What to Know About Foxes and Mange

Medically Reviewed by Vanesa Farmer, DVM on November 18, 2022
4 min read

Mange is a common skin infection caused by a parasitic mite. While mange affects several mammals, foxes, coyotes, and squirrels are the most widely affected animals. Mange is especially common among red foxes. This article looks at the causes, symptoms, diagnosis, and treatment of mange.

Mange is a skin condition caused by a parasitic mite that can dig deep into an animal’s skin. Several mite species cause mange in wild and domesticated mammals, including foxes. The mite species that typically affects foxes is called Sarcoptes scabiei, commonly known as sarcoptic mange. In many cases, the mite itself is not fatal, but it can cause other complications, such as bacterial skin infections. Crusts that form on the eyelids of foxes may hamper their vision. Once infected, most animals regain their health after treatment.

Sarcoptic mange-causing mites are specific to certain animals, though they can sometimes infect other animals too. While Sarcoptes scabiei infects foxes, the infection can also spread to humans who come in close contact with them. This includes wildlife biologists, veterinarians, researchers, and trappers. Human infections are usually self-contained, as the mites don’t reproduce on human hosts.

Research shows that sarcoptic mange is the leading cause of the dwindling fox population in the U.S. and Europe. The first known outbreak of sarcoptic mange was in 1689. The parasitic mite has infected foxes on every continent except Antarctica.

Sarcoptic mange is a highly contagious skin disease that can lead to fatalities if not treated promptly. A recent example is the fox mange disease reported in the endangered San Joaquin kit fox in California that led to the deaths of many foxes in the habitat. This region was once a thriving hub of the kit fox species.

Sarcoptes scabiei typically need hosts to feed and breed, but it can stay alive for long periods without any host. The mites are invisible to the naked eye and difficult to see. Infections may happen when foxes enter environments where the mites already exist.

Some people try to take the fox out of the environment to prevent the spread of the infection, especially in regions where dogs live, as they’re vulnerable to the parasite too. But this isn’t a long-term solution, as the fox that replaces the earlier one could easily contract the infection from the mites that infested the area. It’s better to treat the fox to help them recover, prevent spread, and address the original cluster of infection.

Fox mange happens when a sarcoptic mite infects the host. The parasite digs deep into the fox’s skin, lays its eggs, and leaves fecal matter. This could lead to massive hair loss, which leaves the fox susceptible to more attacks from mites and subsequent infections. Timely treatment is critical in many cases, as failing to do so could lead to other complications like secondary infections, dehydration, and hypothermia.

Fox mange can also harm the animals’ immune system and cause starvation, driven primarily by internal parasites like tapeworm and ringworm that use the nutrients the fox consumes. Sometimes, starvation can cause death. Some of the most common signs of mange include:

  • Hair loss
  • Skin crusting
  • Acute itchiness
  • Crust on eyelids
  • Skin wrinkles
  • Foul smell from the skin crusts due to secondary infections from bacteria and yeast
  • Skin infections in the face, which may cause blindness, impaired hearing, and inability to eat

Veterinarians diagnose the condition by studying fox skin samples under a microscope to identify the mites causing the infection.

If a fox is infected, it needs treatment before organ failure sets in. Keep in mind that, although you may want to help the animals, they may become aggressive and bite you if you approach them. They will likely react instinctively without realizing you’re trying to help them. It’s best to rely on professional help when it comes to treating foxes, whether it’s doctors or fox trappers.

If the vet can’t treat the foxes in their natural environment, they’ll be treated in captivity. Professionals usually bait a fox and trap them using a fox trap without causing it any harm. Professional fox trappers follow all the regulations and guidelines regarding the drugs and methods used to capture wild animals. Ivermectin is an effective fox mange medication, usually mixed into food. In addition to the infection, it also acts on intestinal worms and ear mites. But it needs to be given carefully, as it may harm other animals and suckling fox cubs.

An ivermectin treatment dose generally follows the schedule below:

  • One dose every three days for the first three weeks
  • One dose every five days after the first three weeks
  • Minimum treatment duration of around four to five weeks (roughly 10 doses in all)

But ivermectin acts only on the mites and doesn't kill the eggs. These eggs may hatch and cause reinfection. Sometimes, vets use a combination of anti-inflammatory, antibiotic, and anti-parasitic medications to treat this condition. Specific diets, fluid therapy, and medicated baths also give foxes some much-needed relief.

While foxes can survive mange without human intervention, severe infections can be fatal. Mange may be the single most reported reason for the death of foxes in specific regions in the U.S., like New Jersey.

Since fox mange is contagious, it can quickly spread to other animals and humans. If the infection has spread to many foxes, and individual treatment isn't possible, the chances of successful treatment are slim. 

The intensity of the spread depends on several factors, like the weather conditions and the season. Foxes infected with mange during the winter generally succumb to the infection. Chances of survival increase in the summer, with some reported incidences of improved health in foxes if their immune system remains healthy. In some cases, secondary infections and starvation can cause death.