List of dog diseases

This list of dog diseases is a selection of diseases and other conditions found in the dog. Some of these diseases are unique to dogs or closely related species, while others are found in other animals, including humans. Not all of the articles listed here contain information specific to dogs. Articles with non-dog information are marked with an asterisk (*).

Infectious diseases

Viral infections

*Rabies (hydrophobia) is a fatal viral disease that can affect any mammal, although the close relationship of dogs with humans makes canine rabies a zoonotic concern. Vaccination of dogs for rabies is commonly required by law. Please see the article dog health for information on this disease in dogs.
*Canine parvovirus is a sometimes fatal gastrointestinal infection that mainly affects puppies. It occurs worldwide.
*Canine coronavirus is a gastrointestinal disease that is usually asymptomatic or with mild clinical signs. The signs are worse in puppies.
*Canine distemper is an often fatal infectious disease that mainly has respiratory and neurological signs.
* Canine influenza is a newly emerging infectious respiratory disease. Up to 80 percent of dogs infected will have symptoms, but the mortality rate is only 5 to 8 percent.
*Infectious canine hepatitis is a sometimes fatal infectious disease of the liver.
*Canine herpesvirus is an infectious disease that is a common cause of death in puppies less than three weeks old.
* Pseudorabies (Morbus Aujeszky) is an infectious disease that primarily affects swine, but can also cause a fatal disease in dogs with signs similar to rabies.
* Canine minute virus is an infectious disease that can cause respiratory and gastrointestinal signs in young puppies.

Bacterial infections

*Brucellosis is a sexually transmitted bacterial disease that can cause uveitis, abortion, and orchitis in dogs.
*Leptospirosis is an infectious disease caused by a spirochaete. Symptoms include liver and kidney failure and vasculitis.
*Lyme disease* is a disease caused by ''Borrelia burgdorferi'', a spirochaete, and spread by ticks of the genus ''Ixodes''. Symptoms in dogs include acute arthritis, anorexia and lethargy. There is no rash as is typically seen in humans.
* Ehrlichiosis is a disease caused by '' Ehrlichia canis'' and spread by the brown dog tick, '' Rhipicephalus sanguineus''. Signs include fever, vasculitis, and low blood counts.
*Rocky Mountain spotted fever* is a rickettsial disease that occurs in dogs and humans. It is caused by '' Rickettsia rickettsii'' and spread by ticks of the genus ''Dermacentor''. Signs are similar to human disease, including anorexia, fever, and thrombocytopenia.
*''Clostridium'' species are a potential cause of diarrhea in dogs. Associated species include '' C. perfringens'' and '' C. difficile''.
*Kennel cough is an infectious respiratory disease which can be caused by one of several viruses or by '' Bordetella bronchiseptica''. It most commonly occurs in dogs in close confinement such as kennels.

Fungal infections

*Blastomycosis* is a fungal disease caused by ''Blastomyces dermatitidis'' that affects both dogs and humans. Dogs are ten times more likely to be infected than humans. The disease in dogs can affect the eyes, brain, lungs, skin, or bones.
*Histoplasmosis* is a fungal disease caused by '' Histoplasma capsulatum'' that affects both dogs and humans. The disease in dogs usually affects the lungs and small intestine.
*Coccidioidomycosis* is a fungal disease caused by ''Coccidioides immitis'' or ''Coccidioides posadasii'' that affects a variety of species, including dogs. In dogs signs of primary pulmonary disease include a cough, fever, weight loss, anorexia, and lethargy. Disseminated disease occurs when the fungus has spread outside of the lungs and may include clinical signs such as lameness, pain, seizures, anterior uveitis, and localized swelling. Diagnosis of Valley Fever may include multiple tests, including serology and radiology. According to a study performed in the Tucson and Phoenix area, 28% of dogs will test positive for exposure to the fungus by two years of age, but only 6% of the dogs will be ill with clinical disease. There is an increased risk of infection associated with amount of time spent outdoors, a larger roaming space accessed by the dog, and increasing age.
*Cryptococcosis* is a fungal disease caused by ''Cryptococcus neoformans'' that affects both dogs and humans. It is a rare disease in dogs, with cats seven to ten times more likely to be infected. The disease in dogs can affect the lungs and skin, but more commonly the eye and central nervous system.
*Ringworm is a fungal skin disease that in dogs is caused by '' Microsporum canis'' (70%), ''Microsporum gypseum'' (20%), and ''Trichophyton mentagrophytes'' (10%). Typical signs in dogs include hair loss and scaly skin.
*Sporotrichosis is a fungal disease caused by '' Sporothrix schenckii'' that affects both dogs and humans. It is a rare disease in dogs, with cat and horse infections predominating in veterinary medicine. The disease in dogs is usually nodular skin lesions of the head and trunk.
*Aspergillosis* is a fungal disease that in dogs is caused primarily by ''Aspergillus fumigatus''. Infection is usually in the nasal cavity. Typical signs in dogs include sneezing, nasal discharge, bleeding from the nose, and ulcerations of the nose.
* Pythiosis is a disease caused by a water mould of the genus ''Pythium'', '' P. insidiosum''. It occurs primarily in dogs and horses, but can also affect humans. In dogs it affects the gastrointestinal system and lymph nodes, and rarely the skin.
*Mucormycosis is a collection of fungal and mold diseases in dogs including pythiosis, zygomycosis, and lagenidiosis that affect the gastrointestinal tract and skin.

