antirickettsial therapy. An important point is raised in the discussion: Up to 95% of children with RMSF develop a rash within the first 2 days of illness, compared with 80% of adults developing a rash within 4 days of illness. The authors emphasize that physicians should consider RMSF in children presenting with fever and rash during the summer months (2).
I was a consultant on a heartbreaking, fatal case of RMSF in an HIV patient, where the presumptive diagnosis was secondary syphilis. The patient’s course is detailed with the frank honesty of his infectious disease physician’s rationale and perspective. Mark DeNubile wrote this paper as a “mea culpa” confessional describing where his diagnostic acumen went awry (3). It is must reading for any physician (realistically every physician) who has lost a patient due to reaching incorrect conclusions based on the data before them. None of us take solace in knowing that this unfortunate outcome happens more frequently than anyone would like. We all need to think about ticks and tick-borne illness in the spring — so that every human being can enjoy springtime’s wonders in good health.
1. Buckingham SC. Tick-borne diseases of the USA: Ten things clinicians should know. J Infect 2015; 71 Suppl 1: S88-96.
2. Tull R, et al. Retrospective study of Rocky Mountain Spotted Fever in children. Pediatr Dermatol 2017; 34: 119-23.
3. DiNubile MJ. Reliving a nightmare: A hard (and tragic) lesson in humility. Clin Infect Dis 1996; 23: 160-5.
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