Botflies in Dogs: What They Are and How To Treat Them
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Dogs with botflies have parasitic fly larvae growing beneath their skin, usually causing a swollen lump with a small breathing hole. While botflies in dogs are rarely life-threatening, prompt veterinary treatment is important to remove the larvae, reduce pain, and prevent infection or tissue damage.
If your dog enjoys sniffing around rabbit or rodent burrows—especially during summer and early fall—they may be at higher risk for botflies.
Fortunately, most cases are treatable with a straightforward veterinary procedure, and dogs typically recover well with proper wound care.
Key Takeaways
- Botflies in dogs are parasitic fly larvae that grow beneath the skin, often causing swelling with a small breathing hole or visible wound.
- Dogs usually get botflies after exploring rodent or rabbit burrows, especially during summer and early fall.
- Veterinary removal is recommended as soon as possible to prevent pain, infection, tissue damage, or complications.
Summary
Botflies are the larvae of the Cuterebra fly, a common fly found in North America that looks like a bumblebee. These parasites are also known as cuterebras or warbles. A dog with botflies has a grub-like larva growing under her skin.
Sometimes pet parents will notice a small breathing hole over the swelling where the larva is growing. When the larva completes its growth, it will exit the dog in three to six weeks, often leaving an empty wound or abscess.
While botflies aren’t considered a medical emergency, they should be treated in a timely fashion (during regular veterinary office hours). Make an appointment with your vet as soon as possible.
Symptoms
The most common symptoms of botflies in dogs include:
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Swelling under the skin
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Small pore or breathing hole where movement beneath may or may not be seen
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Crater-like wound appearing on the skin
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Breathing issues, seizures, or fever (rare)
Causes
Botflies found in dogs usually lay their eggs near rodent or rabbit burrows. Dogs typically become infected when they are nosing around these burrows and accidentally encounter a larva.
The larvae enter the dog’s body through open wounds or the nose, eyes, or mouth.
Dogs who like to hunt have a greater risk of getting botflies.
Smaller breed dogs under 10 pounds (like Yorkshire Terriers, Rat Terriers, and Jack Russell Terriers) are more susceptible since they are so low to the ground when snuffling around rodent or rabbit burrows.
In the summer through early fall your pup may have a higher chance of finding botflies, as this is botfly hatching season.
Diagnosis
Most botflies in dogs are diagnosed with a thorough exam.
Your veterinarian will look for a firm swelling and/or pore where a warble is present. Rarely, advanced imaging may be recommended if a botfly moves into the central nervous system, leading to neurologic signs.
Treatment
Botflies in dogs are typically surgically removed.
Your vet will likely sedate your dog or put them under general anesthesia to keep them comfortable and still during the procedure.
Often, dogs are treated with antihistamines to reduce their risk of having an anaphylaxis-like reaction to the parasite as it’s being removed.
The area will be cleaned and sterilized, and the pore will be widened to allow removal of the Cuterebra larva. If there is any dead skin that was damaged from the larval growth, it will be removed and the area thoroughly flushed.
After the procedure, affected dogs are often prescribed antibiotics, like Clavamox, and/or pain medications such as carprofen.
Recovery and Management
After removal of the botfly, the wound needs to be kept clean and allowed to heal from the inside out.
Antiseptic flushes may be helpful. Chlorhexidine solution can be diluted (1 part chlorhexidine flush: 10 parts water) and used to clean the tissue daily.
Topical creams, like silver sulfadiazine or manuka honey, can help healing and soothe irritated tissue.
Always talk to your veterinarian before applying topical products.
Healing usually takes 10–14 days but occasionally longer, depending on the severity of the wound.
Keep your dog on a leash and away from rodent or rabbit burrows while they have an open wound to reduce their risk of reinfection.
Prevention
Botflies are best prevented by keeping your dog away from the burrows or dens of rodents and rabbits.
Regular parasite prevention products, like NexGard Plus or Simparica Trio, might help keep parasites away and kill them when they’re small.
Botflies in Dogs FAQs
How can I tell if my dog has botflies?
Botflies on dogs often look like firm swellings with a central pore, most often on the dog’s face or neck.
How do I get rid of botflies on my dog?
Botflies are treated by carefully and surgically removing them intact (whole).
Killing the larva while it’s still in your dog can increase their risk of having an anaphylactic reaction.
How long can a botfly live in a dog?
The larvae usually develop for two to three months before leaving the host (your dog).
What happens if you don’t remove a botfly from a dog?
If you don’t remove a botfly, it can cause pain and tissue damage while it’s in your dog’s body.
Eventually, all botflies will exit the host, but the wound they leave behind can become infected and may require veterinary care. In rare cases, botflies can lead to a deadly disease called systemic inflammatory response syndrome (SIRS).