Protozoal diseases

* Giardiasis* is an intestinal infection in dogs caused by the protozoa ''Giardia lamblia''. The most common symptom is diarrhea. The zoonotic potential of giardiasis is controversial.
*Coccidiosis can be caused by a variety of coccidian organisms in dogs, most commonly ''Isospora''. There are usually no symptoms, but diarrhea and weight loss may occur.
*Leishmaniasis* is spread by the sandfly, and in the dog as well as human has both cutaneous and visceral forms. The dog is considered to be the reservoir for human disease in the Americas.
*Babesiosis* is spread by members of the family Ixodidae, or hard ticks. The two species of the genus ''Babesia'' that affect dogs are '' B. canis'' and '' B. gibsoni''. Babesiosis can cause hemolytic anemia in dogs.
* Neosporosis* is caused by '' Neospora caninum''
* Protothecosis in dogs is caused by a mutant form of green algae and is usually disseminated. Symptoms include weight loss, uveitis, retinal detachment, and anal seepage.

Parasites

Internal parasites (endoparasites)

* Trichinosis caused by ''Trichinella spiralis'', '' T. britovi''.
* Echinococcosis is an infectious disease infecting dogs and sheep.
*Heartworm disease is caused by '' Dirofilaria immitis'', which uses the mosquito as its vector. Heartworms live in the pulmonary artery and right ventricle of the heart. Heartworm disease in dogs is spread by mosquitoes that harbor the parasite Dirofilaria immitis. Signs include cough, difficulty breathing, and death. 
* Gnathostomiasis is a disease from mammal feces and undercooked seafood.
*Intestinal parasites
**Hookworms* are a common parasite of dogs. The most common is ''Ancylostoma caninum'', followed by '' Uncinaria stenocephala'' and '' A. braziliense''. Signs include diarrhea, vomiting, and weight loss.
**Tapeworms* are also common and in the dog are usually '' Dipylidium caninum'', which is spread by ingesting fleas and lice. Also common is '' Taenia pisiformis'', spread by ingesting rabbits and rodents. Rare tapeworm infections are caused by species of the genera ''Echinococcus'', '' Mesocestoides'', and '' Spirometra''. There are usually no symptoms.
**Toxocariasis is an infection of '' Toxocara canis'' or ''Toxascaris leonina''. Signs are usually mild, but may include diarrhea, pot-bellied appearance, poor growth, and vomiting.
**Whipworms are parasites that live in the cecum and large intestine. The canine whipworm is ''Trichuris vulpis''.

External parasites (ectoparasites)

*Fleas* cause itching and hair loss. The most common flea in dogs is the cat flea, '' Ctenocephalides felis'', followed by the dog flea, '' C. canis''.
*Ticks* are an external parasite of the dog and can spread diseases such as Lyme disease, Rocky Mountain spotted fever, babesiosis, and ehrlichiosis. They can also cause a neurological disorder known as tick paralysis.
*
* Mites
** Ear mites are microscopic members of the species ''Otodectes cynotis''. Symptoms include itching, inflammation, and black debris in the ear.
** Cheyletiellosis is a mild pruritic skin disease caused by ''Cheyletiella yasguri''. Humans can be transiently infected.
** Chiggers*, also known as harvest mites, can cause itching, redness and crusting of the skin.
** Demodicosis, also known as demodectic mange, is caused by '' Demodex canis'' mites which live in small numbers in sebaceous glands and hair follicles. These mites can cause inflammation and hair loss, and may also lead to secondary bacterial infections such as fever, lethargy, and enlarged lymph nodes.
** Sarcoptic mange is caused by '' Sarcoptes scabiei canis''. Signs include intense itching and scaling, and is contagious to humans.

