02/29/2024    Bryan C. Markinson, DPM

RE: FL Podiatrist published in Journal of Fungi (William Scherer, DPM)

Dr. Scherer's article, which I have not yet read,
as summarized in PM News, reported a 59.4%
positivity rate for clinically diagnosed
onychomycosis. In this very large sample of cases,
I am sure there are variables that were very
difficult to control. For example, specimen
collection techniques are so varied that I am
certain this was a factor in the end results.
However, I fully understand and support
wholeheartedly the point of the study...it's NOT
all onychomycosis.

Laboratories publicly promising that they will find
it and the expectations from practitioners that
they must find it has not helped our collective
credibility.

I have long listened to the proclamations of large
numbers of our colleagues that "we know
onychomycosis when we see it," as stated by Drs.
Udell and Roth, in their comments on this issue. I
have large numbers of referred "recalcitrant
onychomycosis" cases that prove the exact opposite.
For the record, the 59.4 percent number, assuming
it's just toenails, and mostly hallux toenails, is
somewhat lower than what I would expect. In my own
practice, with me the only provider, and the use of
one hospital dermatopathology laboratory for PAS
staining and one mycology laboratory for fungal
culture, I have a positivity rate after clinical
diagnosis of about 85%. I only do this testing for
patients who I intend to treat, and that is mostly
with oral agents. I do not choose to participate in
the arguments regarding costs of testing, just on
the necessity of it.

There is no dermatology, mycology, or infectious
disease expert with any notoriety on the planet
that endorses diagnosing and treating onychomycosis
without laboratory confirmation. An article a few
years ago on cost containment in the dermatology
literature recommending NOT testing was quickly and
summarily dismissed by the dermatology profession.

Consider an oncology surgeon aspirating fluid from
a breast tumor, holding it up to the light, and
discarding it, saying, "I know cancer when I see
it." Well, the same approach to onychomycosis
where treatment (beyond mechanical) will be
initiated is subpar, below standard, and may even
be negligent. I reviewed a case where a patient
died waiting for a liver transplant due to an
idiosyncratic fulminant hepatic failure after
terbinafine therapy was started. Although it would
have happened regardless, the case went to large
settlement specifically because of lack of
laboratory confirmation that the patient ever had
onychomycosis. But for the relative seriousness of
a cancer diagnosis versus onychomycosis, the
departure from good and accepted practice is
exactly the same.

A quick reminder to those who know onychomycosis
when they see it.....the FDA says it’s not
onychomycosis until it looks like it AND can be
grown in culture. The FDA also says it’s not cured
until there is no clinical evidence and there is no
growth on culture.

Bryan C. Markinson, DPM, NY, NY

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