Hair Follicle Tumors - Tumors, typically benign, of the hair follicles.
Hemangiosarcoma - Malignant tumor arising from blood vessels, which typically manifests in the spleen, liver, soft tissues, or even skin. Likely fatal.
Hemeralopia - The inability to see in bright light.
Hemivertebra - Failure of parts of the vertebra (bones of the spine) to develop. May be inherited. Breeds with screw tails technically have hemivertebra in the tail bones.
Hemophilia - Factor VII Deficiency - Also known as Alexanders Disease. Deficiency of a protein involved in the clotting process. Typically one of the less severe forms of Hemophilia.
Hemophilia - Factor X Deficiency - Also known as Stuart-Prower Deficiency. Rare form of Hemophilia, can be moderate to severe. Affects males and females equally. May occur with amyloidosis.
Hemophilia - Factor XII Deficiency - Also known as Hageman Factor Deficiency. Extremely rare and may actually cause thrombosis, or clotting in the bloodstream.
Hemophilia - Fibrinogen Deficiency - Also known as Factor I Deficiency. The deficiency of fibrinogen, a part of the blood clotting process. Causes excessive bleeding.
Hemophilia - Prothrombin Deficiency - Also known as Factor II Deficiency, or Hypoprothrombinemia. Deficiency of prothrombin, a necessary clotting factor. Causes excessive bleeding.
Hemophilia A - Classic Hemophilia - Also known as Factor VIII Deficiency. Most severe form of Hemophilia. It is sex linked recessive and carried on the X chromosome, meaning that females are carriers and males are almost exclusively affected.
Hemophilia B - Also known as Factor IX Deficiency. Severe form of Hemophilia, but extremely rare. Sex linked recessive and carried on the X chromosome, so females are carriers and males almost exclusively are affected.
Hemophilia C - Also known as Plasma Thromboplastic Antecedent or Rosenthal Syndrome. Generally mild Hemophilia, typically provoked by surgery.
Hemorrhagic Gastroenteritis (HGE) - Bloody diarrhea, often accompanied by vomiting and/or refusing food. Unknown origin.
Hepatic Lipidosis - Fatty deposits in the liver which can lead to liver failure. Much more common in cats. Nutritional support can be very helpful.
Hepatocerebellar Degeneration (HCD) - Degeneration of cerebellar cortex and degeneration of the liver. Believed to be inherited recessively. Fatal in early puppyhood.
Hereditary Canine Spinal Muscular Atrophy (HCSMA) - Autosomal dominant inherited disease. Similar to ALS (Lou Gehrigs Disease in humans). Swelling of lower motor neurons and loss of myelin. Leads to weakness, poor eye movement, drooping of head and tail, possible evenual paralysis and death.
Hermaphroditism - The phenotypic presense of both male and female genitalia.
Heterochromia Irides - A condition where more than one color is present in the iris, or each may be a different solid color.
Hip Dysplasia - Malformation of the hip joints.
Histiocytoma - Tumor of certain skin cells.
Hydrocephalus (Water on the Brain) - An abnormal buildup of cerebrospinal fliud in the brain, causing increased pressure on the brain. Can be inherited or secondary to disease. If congenital, often produces domed skull. Fatal in puppies if severe.
Hygroma - Fluid filled cavity covered by dense fibrous tissue. They typically occur in young dogs under the skin covering a bony area, like the elbow, due to repeated trauma or pressure. Generally not painful unless it becomes infected.
Hypertrophic Osteodystrophy (HOD) - Acute lameness due to extremely painful lower joint swelling. Causes vary, including vaccine reaction, bacterial or viral infection, and (some believe) an excess of dietary calcium. Many cases can recover fully.
Hypertrophy of nictitans gland - a condition where the gland of the third eyelid is abnormally large.
Hypoglycemia - Abnormally low blood glucose levels. May be inherited or related to other conditions (i.e. improper dosage of medication for diabetes mellitus). Extreme hypoglycemia may be related to seizures.
Hypomyelinogenesis - Lack of myelin, the insulating cover surrounding nerve cells, at birth. Causes tremors and lack of coordination. May be delayed myelinogenesis, in which case the puppy may become normal by one year of age.
Hypopigmentation - Lack of or decrease in skin pigmentation, particularly on the nose, lips, eyelids. May be seasonal or permanent.
Hypoplasia of Dens (odontoid process) - Incomplete formation of the second cervical vertebra which causes subluxation, resulting in pain, and possible paralysis if severe.
Hypothyroidism - Decrease in the level of thyroid hormones, which results in weight gain, lethargy, depression, and in some cases seizures. Can be inherited or due to damaged pituitary gland or cancer. Treatable with hormone replacement medications.
Inguinal Hernia - Descending of one or more intestinal loops through the inguinal canal (due to weak muscle wall) into the scrotum.
Intervertebral Disc Disease - Abnormal development of the spongy discs between each vertebra. Can cause subluxation, pain, and in severe cases, lameness.
Intussusception - Intestinal problem where one portion of the bowel telescopes into the next, leading to obstruction, inflammation, and decreased blood flow. Serious condition.
Iris Atrophy - Typically in elderly dogs, a shrinking and weakening of the iris, the colored part of the eye that constricts in bright light.
Juvenile amaurotic idiocy - a syndrome characterized by early onset blindness and low mental capacity
Juvenile Cellulitis - Also called Puppy Strangles, because swollen neck lymph nodes can cut off airway. Skin tissue condition that causes swelling, enlarged lymph nodes, hair loss, pustules. Typically affects puppies around 1-4 months.
Keratitis Sicca - Or Keratoconjunctivitis Sicca, Dry Eye Syndrome. Lack of adequate tear production.
Knock Knee - Inward slant of either or both knees. May be due to orthopedic malformation or nutritional deficiency.
Lacrimal Duct Atresia - Deformed or absent tear ducts (which drain tears from the eye) are malformed or missing, causing tears to run down the face. Can cause staining.
Legg-Calve-Perthes disease - Also called Avascular Necrosis of Femoral Head. Damage to the head of the femur, which is the ball portion of the hip joint, due to lack of blood supply. Causes lameness, usually occurs before 12 months of age.
Lens Luxation - Condition where the lens of the eye breaks loose from its attachment and becomes free. Can be primary (inherited) or secondary to glaucoma, cataract, or injury.
Linear IgA Dermatosis - Autoimmune skin disease causing blistering and lesions on skin, and often mouth and throat.
Lip Fold Dermatitis - (Intertrigo) An infection, often with an accompanying bad odor, in the deep folds around the mouth.
Lipidosis - Lipid accumulation in neurons (nerve cells) due to a lysosomal storage disease. Can cause seizures, blindness, loss of mental acuity.
Lissencephaly - Brain malformation in which the surface, normally grooved and convoluted, is instead smooth. Causes mental retardation, poor motor skills, seizures.
Lymphedema - Secondary swelling (edema) caused by excess acumulation of fluids. Can be due to blocked lymph nodes or postsurgical effect of removed lymph nodes.
Lymphoma - Also known as Lymphosarcoma. Malignant cancer of the lymph system. Can occur in many parts of the body, but is typically in the lymph nodes.
Lysosomal Storage Diseases - A variety of enzyme deficiencies. Causes the substance normally metabolized by the enzyme to be stored in excess, causing nerve and other damage.