Pemphigus foliaceus, pemphigus vulgaris, pemphigus erythematosus and pemphigus vegetans—There are several related immune mediated skin disorders called pemphigus complex. These have a common mechanism of action in which the body produces antibodies against the outer layer of the skin (the epidermis).
Pemphigus foliaceus is the most common of these diseases in the dog. It is seen more often in Akitas, chow chows, dachshund, bearded collies, Doberman pinscher, Schipperke, Finnish Spitz and Newfoundland dogs.
Pemphigus erythematosus is second most common and may just be a milder form of pemphigus foliaceus. It is seen more commonly in collies, Shetland Sheepdogs and German shepherds.
Cats are also susceptible to phemphigus disorders. These diseases look exactly alike except that pemphigus erythematosus usually only affects the head and feet.
The more common forms of pemphigus produce scaling skin, scabbiness and sometimes pustules (pus filled sores that look like pimples). Early in pemphigus foliaceus the disease may be confined to the head and feet, making it hard to distinguish from pemphigus erythematosus. Later it spreads to more of the body.
Careful examination of the skin may reveal the presence of blisters, which are very indicative of these diseases. The blisters rupture quickly and may not be seen. If the sores become infected it is possible for severe illness to develop but this is not a common complication.
Pemphigus vulgaris is the most severe form of the disease. In this disorder, there is severe ulceration of the skin, usually where "normal" skin meets "specialized" skin --- around the mouth, anus, prepuce, nose and vagina. The mouth is almost always affected. Secondary complications are more common with pemphigus vulgaris than other forms of pemphigus and can be very severe.
Pemphigus vegetans may be a less severe form of pemphigus vulgaris but it does look different. In this form of pemphigus there are warty growths that may ulcerate. There are a lot of diseases that can look like pemphigus disorders. Drug eruptions (skin reaction to administered medications) are probably the most common "look alike" disorder but systemic lupus erythematosus, discoid lupus and skin cancers are other fairly common diseases that may be confused with pemphigus.
Diagnosis of pemphigus is best done by skin biopsy. Sometimes specialized testing must be done on the biopsy samples -- which often means doing them again.
Treatment of pemphigus vulgaris and pemphigus foliaceus can be pretty frustrating. Usually it is necessary to use prednisone (a corticosteroid) for the life of the dog to control the symptoms of skin scabs and scaling for pemphigus foliaceous and ulceration of skin around mucous membranes (the more "specialized" skin). Prednisone often will not work alone, though. It is usually necessary to use a second immune suppressive medication like azathioprine or chemotherapeutic agents to get complete control of the disease.
Treatment of pemphigus erythematosus and pemphigus vegetans may not be necessary or is usually possible with topical corticosteroids or low to medium dosages of prednisone. Due to the serious immunosuppressive tendencies of the medications used to treat pemphigus diseases it is usually necessary to closely monitor the health of pets under treatment.
To succeed in keeping a dog comfortable when affected by the more severe pemphigus diseases takes close cooperation between the client and veterinarian. Teamwork is important in treating pemphigus.