Demodicosis is an overgrowth of demodex mites on your pet. Demodex mites are normal skin inhabitants that live in your pet’s hair follicles but are usually so low in number that you cannot tell they are there. When these mites over multiply, they cause hair loss and secondary bacterial infections. Demodicosis can affect both dogs and cats.


Demodicosis can result from a number of underlying conditions, including an immature immune system, such as in puppies; poor nutrition; the estrus/heat cycle in females; immune-suppressive medication, such as steroids; low thyroid hormone production (hypothyroidism); internal disease, such as cancer; or allergies. Sometimes no underlying reason can be found. Testing to help find the cause is very important.

When generalized demodicosis occurs in dogs younger than six months old, it is often because the condition has been inherited, even though the parents might not have exhibited the disease. Therefore, affected pups should not be bred and should be neutered. Demodicosis is not contagious to other animals or to humans.


Demodicosis can affect any area of the body, but the face, forelegs and feet are the most commonly affected areas in dogs and cats. Cats, meanwhile, tend to display the disease primarily on the abdomen.

Localized demodicosis appears as one or several small, round, red, scaly and occasionally itchy areas of hair loss. This type of the disease is characterized by fewer than five well-defined areas of visible hair loss. The more generalized presentation includes hair loss all over the body or feet.

Whenever your pet is showing signs of a health issue, your first step is to contact your primary care veterinarian. If it is indicated that your pet may suffer from demodicosis or another serious condition, a veterinary specialist is available at an ExpertVet certified hospital.