CONDITION

Pemphigus

Pemphigus is a group of autoimmune skin diseases in which the immune system produces antibodies against proteins that normally hold skin cells together. When those connections break down, fluid-filled blisters form within the layers of the skin. The blisters are often fragile and rupture quickly, so what an owner typically observes is not intact blisters but crusts, scales, and raw or weeping patches, most commonly around the face, ears, and paws. Many owners arrive wondering about persistent scabs that do not heal in the usual way, or skin that seems to peel or crust in waves. In dogs, the most common form targets a protein called desmocollin-1; in cats, the precise target is less well characterised, but the pattern of disease can be similar. Pemphigus can affect animals of any age, though certain breeds may be seen more often. This page explores what pemphigus may look like in day-to-day life, the biology underneath the visible changes, how the condition is investigated and confirmed, and the range of approaches used to manage it over time.

Why this matters now

Pemphigus tends to emerge in middle-aged animals, often appearing between four and eight years in dogs and with a median age of around six years in cats, though any age can be affected. In dogs, certain breeds may be represented more frequently, including Akitas, Chow Chows, and Dobermann Pinschers, though the condition can appear in any breed. In cats, most affected animals are domestic shorthaired or longhaired cats, and no consistent breed or sex predisposition has been established.

The disease may begin abruptly, with lesions developing over days to weeks, or may unfold more gradually over months. Some animals experience a waxing and waning pattern, with waves of pustule formation followed by partial resolution. Lesions often start on the face—particularly around the nose, eyes, and ears—and may then spread to other regions of the body, though the extent and speed of spread varies considerably between individuals.

Signals & patterns

Early signals

Crusts on the nose or face

Honey-coloured or pale crusts may appear on the bridge of the nose, around the nostrils, or near the eyes. These crusts often form after fragile blisters break, though the blisters themselves may be too short-lived to observe.

Scaly or crusted ear flaps

The inner surface of the ear flaps can develop crusts and scales, sometimes with underlying redness. This distribution—affecting the concave side of the pinna—is relatively uncommon in other skin conditions.

Pustules or crusts on footpads

In cats particularly, the margins of the footpads or the skin folds around the claws may develop pustules or thick, caseous crusts. In dogs, footpad involvement can occur but tends to be less prominent early on.

Hair loss in affected areas

Where crusts form, the hair may be lost or easily removed. The underlying skin often appears red and may weep slightly when the crust is dislodged.

Later signals

Widespread crusting and redness

Lesions may extend beyond the face and feet to involve the trunk, limbs, and skin folds. The skin can become generally inflamed, with large areas of crusting and scaling that may peel away in sheets.

Lethargy and reduced appetite

When the skin disease becomes more extensive, some animals—cats in particular—develop signs such as reduced energy, reluctance to eat, or low-grade fever. These signs tend to accompany more generalised skin involvement rather than localised disease.

Swelling of the limbs or face

In some cases, particularly where inflammation is marked, fluid may accumulate in the tissues, leading to puffiness around the face or lower legs. This oedema reflects the wider inflammatory burden.

Click to read about the biological mechanisms

How this is usually investigated

Diagnosis typically begins with a detailed history of when and where the skin changes first appeared, any concurrent medications, and the pattern of progression. The veterinary surgeon will examine the distribution and character of lesions, looking for the crusting and erosions characteristic of pemphigus. Because several skin conditions can produce similar appearances, targeted tests are used to confirm the autoimmune nature of the process and identify which form of pemphigus is present.

Cytology

Purpose: A sample of material from an intact pustule or from beneath a crust is examined under the microscope to look for acantholytic cells—rounded keratinocytes that have separated from their neighbours. The presence of these cells, alongside inflammatory cells, supports a diagnosis of pemphigus.
Considerations: Cytology is rapid and can be performed during the consultation, but intact pustules are often difficult to find because they rupture quickly. The test suggests pemphigus but does not definitively distinguish it from other blistering diseases or confirm the specific subtype.

