TOENAILS FALLING OFF
SYMMETRICAL LUPOID ONCHODYSTROPHY
By far, in
greyhounds, the most common reason for multiple nail loss from
multiple feet is pemphigus-aka symmetrical lupoid onchodystrophy
(SLO). In pemphigus/SLO, the nails separate at the base and come
off. You may see normal looking nails and more blood upon losing a
nail in newer cases and less blood and "funky nails" in more
chronic cases. The nails that regrow are stumpy, crumbly, and
Pemphigus/SLO as it occurs in the
greyhound involves the nails only, there are no other systemic
signs - though there may certainly be a poor appetite and/or
lethargy associated with the chronic pain. All of the greyhound
specific texts and articles I've ever read refer to this
autoimmune condition as "pemphigus." These sources include Care of
the Racing Greyhound (Blythe, Gannon, Craig), Canine Sports
Medicine & Surgery (Bloomberg, Dee, Taylor), and The Racing
Greyhound - Management, Medicine & Surgery (Herron, Gannon). On
the other hand, a biopsy submitted to any commercial lab will be
given the diagnosis of "SLO". Properly, as one of the IDEXX
pathologists explained it to me, SLO involves nails and so is the
correct histopathological diagnosis, whereas pemphigus involves
footpads and interdigital skin. So "pemphigus" vs. "SLO" is
unimportant and a matter of semantics; we are talking about the
same clinical syndrome. While toenail pemphigus/SLO is an oddball
diagnosis in other breeds, it should go straight to the top of the
list in greyhounds experiencing multiple nail loss.
While it is, of course, possible to
get secondary infections in unhealthy pemphigus nails, you cannot
resolve the problem without treating the underlying autoimmune
disorder. Too many people spend too much time and money treating
pemphigus as a "fungal" (the #1 misdiagnosis) or "bacterial"
infection with foot soaks, topicals, and expensive oral
medications. Common sense will tell you that culturing a nail as a
means of diagnosis is quite likely to yield any number of cooties
as greyhounds use their nails to walk across the (unsterile)
Unfortunately, the only way to
definitively diagnose pemphigus/SLO is by amputating the whole P3
(end toe bone, including nail, just as you declaw a cat). A
pathologist can make the diagnosis only by observing the skin/nail
junction. The appearance/course of pemphigus in greyhounds is so
classic that I feel it's a real waste of time/money, not to
mention unnecessary pain and disfigurement for the poor greyhound,
to go through this in the name of proving a diagnosis.
At Arizona Adopt A Greyhound, when we see one of these, the adopter gets a bottle of 4 mg chlorphenerimine tablets and a bottle of 5 mg prednisone tablets for treatment as outlined in Care of the Racing Greyhound. I do alter the dose at the end so that the dog winds up on prednisone every other day, which is healthier on the body.
Once healthy nails have regrown, it may
be possible to wean the dog off of prednisone entirely. Though it
takes 4-5 months for new nails to regrow, often there is a
dramatic improvement in comfort within the first few weeks of
treatment. My experience has been that the sooner you get on top
of these, the better the chance for regrowth of normal nails.
Chronic untreated pemphigus greyhounds will always have crumbly
stumpy nails, but at least treatment even at that point will stop
them from continuing to lose nails.
It is also worth checking thyroid levels and supplementing
greyhounds that are unequivocally low. Many if not most greyhounds
have marginally low thyroid levels normally - I certainly don't
advocate putting all of these on Soloxine.
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