What are pemphigus?
Pemphigus are a group of autoimmune skin diseases in which the dog's system attacks the junctions between its own cells. Clinically, they are manifested by the formation of transient pustules, vesicles and bubbles on the skin of the animal.
There are different forms of pemphigus of varying severity, which are distinguished by the depth of the epidermal involvement and by the fact that they are localized or more extensive.
We distinguish as follows:
- superficial pemphigus which include erythematous and foliaceous pemphigus,
- the so-called "malignant" deep pemphigus which include pemphigus vegetans, pemphigus vulgaris and pemphigus paraneoplastic.
What causes pemphigus in dogs?
The cause of pemphigus remains unknown to this day, although several hypotheses have been put forward among:
- genetic causes (predisposition of certain dog breeds and suspicion of hereditary transmission),
- a triggering of the disease by a viral infection and in particular by the herpes virus,
- the intervention of a hypersensitivity reaction to drugs,
- exposure to ultraviolet (UV) rays,
- the concomitant presence of a malignant tumor.
What are the symptoms of pemphigus in dogs?
There are several types of pemphigus that often vary in their clinical appearance.
The three most common types of pemphigus are pemphigus foliaceus, pemphigus vulgaris, and pemphigus erythematosus.
Pemphigus foliaceus
Pemphigus foliaceus is the most common form of pemphigus in dogs and cats, although it is still quite rare.
Pemphigus foliaceus is most often observed in middle-aged dogs, around 4 years of age. The breeds most at risk are Akita Inu, Chow-Chow, Dachshund, Collie, Doberman, German Shepherd, Newfoundland, Cocker Spaniel, Shar Pei, Pyrenean Mountain Dog, Bearded Collie, English Springer Spaniel, Afghan Hound, Miniature Pinscher, Finnish Spitz, English Pointer and Schipperke.
Pemphigus foliaceus is manifested by the appearance of primary lesions in the form of pustules, vesicles and bubbles which evolve into erosions, crusts and hair loss.The lesions begin to appear most often at the level of the nose, around the eyes and on the pavilions of the ears and then extend to the entire body.
Erythematous pemphigus
This form of pemphigus is similar in appearance to pemphigus foliaceus, although cases are often milder. Predisposed breeds are German Shepherds, Collies and Shetland Sheepdogs.
Vulgar pemphigus
This form of pemphigus attacks the deepest layers of the epidermis, making it the most serious type of pemphigus. Pemphigus vulgaris causes fluid-filled blisters, called vesicles, to form in the junctions between the skin and the mucous membranes and on the skin. The oral cavity is also often affected. These blisters often rupture, leaving painful ulcerative lesions that can be complicated by infection.The prognosis for this form of pemphigus, fortunately very rare in dogs, remains very reserved.
How is pemphigus diagnosed?
The definite diagnosis of pemphigus requires a skin biopsy. Your veterinarian will take a small tissue sample from a skin lesion.
Once the skin sample is taken, it is sent to a pathologist for histological analysis.
How is pemphigus treated?
As pemphigus is an autoimmune disease, treatment requires the use of immunosuppressive molecules. Your animal will therefore be treated with corticosteroids, locally applied for mild cases, or other immunosuppressive drugs, such as azathioprine.
Affected dogs will generally need to undergo long-term treatment, sometimes for life, in order to limit the symptoms of the disease. Additionally, frequent check-ups by a veterinarian will be required to monitor the response to treatment and also to ensure that the dog does not develop any side effects from the medications.
Since the sun can aggravate lesions, it will also be necessary to avoid exposing affected dogs to UV radiation.