Skin Blisters (Vesiculopustular Dermatoses) in Dogs

Vesiculopustular dermatosis is any change to the skin that involves blistering or pustules. This non-specific symptom could be a sign of many different diseases, including bacterial infection or an autoimmune response.

Dogs can develop vesiculopustular dermatoses in response to a variety of problems. The most common and treatable is the bacterial skin infection called pyoderma, which is defined by the presence of bacteria and pus-filled blisters. Fungal infections such as dermatophytosis (ringworm) can also cause blistering, but this is rare. Allergic reactions may be another reason for vesiculopustular dermatosis in dogs.

However, chronic blistering without infection is most commonly an autoimmune response in which antibodies attack the cells and proteins in the outer layer of the skin. There are many different inherited conditions that cause blistering; diseases run in families and are more common in certain breeds.

Systemic lupus is the most serious, but bullous pemphigoid and several pemphigus complex disorders can also cause severe blistering and ulceration. Depending on the severity, many of these problems can be controlled with immunosuppressant medication. Sadly, a few are not treatable.

The symptoms of skin blisters in dogs may be generalized (covering the entire body) or they may be confined to a specific area.

• Areas of blistering skin
• Pus-filled pockets resembling pimples
• Severe sores and ulceration
• Scabs
• Flaking, scaly skin
• Loss of pigment in the nose
• Erythema (patches of reddened skin)
• Alopecia (hair loss)
• Blistering areas confined to the head and feet
• Blistering in the junction between different areas of skin, such as around the mouth, nose, anus, or vagina

Types

These are the two types of vesiculopustular dermatoses.

• Pustular – filled sores resembling pimples
• Vesicular – blisters filled with clear liquid

The presence of pustules or vesicles can help your vet identify your dog’s disease, but some dogs may have a combination of both types.

These are some of the diseases that cause vesiculopustular dermatoses in dogs, as well as the breeds with a higher rate of incidence.

Pyoderma 

• Bacterial infection

Dermatophytosis (ringworm)

• Ringworm is a fungal infection that is more common in puppies and tends to cause fur loss and dry skin

Demodicosis or demodectic mange 

• Mite infestation which usually causes intense itching and scabby skin

Hereditary immune-mediated diseases

Lupus

• Systemic or cutaneous lupus erythematosus (SLE or CLE) 

• SLE can affect muscles, joints, blood, or kidneys as well as the skin, while CLE only has cutaneous symptoms
• Collies, Shetland Sheepdogs, German Shepherds

Pemphigus foliaceus

• Pemphigus foliaceus is the most common form of the pemphigus complex with generalized pustules all over the body
• Akitas, Chow Chows, Dachshunds, Bearded Collies, Newfoundlands, Doberman Pinschers, Schipperkes, Finnish Spitzes
  

Pemphigus erythematosus

• A milder form of pemphigus foliaceus with symptoms only on the head and feet
• Collies, German Shepherds, Shetland Sheepdogs

Pemphigus vulgaris

• The most severe form of the pemphigus complex with blisters and severe ulceration in the mouth or other places where the skin and mucus membranes join

Bullous pemphigoid

• An autoimmune response that attacks a protein in the skin. Dogs often have blisters in the mouth and nose
• Collies, Doberman Pinschers

Sterile eosinophilic pustulosis

• An allergic rash characterized by pustules with high numbers of eosinophils

Subcorneal pustular dermatosis

• Pustules and crusting on the feet
• Schnauzers

Linear IgA dermatosis 

• A skin disorder with pustules located just below the surface of the skin

• Dachshunds only

Epidermolysis bullosa

• Epidermolysis bullosa is a hereditary disorder that causes blistering on the skin in response to mild trauma

• The disease causes inflammatory damage to the muscles and skin in young dogs

• Most skin symptoms affect the face

• Collies, Shetland Sheepdogs, and sometimes Chow Chows

Dermatomyositis

• Genetic disorder that affects the skin, muscles, and blood vessels
• Collies, Shetland Sheepdogs
  

Cutaneous drug eruption 

• An allergic skin reaction to certain medications

Your vet will examine your dog all over, focusing on their skin. Bloodwork and urinalysis will check for systemic illness. SLE and some other autoimmune responses may be checked for with specific blood tests.

Other testing will focus on eliminating treatable causes like bacterial, fungal, or parasite infection. These organisms can often be found on a swab or skin scrape, but a biopsy will be needed to evaluate the condition more extensively and identify specific autoimmune responses. This is usually performed with a local anesthetic. A muscle biopsy may also be needed for dogs with suspected dermatomyositis. 

In some cases, it can be difficult to distinguish a specific type of autoimmune disorder, even with a biopsy. Your dog’s age and breed will be relevant, as well as the specific type of symptoms including pustules or vesicles and any signs of systemic illness. Recent exposure to a new drug is also relevant, since allergic reactions could cause similar symptoms.

The vet may prescribe antibiotic or antifungal medication to treat infections. If this is the primary cause, treatment will be effective, but antibiotic-resistant bacterial infections may need to be treated with a non-beta lactam antibiotic.

Autoimmune responses will be treated with immunosuppressant medication. Chemotherapy drugs may be used to debilitate the immune system for severe problems like SLE, pemphigus, or bullous pemphigoid. Dogs with these diseases can sometimes be very ill and may need immediate supportive treatment or hospitalization.

Prednisone, or glucocorticoid medication, may be prescribed for less severe autoimmune responses. Pentoxifylline is used to treat dermatomyositis since prolonged prednisone treatment increases muscle atrophy. 

Vitamin E and fatty acid supplements can help support overall skin health. Medicated shampoos may be recommended to eliminate flaking skin and help to keep secondary bacterial infections in check.

There is no effective treatment for epidermolysis bullosa other than managing symptoms and trying to eliminate discomfort as much as possible.

If bacterial or fungal infection is the primary problem, your dog is likely to make a full recovery.

However, an inherited autoimmune disorder usually needs intermittent treatment and careful long-term management. Many symptoms go into remission with treatment but may flare up again at a later date. The veterinarian will taper off your dog’s medication as symptoms become milder since taking high doses of an immune suppressant increases susceptibility to infection. Frequent check-ups may be needed to monitor your dog’s symptoms and adjust dosage as necessary.

Keeping your dog in good health can help to reduce the likelihood of secondary infection. A healthy diet, good hygiene practices, and dietary supplements recommended by your vet can help maintain your dog’s immune system, especially while taking strong steroid or chemotherapy drugs. Avoiding exposure to sunlight can also help to reduce the severity of some autoimmune responses.

With most conditions, breeding is inadvisable as it can pass the problem on to future offspring. Thus, affected dogs should be spayed or neutered once their skin has settled.

The conditions that cause skin blisters in dogs can be expensive to treat. If you suspect your dog is at risk of vesiculopustular dermatoses, start searching for pet insurance today. Wag!’s pet insurance comparison tool lets you compare plans from leading companies like PetPlan and Embrace. Find the “pawfect” plan for your pet in just a few clicks!