Blastomycosis is a severe systemic infection caused by the fungal organism Blastomyces dermatidis. The organism grows in the soil in specific regions of the country, including the Missouri, Ohio, Tennessee, and Mississippi River valleys.

Dogs and humans are most at risk for infection; however, cats, horses, and other animals are occasionally affected. Because many tissues can be infected by the organism, the signs of the disease will vary.

Canine Demodicosis

Canine demodicosis is a type of mange that occurs when abnormally high numbers of a mite called Demodex canis multiply on the skin. This mite is normally present in small numbers in the skin of healthy dogs, but when a dog's immune system becomes weakened, the mites can overgrow and cause disease and inflammation of the skin.


Dogs and cats affected with Cheyletiella mites can either be intensely itchy or hardly itchy at all. They will frequently get a dry scale along their backs, which can spread to more severe and body-wide scaling. As the infection progresses, the itching becomes more severe. Patchy hair loss can occur due to severe scratching. Some cats may have very few signs other than self-induced hair loss from chewing/pulling out their fur. In humans, Cheyletiella mites cause a red raised rash on the arms, trunk and buttocks that eventually turns into a yellow-crusted area. Human infections usually resolve in 3 weeks if the host animal is treated.

Color Dilution Alopecia

This is a genetic defect affecting the way pigment is distributed in the hairs of affected dogs. Dogs with unusual haircoat coloration such as blue or fawn are affected. Abnormal pigment (melanin) clumping in the hairshafts and subsequent changes in light refraction are responsible for the unusual coloration, and in severely affected animals, excessive pigment clumping causes breakage of the hairshafts and abnormal or stunted hair growth.

Cushing's Disease

Cushing's disease results from excessive production of cortisol, a hormone normally produced by the adrenal glands. This excessive cortisol production can result from abnormalities in the pituitary gland that cause excessive hormone secretion by the adrenal glands, by tumors within the adrenal glands themselves, or by a combination of these factors.

Ear Hematoma

When an animal has a painful or itchy ear, it may swing its head about or scratch its ear to alleviate the discomfort. This behavior can cause trauma to the animal's pinna, or earflap, that can add even more irritation to the ear.

Ear Infections

An ear infection, or otitis, is an inflammation of the outer, middle, or inner ear canal. Most frequently, an animal will develop otitis in the outer ear that may worsen and spread into the middle ear. Once in the middle ear canal, the inflammation can move into the inner ear or, in cases in which the otitis has originated in the middle ear, the infection can instead progress outward to the external ear.

Ear Mites

Highly contagious, ear mites are a common cause of many ear problems in cats and, less commonly, in dogs. Ear mites are found in cats of all ages, but kittens tend to be infected more commonly. These mites can cause intense itching. Severe trauma to the infected area may result when cats scratch the irritated skin. Often, but not always, a dark, granular substance will be present in the ear canal of a cat with ear mites, and signs of irritation and itchiness will be evident.