Diseases and disorders by system

Skeletal and muscular disorders

*Osteoarthritis*, also known as degenerative arthritis, is a common condition in dogs characterized by progressive deterioration of articular cartilage in the joints of the limbs. It can cause a great deal of pain and lameness. Treatment options include medications such as NSAIDs, corticosteroids, and joint fluid modifiers such as glycosaminoglycans. Other treatments include surgery, massage, warm compresses, chiropractic, and acupuncture.
*Hip dysplasia is an inherited disease in dogs that is characterized by abnormal development of the acetabulum and head of the femur. It is more common in large breeds.
*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.
*Luxating patella is a medial or lateral displacement of the patella, or kneecap. It is strongly suspected to be inherited, but can also result from trauma. It is more common in smaller breeds of dog

*Osteochondritis dissecans (OCD) is separation of immature articular cartilage from underlying bone. It is caused by osteochondrosis, which is characterized by abnormal endochondral ossification of epiphyseal cartilage. It is most commonly seen in the stifle, elbow, shoulder, and hock.
*Panosteitis is a common disease of unknown cause that causes pain and a shifting leg lameness in medium and large breed dogs. It affects the long bones of the hind and forelimbs.
* Legg–Calvé–Perthes syndrome, also known as Perthes disease or avascular necrosis of the femoral head, is characterized by a deformity of the head of the femur and hip pain. It occurs in small-breed puppies.
*Back pain* in dogs, particularly in long-backed breeds, such as Basset Hounds and Dachshunds, is usually caused by intervertebral disk disease. It is caused by degeneration and protrusion of the disk and compression of the spinal cord. It occurs most commonly in the cervical and thoracolumbar regions. Signs include back pain, hind limb weakness, and paralysis.
* Congenital vertebral anomalies, including butterfly, block, and transitional vertebrae, and hemivertebrae, are a collection of malformations of the spine in animals. Most are not clinically significant, but they can cause compression of the spinal cord by deforming the vertebral canal or causing instability.
* Craniomandibular osteopathy is a hereditary disease in West Highland White Terriers and also occurs in other terrier breeds. It is a developmental disease in puppies causing extensive bony changes in the mandible and skull. Signs include pain upon opening the mouth.
*Hypertrophic osteopathy is a bone disease secondary to disease in the lungs. It is characterized by new bone formation on the outside of the long bones.
*Hypertrophic osteodystrophy is a bone disease in rapidly growing large breed dogs. Signs include swelling of the metaphysis (the part of the bone adjacent to the joint), pain, depression, loss of appetite, and fever. The disease is usually bilateral in the limb bones.
* Spondylosis*, known as spondylosis deformans in dogs, is growth of osteophytes on the ventral and lateral surfaces of the vertebral bodies. It is usually an incidental finding on radiographs and rarely causes symptoms.
* Masticatory muscle myositis (MMM) is an inflammatory disease in dogs affecting the muscles of the jaw. Signs include swelling of the jaw muscles and pain on opening the mouth. In chronic MMM there is atrophy of the jaw muscles, and scarring of the masticatory muscles due to fibrosis may result in inability to open the mouth (trismus).

