Skin Disease, Autoimmune (Pemphigus) in Dogs

Pemphigus in Dogs

 

Pemphigus is the general designation for a group of autoimmune skin diseases involving ulceration and crusting of the skin, as well as the formation of fluid-filled sacs and cysts (vesicles), and pus filled lesions (pustules). Some types of pemphigus can also affect the skin tissue of the gums. An autoimmune disease is characterized by the presence of autoantibodies that are produced by the system, but which act against the body's healthy cells and tissues -- just as white blood cells act against infection. In effect, the body is attacking itself. The severity of the disease depends on how deeply the autoantibody deposits into the skin layers. The hallmark sign of pemphigus is a condition called acantholysis, where the skin cells separate and break down because of tissue-bound antibody deposits in the space between cells.

 

There are four types of pemphigus that affect dogs: pemphigus foliaceus, pemphigus erythematosus, pemphigus vulgaris, and pemphigus vegetans.

 

In the disease pemphigus foliaceus, the autoantibodies are deposited in the outermost layers of the epidermis, and blisters form on otherwise healthy skin. Pemphigus erythematosus is fairly common, and is a lot like pemphigus foliaceus, but less afflictive. Pemphigus vulgaris, on the other hand, has deeper, and more severe, ulcers because the autoantibody is deposited deep in the skin. Pemphigus vegetans, which affects only dogs, is the rarest form of pemphigus, and seems to be a gentler version of pemphigus vulgaris, with somewhat milder ulcers.

 

Symptoms and Types

 

• Foliaceus
  • Scales, crust, pustules, shallow ulcers, redness, and itching of the skin
  • Footpad overgrowth and cracking
  • Fluid-filled sacs/cysts in the skin (or vesicles)
  • The head, ears, and footpads are the most commonly affected; this often becomes generalized over the body
  • Gums and lips may be affected
  • Swollen lymph nodes, generalized swelling, depression, fever, and lameness (if footpads are involved); however, patients often are in good health otherwise
  • Variable pain and itchy skin
  • Secondary bacterial infection is possible because of cracked or ulcerated skin
• Erythematosus
  • Mainly the same as for pemphigus foliaceus
  • Lesions are usually confined to the head, face, and footpads
  • Loss of color in lips is more common than with other pemphigus forms
• Vulgaris
  • The most serious of the pemphigus types
  • More severe than pemphigus foliaceus and erythematosus
  • Fever
  • Depression
  • Anorexia may occur if the animal has mouth ulcers
  • Ulcers, both shallow and deep, blisters, crusted skin
  • Affects gums, lips, and skin; may become generalized over the body
  • The underarm and groin areas are often involved
  • Itchy skin and pain
  • Secondary bacterial infections are common
• Vegetans
  • Pustule groups join to form larger patches of oozing lesions
  • Mouth is not usually affected
  • Few symptoms of general illness (fever, depression, etc.)

 

Causes

 

• Autoantibodies: the body creates antibodies that react to healthy tissue and cells as though they are pathogenic (diseased)
• Excessive sun exposure
• Certain breeds appear to have a hereditary predisposition

 

 

Diagnosis

 

Your veterinarian will perform a thorough physical exam on your dog, including a blood chemical profile, a complete blood count, a urinalysis and an electrolyte panel. Patients with pemphigus will often have normal bloodwork results. You will need to give a thorough history of your dog's health and onset of symptoms. Possible incidents that might have precipitated this condition should also be reported to your veterinarian (e.g., exposure to sun).

 

A skin exam is crucial. A skin tissue sample will be taken for examination (biopsy); and pustule and crust aspirates (fluid) should be wiped onto a slide to diagnose pemphigus. A positive diagnosis is achieved when acantholytic cells (i.e., separated cells) and neutrophils (white blood cells) are found. A bacterial culture of the skin may be used for identification and treatment of any secondary bacterial infections, and antibiotics will be prescribed in the event that there is a secondary infection present.

 

Treatment

 

Your dog will need to be hospitalized for supportive care if it is severely affected by the condition. Steroid therapy may be prescribed briefly to bring the condition under control. If corticosteroid and azathioprine therapy is prescribed, your dog will be switched to a low-fat diet, since these medications can dispose animals to pancreatitis. Your veterinarian will treat your dog with the drugs that are specifically suited to the form of pemphigus it has.

 

Living and Management

 

Your veterinarian will schedule follow-up appointments to see your dog every one to three weeks. Standard blood-work will be performed at each visit to check for progress. Once your dog's condition has gone into remission, it may be seen once every one to three months. The sun can worsen this condition, so it is important to protect your dog from excessive exposure to the sun.