Laurie's Blogs.

Quite some time ago I received a question about metal reactivity in dogs.  It’s taken me a while, but I decided to look through the literature to see what I could find.  So here we go!

Kimura T (2007) described cases of contact hypersensitivity to stainless-steel cages (chromium metal) in Mexican hairless dogs.    Macroscopically, early lesions were macules and/or papules and they gradually progressed to severe inflammatory dermatitis over the dorsum. In the chronic phase, lichenification, kyperkeratosis, hyperpigmentation, dryness, scaliness, and fissuring were observed in the skin. Avoidance of contact with the stainless-steel cages resulted in clinical improvement.1

Other papers and online sources point to potential allergies to nickel.  In that, the coating of bone plates2 or external hardware (i.e. the buckle on a collar)3 can minimize soft tissue reactivity caused by exposure to nickel.  Stainless steel products (including dog dishes and collars) often contain nickel, whereas surgical stainless steel products are reported to contain negligible amounts of nickel.4

Many people are likely familiar with the concern about osteosarcoma in dogs following tibial plateau leveling surgeries. 5, 6, 7, 8 The argument used to be that large-breed dogs were more prone to osteosarcoma and that they may have developed the condition regardless of the TPLO implant.  However, newer studies are showing a direct correlation.8 Is this a metal reaction?  That part is not entirely clear.

For the most part, my Pubmed search was disappointing on this topic.  Searching for metal reaction, metal hypersensitivity, implant hypersensivity, metal allergy, metallurgic, implant allergy, and so on, yielded very few studies that answered the question about whether dogs can have a metal reaction / allergy to implants (and what that might look like).

I do recall a dog I saw at a surgical centre back when I was shadowing a surgeon there many years ago.  It was a little white French Bulldog.  She had had a tibial tuberosity transposition for a medial patellar luxation.  I was with the surgeon at the 6 or 8 week follow up.  The little dog wasn’t using the leg, and the surgeon decided to do an x-ray.  It was the craziest thing I had seen.  There was no bone around the pin.  It appeared to be eaten away!!  The surgeon was baffled.  (I don’t even remember what (if anything) he recommended.)  I do remember that we saw the dog a year later in my clinic. (Talk about slow to refer!!!)   She still wasn’t using the leg, but at this point, she had also lost motor control and reflexes to her lower leg (i.e. a peripheral nerve lesion).  As I can best remember, finances were an issue, and with the history of the problem, we didn’t think we could make a difference, so I don’t think we saw her again after that consult.  Anyways, the point of the story being, that for all intents and purposes, THAT looked like a reaction, hypersensitivity, or allergy to the metal pin that had been put insitu.  It’s a case I’ve never forgotten!

I wish I had more to share and found more research to illuminate this issue.  However, my search left me wanting!  My thoughts are that it’s quite possible that dogs can have reactions to metal.  Why not?  I do think that the correlation with TPLO plates and subsequent proximal tibial osteosarcomas are a result of hypersensitivity. (My opinion anyways.)  So, it might be something to consider in your canine patients if you are asked about the subject or if you are trying to deduce a problem in which a metal reactivity could be the source of an issue.  Food for thought!

References:

1.Kimura T.  Contact Hypersensitivity to Stainless Steel Cages (Chromium Metal) in Hairless Descendants of Mexican Hairless Dogs. Environ Toxicol. 2007, 22 (2), 176-84.

2.Ozeki K, Yuhta T, Aoki H, Fukui Y. Inhibition of Ni release from NiTi alloy by hydroxyapatite, alumina, and titanium sputtered coatings. Biomed Mater Eng. 2003;13(3):271–279.

3.Metal Allergies in Dogs.  http://mylifewithflyballdogs.blogspot.com/2013/03/metal-allergies-in-dogs.html.  Accessed January 26, 2020.

4.Nickel Allergies in Dogs.  https://wagwalking.com/condition/nickel-allergies. Accessed January 26, 2020.

5.Boudrieau RJ, McCarthy RJ, Sisson RD Jr. Sarcoma of the proximal portion of the tibia in a dog 5.5 years after tibial plateau leveling osteotomy. J Am Vet Med Assoc. 2005;227(10):1613–1591.

6.Atherton MJ, Arthurs G. Osteosarcoma of the tibia 6 years after tibial plateau leveling osteotomy. J Am Anim Hosp Assoc. 2012;48(3):188–193. 

7.Selmic LE, Ryan SD, Boston SE, et al. Osteosarcoma following tibial plateau leveling osteotomy in dogs: 29 cases (1997-2011). J Am Vet Med Assoc. 2014;244(9):1053–1059. doi:10.2460/javma.244.9.1053

8.Selmic LE, Ryan SD, Ruple A, Pass WE, Withrow SJ. Association of tibial plateau leveling osteotomy with proximal tibial osteosarcoma in dogs. J Am Vet Med Assoc. 2018;253(6):752–756.