Cardiovascular and circulatory

*Platelet disorders
**von Willebrand disease* is a common inherited disease in dogs caused by a deficiency of a protein called von Willebrand factor, which is involved in blood clotting. The disease varies from mild to severe, depending on the amount of von Willebrand factor present in the dog. Signs include spontaneous bleeding and excessive bleeding following surgery, injury, or during an estrous cycle.
**Thrombocytopenia* is a common condition in dogs characterized by low platelet counts. Platelets are used in clotting the blood, so dogs with this condition may have spontaneous bleeding or prolonged bleeding following surgery, injury, or during an estrous cycle. Causes include some rickettsial infections such as ehrlichiosis, cancers such as hemangiosarcoma, or immune-mediated disease.
** Thrombocytosis* is a condition characterized by an excess of platelets. Most cases are physiologic (caused by exercise) or reactive (secondary to some cancers, blood loss, or certain drugs). Rarely the condition is caused by a primary bone marrow disorder. In this last case, the platelets may not function normally, causing the blood to not clot properly.
*Hemolytic anemia* is a type of regenerative anemia found in dogs characterized by destruction of the red blood cell. The most important type is immune-mediated hemolytic anemia, which can be a primary disease or secondary to cancer, infection, drugs, or vaccinations. Antibodies are present on the cell surface, leading to lysis and severe anemia. Other causes of hemolytic lesion include hypophosphatemia, exposure to toxins such as lead, infections such as ehrlichiosis or babesiosis, and rarely, neonatal isoerythrolysis. The behavioral condition pica, especially when involving the eating of concrete dust, tile grout, or sand, may be a sign of hemolytic anemia, indicating the need for a complete blood count to investigate a possible diagnosis.
*Heart diseases
**Degenerative (myxomatous) 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 and Dachshunds have an inherited form of this disease.
**Dilated cardiomyopathy (DCM) is a disease of heart muscle resulting in decreased myocardial contractility. The left ventricle compensates for this disease by growing larger (eccentric or volume overload hypertrophy; AKA dilation). The left atrial is also dilated when the disease is severe. It is seen in large/giant dog breeds such as Boxers, Great Danes, and Doberman Pinscher, but can also be caused by taurine deficiency in American Cocker Spaniels or doxorubicin use. A mutation in the gene that encodes for pyruvate dehydrogenase kinase 4 is associated with DCM in Doberman Pinschers in the USA. Dilated cardiomyopathy usually ultimately results in congestive heart failure. Atrial fibrillation is common in giant breed dogs with DCM. Doberman Pinschers more commonly have ventricular arrhythmias (e.g., premature ventricular complexes; ventricular tachycardia) that predispose them to sudden death (i.e., ventricular fibrillation).
**Congestive heart failure* is the result of any severe, overwhelming heart disease that most commonly results in pulmonary edema (fluid in the lungs), pleural effusion (fluid around the lungs), and/or ascites (fluid in the abdomen). It can be caused by the above two diseases, congenital heart defects such as patent ductus arteriosus, pulmonary hypertension, heartworm ('' Dirofilaria immitis'') disease, or pericardial effusion. Signs depend on which side of the heart is affected. Left-sided heart failure results in rapid and/or difficulty breathing and sometimes coughing from a build-up of fluid in the lungs (pulmonary edema). Right-sided heart failure results in a large liver (congestion) and build-up of fluid in the abdomen (ascites), uncommonly fluid around the lungs (pleural effusion), or, rarely, peripheral edema.
**Sick sinus syndrome* is most commonly seen in female Miniature Schnauzers. It is characterized by sinoatrial node dysfunction and may include atrioventricular node disease and bundle branch block. Electrocardiogram findings include sinus bradycardia, sinus arrest, sinoatrial heart block, and atrial tachycardia. The major clinical sign is fainting (syncope).
** Heart defects
*** Subvalvular aortic stenosis (Subaortic stenosis; SAS) is a congenital disease in dogs characterized by left ventricular outflow tract obstruction by a discrete ring or tunnel of fibrous tissue immediately below the aortic valve. It is inherited in Newfoundlands, and also found in Golden Retrievers, Rottweilers, Boxers, Bulldogs, and Samoyeds. Signs include a left basilar systolic heart murmur, weak femoral pulse, fainting and exercise intolerance. Dogs with severe SAS are predisposed to dying suddenly.
*** Pulmonic stenosis* is a congenital heart disease in dogs characterized by right ventricular outflow tract obstruction. Most commonly the narrowing occurs at the pulmonary valve but it can also occur below the valve (subvalvular) or above the valve (supravalvular). The most commonly affected breeds include terriers, Bulldogs, Chihuahuas, Samoyeds, Beagles, Keeshonds, Mastiffs, and Bullmastiffs. Signs may include exercise intolerance, but often there is only a heart murmur.
***Ventricular septal defect* is a hole in the division between the heart ventricles (interventricular septum). It is a congenital heart disease in dogs. There usually are no signs in dogs except for a heart murmur. However, a large defect can result in heart failure or in pulmonary hypertension leading to a right-to-left shunt.
***Atrial septal defect* is a hole in the division between the heart atria (upper chambers of the heart). It is an uncommon abnormality in dogs. Most are not clinically significant, but large defects can cause right heart failure and exercise intolerance. Standard Poodles are the most common breed diagnosed with ASD in the USA.
***Tetralogy of Fallot* is a congenital heart defect in dogs that includes four separate defects: pulmonic stenosis, a ventricular septal defect, right ventricular hypertrophy, and an overriding aorta. Keeshonds and Bulldogs are predisposed. Signs include cyanosis and exercise intolerance. Polycythemia is often present and, if severe, needs to be controlled with phlebotomy or drugs to suppress red blood cell production.
***Patent ductus arteriosus* is one of the most common congenital heart defect in dogs around the world. It is inherited in toy and miniature Poodles, and seen commonly in German Shepherds, Pomeranians, Bichon Frises, and Malteses. Signs include a continuous heart murmur, bounding (strong) femoral pulse, tachypnea (increased breathing rate), dyspnea (labored breathing), and exercise intolerance.
*** Heart valve dysplasia (including mitral and tricuspid valve dysplasia) is a congenital heart abnormality in dogs. Dysplasia of the mitral and tricuspid valves - also known as the atrioventricular (AV) valves - can appear as thickened, shortened, or notched valves. Chordae tendineae are also usually abnormal.
*** Cor triatriatum*, specifically cor triatriatum dexter, occurs in dogs and is characterized by a fibrous division of the right atrium into two chambers, usually with a hole in between them. It results in right heart failure (ascites). It can be treated by balloon valvuloplasty or surgical resection.
*Pericardial effusion* is a collection of fluid in the pericardium. It is usually serosanguinous (bloody fluid). Serosanguinous accumulation can be caused by cancer, usually hemangiosarcoma or a heart base tumor, idiopathic pericarditis. Rare causes include trauma, clotting disorders, and left atrial rupture. Serous accumulation is rare and caused by heart failure, peritoneopericardial diaphragmatic hernias, uremia, pericardial cysts, or hypoalbuminemia. Rarely pericardial effusion can be caused by infection and consist of pus. An echocardiogram should be done prior to draining the fluid, if possible, to identify the cause (e.g., tumor). Drainage of the fluid ( pericardiocentesis) relieves the clinical signs and, in the case of idiopathic pericarditis, can be curative.
* Pulmonary hypertension* is high pressure in the pulmonary artery. In dogs it can be caused by heartworm disease, pulmonary thromboembolism, or chronic hypoxemia (low oxygen). It can result in right-sided heart disease (cor pulmonale). Signs include difficulty breathing, cyanosis, and exercise intolerance.
*Trapped Neutrophil Syndrome* is an autosomal recessive disease which results in mature neutrophils being unable to migrate from the bone marrow into the blood. Affected pups have chronic infections and fail to thrive. Other symptoms can include stunted growth and a ferret like facial appearance. The disease is common in Border collies.

