Steere on EM - erythema migrans
From: Phyllis Mervine (pmerv_at_direcway.com)
Date: 07/29/04
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Date: 29 Jul 2004 15:21:15 -0700
The reason the rash of Lyme disease (erythema migrans) is known as a
bull's-eye rash, is because the pathognomonic (i.e. diagnostic)
lesion, described as a centrifugally expanding, red rash with a darker
or redder outer border, clearing in the center as it spreads over a
few days or weeks, resembles a bull's-eye target. Steere's description
below is consistent with the "bull's-eye" concept, especially his
mention of "several red rings... within the outside one."
This pathognomonic rash is now known only to occur in 9% of patients
who are diagnosed with Lyme disease (so presumably an even smaller
percentage of all people who have Lyme disease, since many people will
not be diagnosed unless they display this rash). Other types of rash
are more typical. Most people in the study had a uniformly red rash
around the bite area.
Steere's 25% (below) is also an underestimation, although it is
interesting that he does not attempt to correct this estimate in his
2003 letter to the New England Journal. In 1998, during the vaccine
trials, on which Steere also worked, Dennis Parenti of SmithKline
reported that only 60-65% of the volunteers who seroconverted
displayed an erythema migrans. This means at least 35-40% did not, and
likely the figure is higher, since the rash may be hidden under hair,
or otherwise not noticed. This is consistent with Burrascano, who
estimates "fewer than half" get an EM (see Burrascano Guidelines at
www.ilads.org).
Another interesting point made by Parenti based on data from the
vaccine trial was that one third of people who developed EMs did NOT
have positive blood tests. Because Parenti et al are likely to have
reflected the more stringent definition of Lyme disease prevailing in
academia, this is a significant finding which has not been published
(to my knowledge). The ILADS Guidelines state that "Diagnosis of Lyme
disease by two-tier confirmation fails to detect up to 90% of cases."
[Cameron DJ. Monitoring Lyme disease in the community – First
surveillance database sentinel health site. Proceedings of the 12th
Annual International Scientific Conference on Lyme Disease and Other
Spirochetal and Tick-Borne Disorders (1999)]. This may be closer to
the truth.
Below is an excerpt from Conn's Current Therapy 98: "LD - Method of AC
Steere"
CLINICAL MANIFESTATIONS
EARLY INFECTION: Stage 1 (Localized Infection)
After an incubation period of 3 to 32 days, EM, which occurs at the
site of the tick bite, usually begins as a red macule or papule that
expands to form a large annular lesion, most often with a bright red
outer border and partial central clearing. Because of the small size
of ixodid ticks, most patients do not remember the preceding tick
bite. The center of the lesion sometimes becomes intensely
erythematous
and indurated, vesicular or necrotic. In other instances, the
expanding lesion remains an even, intense red; several red rings
are found within the outside one; or the central area turns blue
before it clears. Although the lesion can be located anywhere,
the thigh, groin, and axilla are particularly common sites. The
lesion is warm but not often painful. Perhaps as many as 25% of
patients lack this characteristic skin manifestation of the disorder.
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