Pemphigus in Cats

Pemphigus foliaceous in Birman

Question: Dear Dr. Michael,

My 8 year old Birman male cat has just been diagnosed with Pemphigus Foliaceous. He has constant infections of the toes, has acne around his mouth and nasal passage, and some inflammation around his penis.

I cannot find a reference to this illness anywhere, and apart from treatment with steroids, I cannot find out what this illness is. Could you please explain what this is, is there any other recommended treatment and what the long term prognosis would be.

Thank you so much, Jane

Answer: Jane-

Pemphigus foliaceous is an uncommon immune mediated skin disease that can occur in either dogs or cats. The symptoms are pretty much what you have described, sores that form around areas in which normal skin meets specialized skin. Most commonly this includes the face, feet, rectal, inguinal and genital regions. Cats often have irritation around their nipples. In dogs and cats this condition usually has pustules and skin crusts or ulcerations rather than blisters, as is seen in humans. There may be some waxing and waning over the course of these disease but in general it is a lifelong problem. I do not think that there are any known predisposing causes (except possibly food allergies as discussed below). I think that this condition is more common in Siamese and other oriental breed cats but I'm not sure that is true.

Skin biopsy is necessary to diagnose pemphigus with certainty and sometimes special fixatives have to be use (Michel's fixative).

Pemphigus foliaceus sometimes responds to topical corticosteroids, especially when the number of sore areas is small. More commonly systemic treatment is required, though. Oral corticosteroids, usually prednisone, are used most commonly. If corticosteroids are not sufficient alone, there are other therapies. Chlorambucil (Leukeran Rx) can added to prednisone usage. The dose for chlorambucil when used with prednisone for pemphigus is 0.2mg/kg every 24 to 48 hours (Helton-Rhodes 1994). Some vets use azathioprine (Imuran Rx) but there are reports of this causing severe side effects, including death, in cats, so it should be used cautiously or as a last resort. Chrysotherapy (gold salt therapy) has been used in cats and is reported to work well.

Some people feel that food allergies may play a role in pemphigus diseases in cats and there probably isn't any reason not to try a food trial to rule this out. Vitamin E supplementation may be helpful.

In our practice we have had pretty good luck with prednisone but we had one cat who did not respond to prednisone or to prednisone/chlorambucil combinations. The owners elected to euthanize this cat without pursuing gold salt therapy. So far, that is the only cat I can remember that didn't respond to treatment and I suppose it might have responded to gold salt therapy, although that wasn't tried.

I hope this helps some.

Mike Richards, DVM

11/15/2001

Pemphigus

Question: Dear Dr. Richards, My girlfriend has recently had one of her cats diagnosed with phemphigus folliaceous based on clinical exam and skin biopsy. I am an orthopedic surgeon and have some experience with patients with related auto-immune diseases. Her cat seems to have responded well to steroids (high dose from what I would see in people) and my question is several part. 1) Do steriods have all the negative side effects in cats as people. e.g. osteoporosis, skin fragility, muscle atrophy, ect? 2) She is going to begin gold salt rx. This has been used in the past with human rheumotoids but has falling into some disuse lately with more emphasis on the "disease modifying agents" such as methotrexate, imuran, and now arava. Are any of these "dma" agents being used in cats for treatment of this disease? ps. I can't tell how excited we are about your web site. She has three cats and I have six. As I'm sure with most subscribers, they are more like children than pets so it's great to see someone giving them serious consideration.

Answer: J.

Cats are much less sensitive to side effects from corticosteroids than other animals (and I assume people, too). I am not at all sure why this is the case. But they do still experience all the same effects, just less severely or requiring much higher dosages to cause them.

There is an article on using gold salts in cats for pemphigus that I found in one of the databases. I have been under the impression that reaction to gold salts was more common in cats than in dogs (and there are several reports of deaths associated with gold salt therapy in dogs) but there is no mention of this in the report. I think that it is recommended that a small test dose be used prior to initiating therapy, in order to evaluate the potential for adverse reactions.

Chlorambucil is recommended as an adjunct to prednisone by several veterinary dermatologists. The protocol for this is in Kirk's Current Veterinary Therapy XII but that book is at my office and I am at home. Your vet would probably have this reference, though. I can't recall any mention of methotrexate use. Azathioprine (Imuran Rx) has been used in cats and can also be used in conjunction with corticosteroids, if necessary. Leflunomide (Arava Rx) has been used in dogs but I have not seen any reports of its use in cats. Due to the numerous oddities in cat's ability to process medications it is best to wait until someone else tries things first unless you get really desperate.

We have had pretty good luck treating pemphigus in cats with prednisone, alone. We have tried prednisone and azathioprine in at least one patient who was refractory to prednisone alone and it seemed to help. Hopefully you will experience similar success.

Mike Richards, DVM