Nervous system

*Syringomyelia* is a condition where a fluid filled sac develops in the spinal cord. The most important cause in dogs is by a Chiari I malformation, which is when an underdeveloped occipital bone interferes with spinal fluid circulation and results in fluid accumulation in the cervical spinal cord. This is a congenital disease most commonly found in small breeds such as the Brussels Griffon and the Cavalier King Charles Spaniel. Other breeds known to be affected include the Bichon Frise, Boston terrier, bull terrier, Chihuahua, French bulldog, Havanese, King Charles spaniel (the English toy spaniel), Maltese, miniature dachshunds, miniature and toy poodles, Papillon, Pomeranian, Pugs, Shih Tzu, Staffordshire bull terrier, and the Yorkshire terrier. Signs may include ataxia, weakness, and neck pain.
* Epilepsy in dogs can be a primary, idiopathic, inherited disorder or secondary to previous head trauma or CNS infections. Idiopathic epilepsy is commonly found in breeds such as German Shepherd Dogs, Beagles, and Dachshunds. The most common sign recurring generalized seizures beginning at a young adult age.
*Cerebellar hypoplasia is an incomplete development of the cerebellum. The most common cause in dogs is an in utero infection with canine herpesvirus. It is also seen associated with lissencephaly in Wire-haired Fox Terriers and Irish Setters, and as a separate condition in Chow Chows.
* Polyneuropathy is a collection of peripheral nerve disorders that often are breed-related in dogs. Polyneuropathy indicates that multiple nerves are involved, unlike mononeuropathy. Polyneuropathy usually involves motor nerve dysfunction, also known as lower motor neuron disease.
*Canine cognitive dysfunction is a progressive disease occurring in older dogs, which is similar to the dementia which occurs in humans with Alzheimer's disease.
* Scotty Cramp is a disease in Scottish Terriers causing spasms and hyperflexion and hyperextension of the legs. It is caused by a disorder in serotonin metabolism that causes a deficiency of available serotonin.
*Cauda equina syndrome*, also known as degenerative lumbosacral stenosis, in dogs is a compression of the cauda equina by a narrowing of the lumbosacral vertebral canal. It is most commonly seen in German Shepherd Dogs. Signs include pain, weakness, and rear limb muscle atrophy.
* Coonhound paralysis is a type of polyradiculoneuritis seen in Coonhounds. The cause has been related to a raccoon bite. Signs include rear leg weakness progressing rapidly to paralysis, and decreased reflexes.
* Tick paralysis* is a disease in dogs caused by a neurotoxin found in the saliva of female ticks. ''Dermacentor'' species predominate as a cause in North America, while ''Ixodes'' mainly causes the disease in Australia. There is a gradual onset of signs, which include incoordination progressing to paralysis, changed voice, and difficulty eating.
* Dancing Dobermann disease is a type of myopathy that primarily affects the gastrocnemius muscle in Dobermann