If Your Cat’s Nose or Ear Scabs Won’t Heal — Warning Signs of Squamous Cell Carcinoma and Early Diagnosis

Oncology/CancerDiseasesMeongsiljang Veterinary Advisory Board

Feline squamous cell carcinoma is a malignant tumor that develops in the skin and mucous membranes, and early detection significantly improves treatment success rates. The main causes are exposure to ultraviolet (UV) radiation and genetic predisposition.

What Is Feline Squamous Cell Carcinoma?

A side-view photo of a cat with a nasal lesion.

Feline squamous cell carcinoma is a malignant tumor that originates from the squamous cells of the skin or mucous membranes. It most commonly appears on areas frequently exposed to ultraviolet light, such as the nose, ears, around the eyes, and lips. In its early stages, it may look like a small, firm nodule. As the lesion progresses, it can grow larger, causing the skin to thicken or peel, and may lead to bleeding or ulceration. White-coated cats are at a higher risk. Early detection is key to improving treatment success rates. If you notice any suspicious lesions, please visit your veterinarian immediately for an accurate diagnosis.

What Are the Main Causes?

- Sun exposure: Prolonged exposure to ultraviolet (UV) rays causes cumulative damage to skin cells in unpigmented and lightly haired areas, significantly increasing the risk of squamous cell carcinoma. This is the most critical risk factor. - Coat and skin pigmentation: White or light-colored cats have less melanin and lighter skin pigmentation, which reduces their natural protection against UV rays and increases their risk. - Age: The likelihood of developing this condition rises with age, and it is commonly observed in senior cats, typically around 9 to 11 years old. - No breed or sex predisposition: To date, no specific breeds or sexes have been identified as having a clear predisposition to feline squamous cell carcinoma. Rather than breed, light skin pigmentation and UV exposure are the key factors. - Association with papillomavirus: Papillomavirus antigens have been detected in some cats and may be associated with lesions, but their exact role remains unclear. Early prevention and management are essential.

The face of a white cat exposed to sunlight

Main Symptoms and Signs

The main symptoms of feline squamous cell carcinoma include gradually enlarging lesions, thickening or peeling of the skin, and the development of bleeding or ulcers. Lesions around the nose can cause sneezing, nasal congestion, and nosebleeds, while those near the eyes may result in redness or increased tearing. Frequent scratching or licking by your cat is also a warning sign.

Skin nodule formation: Small, firm lumps develop in areas exposed to ultraviolet light.

Ulcers and bleeding: The lesions repeatedly peel or bleed.

Sneezing and nasal congestion: Respiratory symptoms arise due to lesions around the nose.

Increased tearing: Lesions near the eyes lead to excessive tear production.

Frequent licking: The cat develops a habit of repeatedly licking the affected area due to irritation.

When to Seek Immediate Veterinary Care

If the lesion grows rapidly, bleeds or discharges pus repeatedly, or if your cat loses its appetite or shows a sudden drop in activity, seek veterinary care immediately. These signs may indicate that the cancer has metastasized or that complications have developed. Early diagnosis and treatment significantly improve survival rates.

Accurate Diagnostic Methods

Feline squamous cell carcinoma is accurately diagnosed through a tissue biopsy. By taking a small sample from the affected area and examining it under a microscope, we can determine whether the cells are malignant. - Tissue biopsy: This is the most reliable method for determining malignancy by analyzing the cellular structure of the lesion. - Imaging tests: CT or MRI scans help assess the depth of the lesion and check for lymph node metastasis. - Blood tests: These evaluate overall health, liver function, and blood values to help formulate a treatment plan. An accurate diagnosis is the foundation for improving treatment success rates.

A veterinarian performing a skin biopsy on a cat

Treatment Options and Step-by-Step Approach

Treatment is determined by the location, size, and metastatic status of the lesion. - Surgical treatment: The goal is complete removal of the lesion, which is the most effective approach. - Radiation therapy: This is used when surgery is difficult or when residual lesions remain. - Pharmacological treatment: This is used as an adjunct in cases of metastasis, and immunotherapy is currently under investigation. Regular follow-up care after treatment is essential for improving survival rates, and consistent monitoring for recurrence is necessary.

Home Care and Management Points

After treatment, regular cleaning and protection of the affected area are essential to prevent infection. Closely monitor the surgical site for any signs of infection, such as redness, pus, or swelling. Keep a consistent record of any changes in your cat’s appetite and activity levels. To minimize UV exposure, consider applying sun-blocking film to windows or keeping your cat indoors. Maintaining a low-stress environment is also important.

Infection Prevention: Keep the affected area clean and watch closely for any signs of infection.

Appetite Monitoring: If you notice a persistent decrease in appetite or water intake, consult your veterinarian immediately.

UV Protection: Install sun-blocking film on windows or keep your cat indoors to limit sun exposure.

Stress Reduction: Ensure your cat has a comfortable and calming environment.

Breed-Specific Considerations and Recurrence Prevention

Cats with light or white coats have less skin pigment (melanin), which increases their risk of developing squamous cell carcinoma. However, no clear predisposition has been identified based on specific breeds or sex, so it is more important to focus on minimizing ultraviolet (UV) exposure and considering skin pigmentation than on breed alone. The risk also rises with age, as this condition most commonly occurs in senior cats around 9 to 11 years old, making regular skin examinations essential for older cats. To prevent recurrence, minimize UV exposure and consistently monitor the affected area.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can feline squamous cell carcinoma be treated?

If the lesion is detected early and completely removed, it is treatable. Wide surgical excision often leads to a cure, and combining it with radiation therapy can help extend survival time.

Does UV-blocking film work?

Yes, installing UV-blocking window film or awnings can significantly reduce your cat’s exposure to ultraviolet rays. Sunscreen is often rubbed off during grooming, and some of its ingredients can be toxic to cats, so UV-blocking film or awnings are especially recommended for white cats.

Should I be concerned even if the lesion is small?

Yes, even early-stage lesions can be malignant. It’s safest to consult your veterinarian if a small nodule changes in appearance or persists.

Does it tend to recur frequently?

The likelihood of recurrence depends on the size of the lesion and the extent of surgical removal. Incomplete excision can lead to local recurrence, so regular check-ups are necessary even after complete removal.

Is it okay if my cat licks the affected area?

Repeated licking can worsen the lesion and cause self-inflicted injuries. It’s a good idea to use an Elizabethan collar (e-collar) to prevent licking.

Treatment Comparison: Surgery vs. Radiation vs. Medication

Item	Suitable Cases	Effectiveness	Side Effects
Surgery	When the lesion is small and localized	High	Infection risk, pain
Radiation Therapy	When surgery is difficult	Moderate	Dermatitis, hair loss
Drug Therapy	When metastasis has occurred	Low	Gastrointestinal abnormalities, fatigue

The treatment method varies depending on the location, size, and metastasis of the lesion. Decide after consulting your veterinarian.

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References

[1] Veterinary Surgical Oncology, 2nd Ed. London, C.A., R.R. Dubilzeig, D.M. Vail, et al. (1996)

[2] The Cat, Clinical Medicine and Management, 2nd Edition. De Campos CB, Nunes FC, Lavalle GE, et al. (2014)

[3] Small Animal Cytologic Diagnosis Canine and Feline Disease, 2nd Edition. Konopka J.B., Witte O.N. (1985)