Histopathology

Purpose: A skin biopsy is examined microscopically to assess the depth and pattern of acantholysis, the layers of skin affected, and the distribution of inflammatory cells. This allows the pathologist to classify the form of pemphigus and exclude other blistering or crusting diseases.
Considerations: Biopsy requires local anaesthesia or sedation, and samples must include an intact pustule or early lesion; older crusted areas may show non-specific changes. Interpretation depends on the quality of the sample and the experience of the pathologist.

Immunofluorescence or immunohistochemistry

Purpose: These specialised techniques detect autoantibodies bound to the surface of skin cells, providing direct evidence of immune-mediated attack on intercellular connections. The pattern of antibody deposition helps confirm pemphigus and can distinguish it from other autoimmune skin diseases.
Considerations: The tests require fresh or specially preserved biopsy samples and are not available at all laboratories. They add diagnostic certainty in ambiguous cases but are not always necessary when history, cytology, and histopathology together paint a clear picture.

Complete blood count

Purpose: A blood count is often checked before starting immunosuppressive treatment to establish a baseline and to identify any concurrent anaemia, infection, or other haematological abnormality that might influence drug choice or monitoring.
Considerations: The complete blood count does not diagnose pemphigus itself; it provides context for safe treatment planning. Results are typically normal in uncomplicated pemphigus.

Chemistry panel

Purpose: Biochemistry helps assess liver and kidney function before initiating immunosuppressive drugs, many of which are metabolised or excreted by these organs. It also identifies concurrent conditions that may complicate management.
Considerations: Like the complete blood count, the chemistry panel supports safe treatment rather than diagnosing the skin disease. Results are often unremarkable unless there is concurrent illness or secondary infection.

Options & trade-offs

Management of pemphigus typically involves suppressing the immune response to reduce autoantibody production and control skin inflammation. The combination of drugs, their doses, and the pace of adjustment vary with the severity of disease, the individual animal's response, and practical constraints such as ease of tablet administration or cost. Different households find different regimens manageable over the long term.

Corticosteroids

Prednisolone or other corticosteroids are started at immunosuppressive doses to bring the disease under control, then gradually reduced to the lowest dose that prevents relapse. In many animals, this forms the foundation of long-term management, sometimes as a sole agent or in combination with other drugs. Treatment is often lifelong, though some animals achieve remission and can be weaned off medication after months to years.

Trade-offs: High-dose corticosteroids can cause increased thirst, urination, appetite, and weight gain, and long-term use carries risks of muscle wasting, skin fragility, diabetes, and increased susceptibility to infection. Lower maintenance doses reduce but do not eliminate these effects, and some animals tolerate steroids poorly even at modest doses.

Steroid-sparing immunosuppressants

Drugs such as azathioprine (used mainly in dogs), ciclosporin, chlorambucil, or mycophenolate may be added to allow a lower dose of corticosteroid or, in some cases, to replace steroids entirely. These agents work through different mechanisms to dampen the immune system and can take several weeks to exert their full effect. Azathioprine is not suitable for cats due to the risk of severe bone marrow suppression; chlorambucil or ciclosporin are alternative options in feline pemphigus.

Trade-offs: Steroid-sparing agents bring their own side-effect profiles—azathioprine and chlorambucil can suppress bone marrow, ciclosporin may cause gastrointestinal upset or gingival overgrowth, and mycophenolate can produce vomiting or diarrhoea. Regular blood monitoring is often needed, and the drugs can be costly. The delayed onset of effect means that initial control still relies on corticosteroids.

Topical and adjunctive therapy

Antiseptic shampoos, topical corticosteroids, or emollients can help manage crusting and secondary bacterial colonisation, particularly on the face and ears. These measures do not replace systemic treatment but can improve comfort and reduce the bacterial load on damaged skin.

Trade-offs: Topical treatments require time and cooperation from the animal, and their benefit is limited to accessible surfaces. They do not address the underlying autoimmune process and are insufficient as sole therapy in most cases.

