Pemphigus Vulgaris

Introduction

Pemphigus vulgaris is an autoimmune disease of the skin, which is very rare in all animals. The autoantigen responsible for causing disease dictates where the lesions will be seen, as this is where the inflammatory response to the autoantigen will occur.
Pemphigus vulgaris causes intraepidermal vesicular dermatitis, where an autoanitbody to cadherin adhesion molecules called desmogleins, in the epidermis causes seperation of keratinocytes (acantholysis). This leads to a blister or pustule forming. In Pemphigus vulgaris, there is subrabasilar clefting as a consequence of acantholysis.
The disease is characterised by vesicles (and bulla), erosions and ulcers. The oral cavity is affected in around 90% of cases and the ears, mucocutaneous junction, groin, axilla and claws are also affected.

Signalment

These disease can occur in any animal, though is most commonly seen in the dog. There are no breed predilections. It is thought that females are more prone to autoimmune diseases than males. Autoimmune diseases tend to first present when the animal is around 1- 3 years of age.

Clinical Signs

Vesicles and erosions and ulcers will be present in some or all of the areas mentioned above. There will likely be secondary bacterial infection, which may complicate clinical signs and cause pustules, erythrema and pruritus. If the disease is very severe, pyrexia, lethargy and depression may also be seen.

Diagnosis

History and clinical signs may add this disease to the differential list, but many other diseases will need to be eliminated first, such as drug reactions, systemic lupus erythrematosus and bacterial diseases (if secondary bacterial infection is present).
A biopsy should be taken and will show some inflammatory cells and rows of basal cells forming base of blister, with a suprabasilar split. These signs are indicative of the disease.

Treatment

The disease is difficult to treat and often aggressive therapy is required. Often high doses of immunosuppressive drugs such as systemic glucocorticoids will be required, but this can affect the general health of the animal, so compromising decisions have to be made.

Prognosis

Guarded.

References

Blood, D.C. and Studdert, V. P. (1999) Saunders Comprehensive Veterinary Dictionary (2nd Edition) Elsevier Science Bond, R. (2008) Veterinary Dermatology Study Guide, Royal Veterinary College Foster, A, and Foll, C. (2003) BSAVA small animal dermatology (second edition), British Small Animal Veterinary Association Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition), Merial