Tonsillitis, an inflammation of the tonsils, usually occurs in dogs with another disorder of the lungs or airways, such as disorders of the nose, mouth, or upper throat (for example, cleft palate); chronic vomiting or regurgitation (for example, from an enlarged esophagus); or chronic coughing (for example, with bronchitis). When present, it is most frequently seen in small breeds. Chronic tonsillitis may occur in brachycephalic dogs (those bred to have flattened faced and short noses) along with inflammation of the upper throat. Bacteria are a frequent cause of disease. Plant fibers or other foreign bodies that lodge in a tonsil may produce a localized 1-sided inflammation or abscess. Other physical and chemical agents may cause irritation of the mouth and upper throat and one or both tonsils. Tonsillitis may also accompany tumors in the tonsil because of physical trauma or bacterial infection that enters the diseased tonsil.

Tonsillitis is not always accompanied by obvious signs. Gagging, followed by retching or a short, soft cough, may result in expulsion of small amounts of mucus. Poor appetite, listlessness, salivation, and difficulty swallowing are seen in severe tonsillitis. Enlargement of the tonsils may range from slight to large enough to cause difficulty swallowing or to cause high-pitched, noisy breathing.

Prompt administration of appropriate antibiotics is the usual treatment for bacterial tonsillitis. In dogs that do not respond to initial treatment, bacterial culture and drug sensitivity testing may be needed to identify the best course of treatment. Mild pain relievers are sometimes given for severe pharyngeal irritation, and a soft palatable diet is recommended for a few days until the difficulty swallowing resolves. Most cases of tonsillitis do not require removal of the tonsils (tonsillectomy). The veterinarian will probably recommend tonsillectomy when tumors of the tonsil are present or when there is chronic tonsil enlargement that interferes with airflow.

Last full review/revision July 2011 by Ned F. Kuehn, DVM, MS, DACVIM; Neil W. Dyer, DVM, MS, DACVP; Joe Hauptman, DVM, MS, DACVS; Steven L. Marks, BVSc, MS, MRCVS, DACVIM; Stuart M. Taylor, PhD, BVMS, MRCVS, DECVP