Nodular Necrobiosis

(Equine Eosinophilic Granuloma)

One to several firm non-painful dermal nodules, usually ovoid, about 2 cm in diameter and slightly elevated occurring on the neck, withers and back associated with degeneration of collagen. The hair over them is undamaged and their cause is unknown but it is probably a hypersensitivity reaction. Insect bites have been suggested but not substantiated. Horses with multiple lesions may be treated with oral prednisone or prednisolone or sublesional corticosteroid injections. Horses with recurrent lesions, an intradermal allergy test is recommended. Surgical removal may be advised and topical therapy is of no value.

- Veterinary Notes for Horse Owners

- Merck Veterinary Manual

Matitojo Sherdan's Case

'Legs' was started under saddle in 2000 at the age of three. Shortly afterwards he developed a small lump on his back which just looked like a mozzie bite. A few more came up in the weeks following. I was originally rubbing Prednoderm on them and they seemed to disappear, but after a short time they came up again and began to cluster in a group forming one lump. As they were causing no pain or discomfort we just continued on as they were not very obvious to the eye.

In 2001, during a vet/chiro visit, it was suggested I obtain a strong cortisone cream (Ilium Neocort) as it was possible the cortisone in the original application of Prednoderm may have helped initially. In the end I never used the cream as our local vet felt it probably wouldn't help much and it would be best to leave it alone. He felt the only option wouldbe to cut the lump out, but he preferred not to take this course of action given it was more than likely the lump would simply recur.

By September, 2002 the lump was bigger, probably 3-4 cm in diameter and around 1 cm high. While unsaddling after riding one day, I noticed it had burst open in a small area, leaving a very small hole. The hole was discharging a little fluid which contained some yellowish, hard, rubber-like fibre. The vet was called and he explained Legs' condition as 'Nodular Necrobiosis'. He removed the dead fibrous tissue from the wound and hoped that once it had healed there would be no recurrence. However, a few weeks later the lump started growing quite quickly in size again, to where it is today wich is about 8 cm in diameter and around 2 cm high.

Legs and I do a lot of showing and dressage and invariably the judges comment on his lump, asking whether it affects him under saddle. I can only answer that it doesn't seem to. Our vet/chiro cannot understand how it doesn't affect him though, but he has never shown any pain in the area or adverse reaction to being ridden. For we humans, it would be like having a big stone in our shoe! We came to the conclusion that because my saddle is a 'cair' one, it could compensate for it.....we think!

Up until recently, I was never seriously concerned about the lump. Although it had increased in size over time, Legs showed no soreness and continued to perform beautifully under saddle.

In June of this year we received a nasty surprise. After Legs was clipped we discovered about 6 smaller lumps not far

from the original one, plus a couple on his wither with several more in the middle of his back on on the other side of his

body. The vet was amazed to see how they had come up. He prescribed Preddy Granules (Prednisolone) to treat the

lumps and I was to let him know how Legs was going after 14 days. After 2 days I noticed a big difference, the lumps

had decreased in size significantly and they remained that way for a week. Given the positive early effect of the treatment,

the vet suggested we keep going for a further 14 days and do another reassessment.

However, shortly after Legs started the second lot of granules all the lumps popped up again and there were more and

more arising each day. There would have been at least 20 to 30 on each side of his body. The Preddy granules now

appeared to be making things worse. During this time Legs was consistently working under saddle, but as there were

so many more lumps appearing, I eventually had to stop riding him in case it was aggravating the problem. It was time

to try and find out the cause, whatever that may be!!

A biopsy was done to confirm Legs condition and also to determine whether there was infection present or something else

entirely going on. We were also hoping to find a reason for his adverse reaction to the cortisone, but nothing showed up other

than the original diagnosis of Nodular Necrobiosis.

As well as the biopsy, blood was taken for an allergy test, but the results were disappointing as nothing conclusive stood out.

The allergy test revealed minor allergies to a few different weeds, grasses and fungi - the highest being ryegrass. Trees he tested

positive to were cottonwood, willow and casuarina and he also showed positive to corn, clover mix and oats and is borderline to

barley. Other irritants include a few different insects, pollens, cotton and cedar shavings. We have removed the controllable

items in his environment in the hope that one of them may be a possible cause.

After the biopsy Legs was taken off the Preddy Granules as they were obviously not achieving a result. Since then, the lumps

have settled down; they have ceased multiplying and have reduced in size and most days are quite flat. They do seem

to go up and down over short periods of time and unfortunately the reason is unknown. I have since stopped using a cotton

saddleblanket on him, replacing it with a pure wool numnah and the lumps appear to have 'settled'.

The next step is to use corticosteroid injections into some of the bigger lesions, but as the granules caused such an adverse

reaction we have decided to try a holistic approach first. I have contacted a holistic practitioner who has apparently treated the

condition using a herbal remedy. After speaking to one particular practitioner, it was their feeling that '"Nodular Necrobiosis are

often caused by a combination of toxicity and a weak lymphatic system so that toxins accumulate easily instead of being

dispersed in the normal way by lymphatics. So the lumps are like little cysts. A cyst is the body's way of isolating toxins it

cannot disperse in the normal way".

Over the past few weeks the smaller lumps virtually disappeared and the main large lump seemed to have 'softened' in that it

has become a little bit flatter. However, just recently, (September, 2004) they have all come up again, just as ferociously as

before so we are all still sitting here scratching our heads!!!

If anyone has had experience with Nodular Necrobiosis and has any information, please feel free to contact us.

The lumps in June, 2004 following clipping