Bullous Pemphigoid in Dogs: Causes, Diagnosis, and Treatment

By Emiel Maddens · Reviewed in consultation with licensed veterinary professionals · Updated July 2026 · 9 min read

What Is Bullous Pemphigoid in Dogs?

Bullous pemphigoid is a rare autoimmune skin disease in which a dog's own antibodies attack collagen XVII (also called BP180), a structural protein in the basement membrane that anchors the outer skin layer (epidermis) to the layer beneath it (dermis). When these anchoring proteins are damaged, the epidermis separates from the dermis and fluid collects in the gap, producing tense blisters called bullae.

Unlike the pemphigus group of diseases, where the split occurs within the epidermis itself, the separation in bullous pemphigoid occurs at the dermal-epidermal junction, deeper in the skin. This distinction matters because it changes both the appearance of lesions and the way a pathologist confirms the diagnosis.

The condition is uncommon in dogs, representing a small fraction of the autoimmune skin cases seen in referral dermatology practices. Reported cases suggest breeds such as the Collie, Shetland Sheepdog, and Doberman Pinscher may be overrepresented, though bullous pemphigoid has been documented across many breeds and in mixed-breed dogs. Because open blisters and ulcers are painful and prone to infection, prompt veterinary evaluation is important.

What Causes Bullous Pemphigoid in Dogs?

Bullous pemphigoid is caused by a type II hypersensitivity reaction in which autoantibodies (usually IgG) target collagen XVII within the hemidesmosomes, the microscopic rivets that hold the epidermis to the dermis. Once these antibodies bind, they activate complement and recruit inflammatory cells that release enzymes, breaking down the anchoring structures and allowing the skin layers to split apart.

The trigger that first causes the immune system to attack self-tissue is often unknown (idiopathic). In some dogs, however, potential triggers have been identified, including certain medications, ultraviolet light exposure, and, rarely, underlying neoplasia (cancer). Drug-associated cases can develop after exposure to some antibiotics or other systemic drugs, which is why a thorough medication history is part of any workup.

Genetics likely play a role in susceptibility, given the breed associations reported in the veterinary literature. The immune dysregulation seen in bullous pemphigoid shares features with other autoimmune skin diseases, and dogs with one immune-mediated condition may be predisposed to others.

How Do Veterinarians Diagnose Bullous Pemphigoid?

Veterinarians diagnose bullous pemphigoid with a skin biopsy submitted for histopathology, ideally taken from an intact, fresh blister rather than a ruptured or crusted lesion. Because bullae are fragile and rupture quickly, a veterinarian may hospitalize the dog or examine it frequently to catch a fresh lesion at the right moment.

Under the microscope, a pathologist looks for a subepidermal split (separation below the entire epidermis) with an inflammatory infiltrate, which distinguishes bullous pemphigoid from pemphigus, where the split is intraepidermal. Additional confirmatory testing includes direct immunofluorescence or immunohistochemistry to detect antibody deposits along the basement membrane, and specialized ELISA assays can identify circulating antibodies against collagen XVII.

Because the clinical appearance overlaps with other ulcerative diseases, the workup usually includes cytology and bacterial culture of lesions to identify secondary infection, plus bloodwork to screen for underlying disease. Owners can review symptom patterns with the Dog Skin Condition Checker before an appointment, but definitive diagnosis always requires biopsy. Ruling out drug triggers and, in older dogs, screening for internal cancer are important parts of a complete evaluation.

Signs and Symptoms to Watch For

The hallmark sign of bullous pemphigoid is tense, fluid-filled blisters that quickly rupture into painful erosions and ulcers. These lesions favor areas where skin meets mucous membranes, including the lips, gums, eyelids, groin, armpits (axillae), and footpads. Affected dogs are often painful, may run a fever, and can become lethargic or stop eating when oral lesions are present.

Because bullous pemphigoid can look like other blistering diseases, the table below compares it with pemphigus vulgaris, its closest clinical mimic:

Treatment Options for Bullous Pemphigoid

The foundation of treatment is immunosuppressive therapy to switch off the autoantibody attack. Most dogs start on oral corticosteroids such as prednisone or prednisolone, typically dosed at 1 to 3 mg/kg per day initially, then tapered to the lowest effective dose once lesions are controlled. Dogs that need long-term control, or that cannot tolerate steroid side effects, are often placed on steroid-sparing drugs such as azathioprine, mycophenolate, or ciclosporin to reduce cumulative steroid exposure.

