Last Updated on May 4, 2026 by admin
A warble is a lump in a cat’s skin caused by a botfly larva, most often a Cuterebra larva. Some people call it a wolf worm, but it is not an intestinal worm. It is a larva living under the skin, and it needs veterinary care.
If you see a swollen lump with a small hole, discharge, movement, or a wormlike part inside it, do not squeeze it, cut it, or try to pull it out. Call your veterinarian. Removing a larva the wrong way can leave pieces behind, inflame the wound, or make infection more likely.
What warbles are
Cuterebra botflies usually use rabbits or rodents as hosts. Cats are accidental hosts when they nose around burrows, tall grass, brush, or places where small mammals live. The larva can enter through the mouth, nose, or a small skin opening, then later forms a lump with a breathing hole in the skin.
Warbles are most often noticed on the head, neck, shoulders, or trunk, especially in cats that go outdoors or hunt. Indoor-only cats are at lower risk, though any suspicious skin lump still deserves a proper diagnosis.
Signs of a warble in a cat
- A round swelling or lump under the skin
- A small central hole or pore in the lump
- Crusting, fluid, pus, or a bad smell from the opening
- Licking, scratching, tenderness, or hair loss around the area
- Visible movement inside the hole
- Lethargy, poor appetite, fever, or worsening pain if infection develops
Some Cuterebra cases are more urgent than a simple skin lump. Contact a vet right away if your cat has sneezing, nasal discharge, coughing, breathing trouble, eye swelling, head tilt, seizures, weakness, circling, or sudden behavior changes. Larvae can occasionally migrate to the nose, eye, nervous system, or other sensitive tissue.
What to do at home before the vet visit
Keep the cat indoors and prevent licking or scratching if you can do so safely. An e-collar may help if you already have one, but do not bandage the area tightly and do not put ointments, essential oils, peroxide, alcohol, insecticides, or home remedies into the opening.
Take a clear photo for your veterinarian if the cat tolerates it. Then book the visit. If you are unsure whether a skin problem can wait, use your clinic’s triage line. A routine wellness schedule is useful, but a suspected parasite wound is a reason to contact the vet between normal checkups; this guide explains how often cats need vet care in ordinary circumstances.
How veterinarians treat warbles
Your veterinarian will examine the lump and decide whether the breathing pore can be carefully enlarged enough to remove the larva intact. Some cats need local care, pain control, or sedation so the larva can be removed without tearing it and without causing extra trauma.
After removal, the wound is usually cleaned and flushed. Your vet may prescribe pain relief or antibiotics when there is secondary infection, deep inflammation, or a higher-risk wound. If the signs suggest nasal, eye, respiratory, or neurologic involvement, advanced imaging or referral care may be needed.
Why you should not remove a warble yourself
The unsafe version of this advice is to grab tweezers, squeeze the lump, or cut into it. Do not do that. A warble is connected to living tissue, and the small opening you see is not a simple splinter hole. Home removal can rupture the larva, leave material behind, introduce bacteria, or turn a treatable wound into a much worse one.
It is also easy to mistake another abscess, bite wound, cyst, tumor, or foreign body for a warble. A vet can identify what is actually there and choose the right treatment. For the same reason, home parasite fixes are not a substitute for diagnosis; here is why cat worm home remedies are risky, even though warbles are not intestinal worms.
What happens if a warble is not treated
A larva may eventually leave on its own, but waiting is not a good plan for a pet cat. The wound can become painful or infected, the cat may traumatize the area by licking, and an unusual larval migration can be serious. Veterinary care is the safer choice once you suspect a warble.
Prevention
The most reliable prevention is reducing exposure to rabbit and rodent habitats. Keeping cats indoors, using a catio, supervising outdoor time, and discouraging hunting all lower the odds of contact with botfly larvae.
After outdoor time, run your hands gently over your cat’s coat and skin, especially around the head and neck. Look for new lumps, scabs, or draining spots. Do not apply dog insecticides or unapproved pest products to cats; cats are sensitive to several chemicals, and parasite prevention should come from your veterinarian.
Bottom line
Warbles in cats are treatable, but they are not a do-it-yourself problem. If you see a lump with a breathing hole, discharge, or movement, keep your cat from bothering it and call your veterinarian. Safe treatment means removing the larva intact, cleaning the wound, and watching for infection or unusual migration signs.
Veterinary references: Merck Veterinary Manual’s Cuterebra infestation in small animals and VCA Animal Hospitals’ Cuterebra or warbles in cats.