Why Would a Dog's Tongue Turn White?

Your dog's tongue works hard as her primary sensory organ and major tool for manipulating food and water. It's filled with a complex network of arteries, veins and capillaries. The tongues of most breeds have a deep pink or red color due to this high circulation, and are the first place you'll see signs of impaired circulation or respiratory function. If your dog's tongue turns pale or white, consult a vet immediately. It usually spells major trouble.

Dog with tongue hanging out
The color of your dog's tongue can be an indicator of lung and heart function.
credit: Chris Amaral/Digital Vision/Getty Images

Impaired Circulation or Oxygen

Any condition that interferes with blood flow can cause a pale tongue. These conditions may stand alone or be related to one another. For example, anemia, shock and severe allergic reactions all affect the circulatory and respiratory systems. Both anemia and allergic reaction can cause shock. Any condition that affects heart or lung function can cause a white or bluish tongue and gums.

Acute Conditions

Acute conditions come on suddenly and last a short period of time. Unfortunately, they're often over fast due to fatality. Acute anemia -- inadequate blood iron, with insufficient quantities of blood oxygen -- can result from illness or internal or external bleeding. Edema is fluid retention in a certain area. It can decrease the amount of blood available for circulation. Either can cause a suddenly pale tongue, as can some poisonings. White spots on the tongue may be an initial sign of allergic reaction.

Shock

Any condition that lowers blood pressure can cause shock and lead to inadequate respiration and cardiac distress. Anaphylactic shock results from allergy. Septic shock results from acute, chronic or recurring bacterial infection. Potential shock-inducing infections include endocarditis (inflammation of the heart lining), pneumonia, urinary tract infections and bite or surgical wound infections. Any condition that compromises the lining of the gastrointestinal tract, diabetes, adrenal disease, cancer and cancer treatments also can cause shock.

Chronic Conditions

Chronic conditions develop gradually and last a long time. Those that affect circulation may cause a white or pale tongue, including leukemia, gastric diseases (especially ones with internal bleeding), liver, respiratory and cardiovascular diseases. Immune-mediated hemolytic anemia is a chronic autoimmune disorder that attacks the red blood cells, resulting in a pale tongue and gums. Chronic anemia also may result from malnutrition or illness, especially liver or gastric illnesses.

Infections and Injuries

Some infections and injuries cause white tongue spots. Oral papillomatosis, or cauliflower tongue, is a wart virus that spreads quickly and dramatically, but usually goes away on its own. Burns, sores and ulcers may present as white spots. All three require veterinary treatment. Sores may arise from injury and become ulcerated when infected with mouth flora. Tongue ulcers can be a sign of underlying illness such as kidney disease, hypothyroidism, periodontal disease, and various cancers and immune system disorders.

White Coating

A white coating on the tongue is distinct from the actual tissue of the tongue turning pale or white. Such coatings usually are caused by Candida yeast, and are called thrush or yeast stomatitis. This infection is very rare in dogs and is usually a sign of a severely compromised immune system. It also can arise in dogs who are taking broad-spectrum antibiotics.