Deafness [ In Ears ]
Deafness in dogs can be either acquired or congenital. Predisposing factors for acquired deafness include chronic infection, use of certain drugs, and most commonly, age-related changes in the cochlea. Congenital deafness can be genetic, seen sometimes in dogs with merle or white coats, or caused by in utero damage from infections or toxins.

Degenerative mitral valve disease [ In Cardioascular and Circulatory ]
Degenerative mitral valve disease is a common cause of congestive heart failure in dogs, especially small, older dogs. The leaflets of the valve become thickened and nodular, leading to mitral valve regurgitation and volume overload of the left side of the heart. Cavalier King Charles Spaniels have an inherited form of this disease.

Demodex [ In Parasites ]
Demodex also known as demodicosis live in small numbers in the sebaceous glands and hair follicles. These mites can cause inflammation and hair loss, they can also lead to secondary bacterial infections such as fever, lethargy, and in larged lymph nodes.

Dermoid sinus [ In Skin ]
Dermoid sinus a genetic, autosomal skin condition in dogs. It can appear as single or multiple lumps on the dorsal midline.

Diabetes [ In Endocrine Diseases ]
Diabetes in dogs is usually type 1 diabetes, or lack of insulin production due to destruction of pancreatic beta cells. In dogs this is caused by autoimmune disease or severe pancreatitis. Type 2 diabetes, characterized by insulin resistance, is less common in dogs, and can be caused by Cushing's syndrome or chronic glucocorticoid or progestin use. Common signs include weight loss, increased drinking and urination, and cataracts. Treatment involves twice daily insulin doses and use of a diet high in fiber and complex carbohydrates.

Diabetes insipidus [ In Endocrine Diseases ]
Diabetes insipidus in dogs and cats can be central, caused by a lack of antidiuretic hormone (ADH), or nephrogenic, caused by a lack of response of the kidneys to ADH. Neither form is common. Central diabetes insipidus (CDI) is usually idiopathic, but can also be caused by head trauma or tumors of the brain. Nephrogenic diabetes insipidus (NDI) can be primary (hereditary) or secondary (caused by a variety of metabolic and renal diseases, including Cushing's syndrome and pyometra). Because the disease is characterized by an inability to concentrate urine, the most common sign is increased drinking and urinating. Treatment of CDI is to use desmopressin, a synthetic analog of ADH. Treatment of NDI is to treat the underlying cause, if any.

Dilated cardiomyopathy [ In Cardioascular and Circulatory ]
Dilated cardiomyopathy is a disease of heart muscle resulting in atrial and ventricular dilation. It is seen in large dog breeds such as Boxers, Great Danes, and Dobermanns. It is usually idiopathic, but can also be caused by taurine deficiency in Cocker Spaniels or doxorubicin use. Dilated cardiomyopathy usually results in congestive heart failure.

Discoid lupus erythematosus [ In Skin ]
Discoid lupus erythematosus is an uncommon autoimmune disease of the skin in dogs. It does not progress to systemic lupus erythematosus in dogs. The most common initial symptom is scaling and loss of pigment on the nose.

Distichia [ In Eyes ]
Distichia (including ectopic cilia) is an eyelash that arises from an abnormal spot on the eyelid. Distichiae usually cause no symptoms because the lashes are soft, but they can irritate the eye and cause tearing, squinting, inflammation, and corneal ulcers.

Ear infections [ In Ears ]
Ear infections are common in dogs, particularly breeds with hanging ears, such as Beagles, and dogs with narrow ear canals, such as Cocker Spaniels. Other predisposing factors include allergies, ear parasites, and hypothyroidism.

Ear mites [ In Parasites ]
Ear mites in dogs are microscopic members of the species Otodectes cynotis. Symptoms include itching, inflammation, and black debris in the ear.

Ectropion [ In Eyes ]
Ectropion (eyelid folding outward) is a common condition in dogs, usually affecting the lower lid. Breeds associated with ectropion include the Cocker Spaniel, the St. Bernard, the Bloodhound, and the Basset Hound.

Ehrlichiosis [ In Bacterial Infections ]
Ehrlichiosis is a disease caused by Ehrlichia canis and spread by the brown dog tick, Rhipicephalus sanguineous. Signs include fever, vasculitis, and low blood counts.

Elbow dysplasia [ In Skeletal and Muscular Disorders ]
Elbow dysplasia is a condition found more commonly in large breeds. It incorporates several different hereditary conditions of the elbow, including osteochondritis of the medial condyle of the humerus, fragmentation of the medial coronoid process of the ulna, and ununited anconeal process of the ulna.

Entropion [ In Eyes ]
Entropion (eyelid folding inward) is a common condition in dogs, especially the Chow Chow, Shar Pei, St. Bernard, and Cocker Spaniel. Upper lid entropion involves the eyelashes rubbing on the eye, but the lower lid usually has no eyelashes, so hair rubs on the eye. Surgical correction is used in more severe cases.