Fly Strike Dermatitis in Dogs

Flies will bite your dog’s ear and then feed on the blood, causing red, bleeding and very painful sores that are located around the edges of the ear. Dogs that have ears that hang down generally have fly strike dermatitis on the front edge of the ear. Dogs that have erect ears will generally have fly strike dermatitis around the tip of the ear. There have been severe cases where the face is involved. The bite wounds are also susceptible to maggots.

Fly strike dermatitis is also known as myiasis. It is caused when your dog’s ear becomes irritated by biting flies and is mainly a warm weather disease. Fly strike dermatitis usually affects dogs that live primarily outdoors.

If your dog exhibits any of the following symptoms, be sure to make an appointment with your veterinarian. When you first notice signs of fly strike dermatitis, be sure to bring your dog inside where there are no flies to aggravate the wounds. You may notice small, white larva on the broken skin, sometimes the larva may be moving. A foul smell may also be present coming from the open sores. 

• Visible maggots
• Visible larvae 
• Foul smell 
• Lethargic
• Unwilling to eat or drink
• Shaking their head 
• Painful, bloody ears or open wounds

Fly strike dermatitis is caused when flies bite your dog’s ears and then feed on the blood. This causes open wounds that are painful and bloody. The female fly will lay their eggs in the open wound. Maggots are then present and they eat away at the flesh on your dog’s ears. In severe cases, your dog’s face may be compromised as well and open wounds present. 

Fly strike dermatitis will usually occur during warm months and to dogs that primarily live outdoors where fly infestations are more prevalent. Dogs that live in dirty conditions are also more prone to fly strike dermatitis.

When you first arrive for your veterinary appointment, you will need to provide your dog’s medical history especially if this is a veterinarian who has not seen your dog before. Be sure to describe any symptoms that you have seen and give any background information on your dog that may help your veterinarian properly diagnose your dog’s condition. 

Your veterinarian will conduct a physical examination and will order routine diagnostic tests such as a biochemistry panel, complete blood count and urinalysis. A thorough examination of the affected areas will also be done. Your veterinarian may opt to perform a skin scraping of the open wounds and order a fungal culture, bacterial culture and skin biopsy. 

Once your veterinarian has diagnosed fly strike dermatitis in your dog, they will then discuss what treatments will be required to eradicate the maggots and heal the wounds.

Treating fly strike dermatitis can be a long process depending on your dog’s overall health. Initial treatments may require your dog to be anesthetized since it can be painful to eradicate maggots, larvae and remove dead or dying skin tissue. 

The affected area will be clipped or shaved so your veterinarian can clearly see the wounds and any larvae that are present. The open wounds will be flushed and cleaned with an antibiotic solution. Any skin tissue that is dead or dying will need to be removed. This is done by debriding the wound. Oral and topical antibiotics will be given to promote healing and prevent further infection. In some cases, a corticosteroid will be prescribed to prevent more inflammation from occurring. 

You will need to follow your veterinarian’s treatment plan and give any medications as prescribed. When your dog goes home, you will need to keep them indoors to avoid a re-infestation.

You will need to keep your dog’s open wounds clean and dry. Be sure to follow up with your veterinarian to ensure that your dog is recovering properly. If you have any questions about your dog’s care or the medications prescribed, direct those to your veterinarian. 

You can take steps to prevent fly strike dermatitis from happening to your dog. Do not leave them outdoors during warm or hot weather since this is when flies are the most active. Use pet safe fly sprays to deter flies from biting, pay special attention to your dog’s ears when using sprays. You can also use environmental sprays or granules around your dog’s primary living quarters to keep flies at bay.