Pemphigus foliaceus is the most common autoimmune skin disease of cats, and it shows up as crusty, pustular lesions on the face, ears, and paw pads — frequently confused with severe ringworm or dermatophyte infection. Most cats need lifelong immunosuppression, but with modern protocols the median survival is excellent and many cats achieve drug-tapered remission (Bizikova et al., 2015, Vet Dermatology). If your cat has crusts forming on the nose bridge or ear margins that keep coming back, biopsy is the next step.
Last reviewed: June 2026
What Pemphigus Foliaceus Is
Pemphigus foliaceus (PF) is an autoimmune disease in which IgG autoantibodies attack desmocollin proteins in the upper epidermis. The breakdown produces fragile pustules that rupture quickly, leaving honey-colored crusts. The classic feline pattern involves the nasal planum, periocular skin, ear margins, and paw pads — particularly the claw folds. Some cats develop generalized crusting over the body. The disease is not contagious; it is an internal immune problem and has no infectious cause.
Signs Owners Spot at Home
Early signs are subtle: small crusts on the bridge of the nose that owners try to wipe off, mild redness around the eyes, or a few crusty lesions at the edges of the ears. As disease progresses crusts become more numerous, paw pads thicken with brown waxy material around the claw folds (paronychia), and the cat may lose appetite from oral pain or facial discomfort. Itch is variable — many cats are not very itchy. Fever and lethargy occur in moderate-to-severe disease.
How It's Diagnosed
The hallmark diagnostic is skin biopsy showing subcorneal pustules with acantholytic keratinocytes — characteristic free-floating keratinocyte clusters within a pus-filled space. Cytology of an intact pustule (rare to find one) often shows the same acantholytic cells. As described in Greene's Infectious Diseases of the Dog and Cat (dermatology chapter), differential diagnoses include dermatophytosis, demodicosis, eosinophilic plaque, and bacterial folliculitis. A dermatophyte culture or PCR is almost always run in parallel because ringworm can look strikingly similar.
Treatment
Immunosuppression is the foundation. Modified cyclosporine at 5 to 7 mg/kg orally once daily induces remission in roughly 70 to 90 percent of feline PF cases (Irwin et al., 2012, Vet Dermatology). Prednisolone at 2 to 4 mg/kg daily is often used in combination during induction. Chlorambucil is added as a steroid-sparing agent in cats requiring long-term high-dose steroids. Once remission is reached over 4 to 8 weeks, medications are tapered to the lowest effective dose. Topical tacrolimus 0.1 percent is useful for localized facial lesions.
When to See a Vet
Call your vet today if:
- Persistent crusts on the nose, ears, or paw pads that recur after antibiotics
- Brown waxy debris building up around the claw folds of multiple feet
- A previously responsive cat is flaring with new crusts
- Appetite decline alongside facial skin lesions
- Side effects from immunosuppressants (vomiting, lethargy, infections)
Go to the ER immediately if:
- Widespread skin sloughing with raw exposed tissue
- Severe lethargy with fever in a cat on immunosuppression
- Sudden refusal to eat or drink with obvious oral pain
- Difficulty breathing or facial swelling
- Bleeding wounds that won't stop
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Frequently Asked Questions
How is pemphigus foliaceus different from ringworm?
Ringworm (dermatophytosis) is a fungal infection that is contagious to people and other animals and is confirmed by fungal culture or PCR. PF is an internal autoimmune disease and is not contagious. The lesions can look identical on visual exam — both produce circular crusty lesions — which is why biopsy and fungal testing are usually done together. Treating PF as ringworm with antifungals alone will not improve the disease.
How much does diagnosis and treatment cost?
Initial vet exam typically runs $50 to $150 in the US. A 6 mm skin biopsy with dermatopathology costs $250 to $500. Dermatophyte culture or PCR adds $50 to $150. Compounded cyclosporine liquid for a 4 to 5 kg cat is roughly $80 to $200 per month long-term. Prednisolone is inexpensive ($10 to $30 monthly). Chlorambucil is more costly at $80 to $250 per month. Quarterly bloodwork to monitor liver and CBC adds $100 to $250 per visit. Catching it early with biopsy avoids months of failed antifungal therapy.
Will my cat need lifelong medication?
Most cats need long-term immunomodulation, but many can be tapered to the lowest effective dose over months. Some cats achieve sustained drug-free remission, especially when triggered by a specific drug or vaccine reaction. Most cats stay on low-dose cyclosporine or prednisolone for life.
Is pemphigus foliaceus painful?
Mild cases are mostly cosmetic. Moderate-to-severe disease with paw pad involvement is painful — cats walk gingerly, lick the pads excessively, and may avoid jumping. Crusting around the nose can interfere with smell and reduce appetite. Pain typically resolves with successful immunosuppression.
Still Not Sure if Your Cat Needs a Vet?
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