A bump on your cat’s nose can be anything from a minor scrape or insect bite to a sign of infection, an allergic reaction, or a growth that needs veterinary attention. Most of the time, the cause falls into one of a handful of categories: trauma, infection, an immune-related condition, a fungal disease, or a tumor. What the bump looks like, how fast it appeared, and whether it’s changing all help narrow down the cause.
Bite Wounds and Abscesses
If your cat goes outdoors or lives with other cats, one of the most common explanations for a sudden bump is an abscess from a bite wound. Cat teeth are sharp and narrow, so bite punctures seal over quickly, trapping bacteria under the skin. Over the next few days, infection builds beneath the surface, creating a warm, swollen lump that’s often tender to the touch. Your cat may seem lethargic and lose interest in food as a fever develops.
An abscess will eventually rupture on its own, releasing foul-smelling pus. You might notice the smell before you even see the wound. These bumps typically appear within a day or two of a fight, grow quickly, and feel soft or fluid-filled. They need to be drained and cleaned, and your cat will likely need antibiotics to clear the infection fully.
Eosinophilic Granuloma Complex
Cats have a unique set of immune-related skin reactions grouped under the name eosinophilic granuloma complex. One form, the eosinophilic granuloma, produces raised, circular, yellowish to pink nodules that can appear anywhere on the body but are especially common on the head, face, bridge of the nose, ears, chin, and lips. These bumps are driven by an overactive immune response, often triggered by allergies to fleas, food, or environmental irritants.
Unlike an abscess, these nodules aren’t usually painful or hot to the touch, and they don’t produce foul-smelling discharge. They can persist for weeks or months without changing dramatically. Treatment typically focuses on identifying and removing the allergen along with medications to calm the immune response.
Fungal Infection (Cryptococcosis)
A bump on the nose that keeps growing, especially if your cat also has chronic nasal discharge, sneezing, or noisy breathing, could point to a fungal infection called cryptococcosis. This is the most common deep fungal disease in cats, and the nasal form is by far the most frequent presentation. The fungus enters through the nasal passages and causes progressive swelling of the nose and face, sometimes creating dramatic deformity.
In addition to visible swelling, cryptococcosis produces a thick, sometimes bloody nasal discharge that can come from one or both nostrils. The skin over the swollen area may eventually break down into deep, non-healing ulcers that drain a gelatinous material. You might also notice enlarged lymph nodes under the jaw. Left untreated, the infection can spread to the brain through the thin bone separating the nasal cavity from the skull. Antifungal medication is effective but often requires months of treatment.
Squamous Cell Carcinoma
The bump that worries veterinarians most on a cat’s nose is squamous cell carcinoma, a skin cancer strongly linked to sun exposure. It typically affects cats over 10 years old, with a median diagnosis age of around 11. White cats and cats with light-colored or unpigmented noses are at highest risk because they lack the protective melanin that shields skin from ultraviolet damage.
What makes this cancer tricky is that it starts looking harmless. The earliest sign is often a tiny scab or what appears to be a small scratch on the nose tip (what vets call the nasal planum, the smooth, hairless “button” at the end of the nose). It may flake off and the skin will look normal for a while before the lesion returns. Over time, it becomes more obviously abnormal: a small, poorly defined sore with irregular, hardened borders that may ooze fluid. The surface can be either raised or concave, and it gradually becomes more ulcerated if left alone.
The most common sites for these lesions are the nose tip, ear tips, eyelids, lips, and temples. Because early lesions look so innocent, they’re easy to dismiss. If your cat has a sore on the nose that keeps coming back or won’t fully heal over several weeks, that pattern alone is worth a veterinary visit.
Nasopharyngeal Polyps
In younger cats, a bump or swelling near the nose can sometimes be caused by a nasopharyngeal polyp. These are benign growths that develop from inflamed tissue, usually after a viral upper respiratory infection (the same caliciviruses and herpesviruses that cause kitten “colds”). The virus triggers inflammation in the middle ear or the back of the throat, and over months, a fleshy growth on a thin stalk slowly forms and expands.
Polyps tend to cause breathing problems, noisy breathing, and sometimes ear-related symptoms rather than a visible external bump. But if the growth extends forward into the nasal passages, you may notice swelling along with snoring-type sounds and difficulty breathing through the nose. These polyps are removed surgically and, while they can sometimes recur, the procedure is generally straightforward.
Other Nasal Tumors
Beyond squamous cell carcinoma on the skin surface, tumors can also grow inside the nasal cavity itself. These internal growths cause nasal discharge (often streaked with blood from one nostril), noisy breathing, sneezing, coughing, decreased appetite, and weight loss. As the tumor enlarges, some cats develop visible facial deformity, with one side of the nose or face looking different from the other.
Radiation therapy is the primary treatment for most nasal tumors in cats. Studies show that roughly 92% of treated cats have significant improvement in their symptoms, with median survival times around 11 months. Without treatment, prognosis is poor, likely around three months based on what’s known from similar cancers in dogs.
How Vets Figure Out the Cause
No single visual feature of a nasal bump can reliably tell you what’s causing it. Even imaging like CT scans can suggest a diagnosis but can’t confirm it. The definitive answer for any persistent or growing lump comes from a biopsy, where a small tissue sample is examined under a microscope. This is especially important because some inflammatory conditions can mimic cancer on imaging, and biopsy samples from nasal masses can sometimes miss the true diagnosis on the first attempt.
For suspected infections, your vet may also run blood tests or take a culture of any discharge. For a simple abscess, the diagnosis is usually obvious from the appearance and smell alone.
What to Watch For
A bump that appeared suddenly after your cat got into a scuffle, feels warm, and seems tender is most likely an abscess and will need treatment but isn’t an emergency measured in hours. A small, dry scab on a white cat’s nose that keeps returning deserves attention sooner rather than later, since early-stage squamous cell carcinoma is far more treatable than advanced disease.
The signs that should move your timeline up: any nasal discharge tinged with blood, noisy or labored breathing, facial swelling that’s progressing or asymmetric, a lump that’s been growing steadily over weeks, or a sore that ulcerates and won’t heal. Weight loss and loss of appetite alongside a nasal bump also suggest something more systemic is going on. The earlier any of these conditions is identified, the more options your vet has to treat it effectively.