Blisters and Skin Lesions in Dogs
By Elaine Moore
Canine pemphigus is a potentially severe autoimmune disorder of the skin and mucous membranes affecting dogs.
Similar to pemphigus in humans, canine pemphigus causes blistering eruptions primarily affecting the face, ears, and oral cavity. Several subtypes exist. Pemphigus is caused by an abnormal immune response that causes skin cells to separate. Rarely, cats are also affected.
Types of Pemphigus
The subtypes of pemphigus include Pemphigus foliaceus, pemphigus vulgaris, pemphigus erythematosus and pemphigus vegetans. In addition, dogs may be affected by several related immune mediated skin disorders called pemphigus complex.
- Pemphigus foliaceus—most common type of pemphigus seen in dogs
- Pemphigus vulgaris—second most common type; usually causes the most severe symptoms, including ulcerations around the mouth, anus, prepuce, nose and vagina. Secondary complications are likely.
- Pemphigus erythemtosus—usually symptoms are confined to the head and feet and the ANA test is positive in 50 percent of cases.
- Pemphigus vetetans—considered a less severe form of pemphigus vulgaris with warty growths similar to that seen in viral papillomas that occasionally form ulcers.
Pemphigus foliaceus is most common in Akitas, chow chows, dachsunds, bearded collies, Doberman pinschers, schipperkes, Finnish spritzes, and Newfoundland dogs.
Pemphigus eyrthematosus is more likely to affect collies, Shetland sheepdogs and German shepherds. Pemphigus is most likely in middle-aged dogs (4 years).
Pemphigus disorders cause scaling of the skin, scabs, and pustules with crusting. Early on, lesions are often limited to the head, including the skin near the ears and mouth, and the feet, including the planum and nailbed. As the diseases progress, lesions spread to other parts of the body and blisters form. Blisters in pemphigus can rupture easily, leaving a generalized crusting, and may be hard to detect.
The nose in pemphigus is also susceptible to pigment loss, similar to the changes seen in canine lupus. Other symptoms include fever and loss of appetite. When the foot pads are affected, difficulty in walking may be observed.
A physical examination reveals the presence of blistering eruptions in pemphigoid disorders. The presence of mouth lesions is highly suggestive of pemphigus. A biopsy of the lesion is necessary for a definitive diagnosis of the subtype.
It’s important to determine the subtype present to determine the prognosis and optimal course of treatment. It’s also important to differentiate pemphigus from discoid lupus erythematosus. Immunohistochemical or direct immunofluorescent testing may also be used to determine desmoglein distribution. An altered distribution is seen in some cases of pemphigus foliaceus.
Blood tests for desmoglein and anti-plakin antibodies can also be used to help diagnose pemphigus.
Most cases of pemphigus require the lifelong use of oral corticosteroids, such as prednisone and prednisolone, along with immunosuppressant medications such as azathioprine. Topical corticosteroids and tacrolimus are also used. In cats, chloramphenicol is used in place of azathioprine. After the symptoms are brought into control, the starting dosage can usually be lowered. Because these medications can cause serious side effects, the lowest dose needed to keep symptoms in control is used.
There have been reports of improvement noted with dietary changes, including a raw foods diet. Because sunburn can exacerbate symptoms, sun should be avoided and canine sun blocks are recommended.
© 26 Aug 2008 Copyrighted by Elaine Moore