What is Pemphigus Foliaceus?

Pemphigus Foliaceus is an autoimmune skin disease that occurs when the immune system attacks normal, healthy cells and structures of the body, as if they are diseased cells that should be fought off. The immune system specifically targets the “links” between the cells of the skin, which results in blisters, pus-filled spots, and crusting. 

There are two main types of Pemphigus in pets; Pemphigus Foliaceus, as explained above, and Pemphigus Vulgaris, which is a very rare disease that usually results in deep, painful lesions, and can be life-threatening. Pemphigus Foliaceus is also rare, but usually presents with more superficial skin lesions, and is typically less severe overall. 

Which Pets are at Risk of Pemphigus Foliaceus?

Pemphigus Foliaceus is a rare disease that is usually seen in cats, dogs, horses, and goats. However, despite being rare, it is thought that Pemphigus Foliaceus is one of the most common auto-immune diseases in dogs. 

What Causes Pemphigus Foliaceus?

It is generally unknown what causes Pemphigus Foliaceus in pets. However, there are three possible areas to explore to determine a cause;

Endogenous Causes (Internal)

Endogenous causes are internal factors that may encourage Pemphigus Foliaceus to develop. This can include breed and genetic predisposition, immune system defects, tumours or other medical conditions that may trigger Pemphigus Foliaceus.

Exogenous Causes (External)

Exogenous causes are factors outside of your pet’s body that trigger an overactive immune system response and unusual inflammation. This can include viral infections, over-exposure to UV light, or drug reactions. This could be either a short-term allergic reaction, or can create lasting changes to the immune system which, in turn, can cause Pemphigus Foliaceus. 

Idiopathic Causes (Unexplained)

Idiopathic causes are those that are unexplainable, despite extensive testing. It can be frustrating for owners and vets alike, but in many cases of Pemphigus Foliaceus, we simply don’t know what caused it. 

What are the Signs of Pemphigus Foliaceus?

The clinical signs of Pemphigus are similar across the different types, but will differ slightly by the location of where a symptom presents, and the severity of it. For example, lesions, ulcers, and blisters are common across the common types of Pemphigus, but will be far more severe in Pemphigus Vulgaris.

It is important to note that, in most cases, pet’s will appear mostly well, but with a reduced appetite, and increased lethargy.

Typical signs of Pemphigus Foliaceus can include:

• Hair loss
• Scabs and crusting
• Ulcers (around the head, face, and ears and often the nail beds in cats)
• Further lesions spread across the body over time

Typical signs of Pemphigus Vulgaris can include:

• Pus-filled blisters (vesicles), which often rupture
• Painful ulcers (around the edges of the lips and eyes)
• Other painful lesions that spread to other parts of the body over time

How is Pemphigus Foliaceus Diagnosed?

Pemphigus Foliaceus is diagnosed via a close examination of the skin, to detect clinical signs such as pus-filled blisters and other lesions, followed by a biopsy of the affected skin (this will be usually be performed under general anaesthesia if lesions are location around the face or head). 

These biopsies are then sent away to a laboratory, where a pathologist will examine the cells to see if the links have been disrupted. 

You can learn more about how we diagnose skin conditions in pets in our recent blog, including more information about Scopio; a revolutionary digital cytology tool that can provide answers in just one hour. 

How is Pemphigus Foliaceus Treated?

As Pemphigus Foliaceus develops as a result of an immune system defect, treatments for the disease are largely aimed at reducing the immune system’s attack on skin cells.

To do this, vets will initially use high doses of steroid medication to control the disease, then reduce the dosage down to levels that maintain control over the disease, but do not cause long-term side effects. Other immunosuppressive medications, such as azathioprine, chlorambucil, and cyclosporine are sometimes used alternatively, or in addition to steroid medication to suppress the overactive immune system.

However, if it is suspected that drugs were the trigger for Pemphigus Foliaceus, this will be removed as treatment, and an alternative will be sought. 

Veterinary Dermatology at Knutsford Vets

Knutsford Vets offer a range of veterinary dermatology services to help diagnose and treat your pet’s skin conditions. If you begin to spot the signs of Pemphigus Foliaceus in your pet, get in touch with us as soon as possible as symptoms can worsen over time. We’ll then work with you to try to determine the cause of the disease, and recommend a suitable care plan.