Managing secondary infection is a critical part of care, because ruptured blisters expose raw skin that is readily colonized by bacteria such as Staphylococcus pseudintermedius. Topical antimicrobial therapy helps keep these lesions clean while the immune system settles. Chlorhexidine Spray contains 2% chlorhexidine gluconate, which disrupts bacterial cell membranes and reduces surface colonization of Staph and Malassezia on open or eroded skin, supporting the primary immunosuppressive treatment rather than replacing it.

Supportive care includes pain management, an Elizabethan collar to prevent self-trauma, and soft food when oral lesions are present. For deeper background, see our guides on Systemic Lupus in Dogs and Safe Skin Treatment Combinations in Senior Dogs, and review the bacterial skin infections resource for infection control tips. Any topical is an adjunct only; the underlying autoimmune process must be treated systemically under veterinary supervision.

Prevention and Long-Term Management

Bullous pemphigoid cannot be prevented, because the underlying immune dysregulation is not something owners can control, but relapses can often be reduced with careful long-term management. Once remission is achieved, the goal is to find the lowest medication dose that keeps the disease quiet while minimizing drug side effects.

Dogs on immunosuppressive therapy need regular monitoring, including bloodwork every few weeks initially and then every 3 to 6 months, to watch for liver stress, bone marrow suppression, and secondary infections. Because immunosuppressed dogs are more vulnerable to infection, keeping the skin clean and addressing new sores quickly is essential.

Owners should avoid any medications previously linked to a flare, limit intense ultraviolet exposure in photosensitive dogs, and report new blisters or ulcers early rather than waiting. With consistent treatment and monitoring, many dogs live comfortably for years, though owners should understand that this is a chronic condition requiring ongoing veterinary partnership.

Frequently Asked Questions

Is bullous pemphigoid in dogs curable?

Bullous pemphigoid is generally not curable, but it is manageable. With immunosuppressive therapy such as prednisone at 1 to 3 mg/kg per day, tapered to the lowest effective dose, many dogs reach remission and live comfortably, though lifelong monitoring for relapse is usually needed.

What is the difference between bullous pemphigoid and pemphigus in dogs?

The key difference is where the skin splits. In bullous pemphigoid, antibodies attack collagen XVII and the split occurs below the epidermis (subepidermal), producing tense blisters. In pemphigus, antibodies attack desmoglein and the split occurs within the epidermis, producing fragile, flaccid blisters that rupture faster.

How is bullous pemphigoid diagnosed in dogs?

Diagnosis requires a skin biopsy from a fresh, intact blister examined by a pathologist, who looks for a subepidermal split. Direct immunofluorescence, immunohistochemistry, or ELISA testing for antibodies against collagen XVII can confirm the diagnosis.

Can medications cause bullous pemphigoid in dogs?

Yes, some cases are drug-associated. Certain antibiotics and other systemic medications have been linked to bullous pemphigoid, which is why a complete medication history is part of the workup. Any drug tied to a flare should be avoided in the future.

Is bullous pemphigoid painful for dogs?

Yes, the ruptured blisters leave raw, painful erosions and ulcers, especially around the mouth and groin. Affected dogs often need pain management, and oral lesions can be painful enough to reduce appetite, so soft food and prompt treatment are important.

Sources

1. Olivry T, Jackson HA. Canine bullous pemphigoid and other subepidermal blistering autoimmune dermatoses. Veterinary Dermatology. 2001;12(6):283-296.
2. Olivry T, et al. A spontaneous canine model of bullous pemphigoid: autoantibodies target collagen XVII (BP180). Veterinary Dermatology. 2000;11(4):225-234.
3. Miller WH, Griffin CE, Campbell KL. Muller and Kirk's Small Animal Dermatology. 7th ed. Elsevier. 2013;432-500.
4. Bizikova P, Olivry T. Immune-mediated subepidermal blistering dermatoses in dogs. Journal of Small Animal Practice. 2015;56(2):89-99.

Related Reading

• Systemic Lupus in Dogs: How It Affects Skin, Joints, and Organs
• Medication Interactions in Senior Dogs: Safe Skin Treatment Combinations
• Age-Related Immune Decline and Recurrent Skin Infections in Senior Dogs

Emiel Maddens

Founder of Vetified. Develops topical antifungal and antimicrobial formulations for companion animals. Vetified products are listed on DailyMed and manufactured through FDA-registered facilities in the United States.

Veterinary review: All Vetified content is developed in consultation with licensed veterinary professionals and references peer-reviewed research published in journals including Veterinary Dermatology, JAVMA, and Journal of Small Animal Practice.