Trigger identification and avoidance

In a minority of cases, pemphigus appears to follow exposure to a particular drug, vaccine, or environmental factor. Identifying and withdrawing the trigger—when one can be found—may lead to remission or reduce the intensity of immunosuppressive treatment needed.

Trade-offs: A clear trigger is identified in only a small proportion of cases, and even when a suspected agent is withdrawn, the disease may not resolve without immunosuppressive therapy. Distinguishing a true trigger from coincidence can be difficult.

Common misconceptions

Misconception:

"Pemphigus is contagious and can spread to other pets or people in the household."

Reality:

Pemphigus is an autoimmune disease, not an infection. The lesions result from the animal's own immune system attacking its skin cells, and the condition cannot be transmitted to other animals or humans. Hygiene measures are sometimes helpful to reduce secondary bacterial contamination of broken skin, but isolation is not necessary.

Misconception:

"Once the skin clears, treatment can be stopped because the disease is cured."

Reality:

Pemphigus is typically a chronic condition that requires long-term management. Lesions may resolve completely with treatment, but this usually reflects successful suppression of the immune response rather than permanent cure. Stopping medication prematurely often leads to relapse, though some animals do achieve lasting remission after extended treatment and can eventually be weaned off drugs under veterinary guidance.

Misconception:

"All autoimmune skin diseases are the same, so treatment for one should work for another."

Reality:

Autoimmune skin diseases differ in the target antigens, the layers of skin affected, and the tissues involved. Pemphigus, pemphigoid, lupus, and other conditions may share some clinical features but require tailored diagnostic approaches and respond differently to treatment. Diagnosis matters because it shapes prognosis and guides drug selection.

Related conditions

Atopic Dermatitis in Dogs

Atopic dermatitis and pemphigus can both cause chronic skin inflammation and discomfort, though they arise from different immune mechanisms—atopic dermatitis reflects hypersensitivity to environmental allergens, while pemphigus involves autoantibodies attacking skin cell connections. The two conditions may occasionally be considered alongside one another when investigating recurring skin disease, particularly when crust or secondary infection complicates the clinical picture.

Otitis Externa in Dogs

Otitis externa often develops secondary to underlying skin disease, and dogs with pemphigus may experience ear canal involvement as part of the broader pattern of crusting and inflammation. In some cases, persistent or unusual ear disease may prompt investigation for systemic skin conditions including autoimmune processes.

Lymphoma in Dogs

Lymphoma and pemphigus both involve dysregulation of the immune system, and in rare instances immune-mediated skin disease can occur alongside or in response to lymphoid malignancy. The distinction matters because skin lesions in a dog with lymphoma may reflect the cancer itself, a paraneoplastic phenomenon, or a separate autoimmune process.

Hypothyroidism in Dogs

Hypothyroidism has been investigated as a potential contributor to immune dysregulation in dogs, and some older literature suggested an association with autoimmune skin disease, though the evidence for a direct link to pemphigus remains uncertain. Thyroid function may be assessed during the work-up of chronic skin conditions, particularly when multiple body systems appear affected.

Cushings Disease in Dogs

Cushing's disease involves chronic elevation of cortisol, which can alter immune function and skin integrity, and some dogs with pemphigus may develop secondary bacterial or yeast infections that resemble the skin changes seen in hypercortisolism. Distinguishing between primary autoimmune disease and secondary infection in the context of metabolic hormone imbalance can be a relevant diagnostic consideration.

Pemphigus sits within the broader landscape of immune-mediated disease, and some animals with autoimmune skin conditions develop other immune-related disorders over time. Understanding how immunosuppressive drugs work, what monitoring involves, and how to recognise early signs of relapse or drug side effects can be useful conversations to have over the course of management. The trajectory of disease and the ease of control vary widely between individuals, and adjustments to treatment are common as the picture evolves.

Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS