Pharyngitis is an inflammatory condition of the walls of the oro- or nasopharynx. Pharyngitis may develop secondary to viral or bacterial infections of the upper respiratory tract, eg, strangles in horses Strangles in Horses Strangles is an infectious, contagious disease of Equidae characterized by abscessation of the lymphoid tissue of the upper respiratory tract. The causative organism, Streptococcus equi equi... read more and distemper in dogs Canine Distemper Overview Canine distemper is a highly contagious, systemic, viral disease of dogs seen worldwide. Clinically, canine distemper is characterized by: a diphasic fever leukopenia GI and respiratory catarrh, and read more .
In most species, a common pharynx is present at times other than deglutition. The unique caudal pharyngeal-laryngeal anatomy of horses shows complete separation of the pharynx into two components, the nasopharynx and the oropharynx. (Also see Pharyngeal Lymphoid Hyperplasia in Horses Pharyngeal Lymphoid Hyperplasia in Horses Pharyngeal lymphoid hyperplasia is a common condition of the dorsal pharyngeal wall seen in young horses (1–3 yr old). Horses do not have discrete masses of lymphoid tonsillar tissue; rather... read more .)
Animals affected with pharyngitis have a normal desire to eat and drink; however, they may have difficulty swallowing and may appear dysphagic. Animals with secondary peripharyngeal cellulitis and abscessation may be acutely dyspneic secondary to pharyngeal obstruction. For example, foals affected with suppurative pharyngitis secondary to abscessation of the retropharyngeal lymph nodes can become acutely dyspneic and require an emergency tracheotomy.
The diagnosis of pharyngitis can be made with a complete physical examination, radiographic evaluation of the skull, endoscopic evaluation of the pharynx, and microbial cultures of draining abscesses or nasopharyngeal swabs for viral isolation. In small animals, oral pain and resistance to having the mouth opened may indicate retropharyngeal abscessation and the presence of a penetrating foreign body or oral or tonsillar neoplasia. Abnormal pharyngeal tissue should be biopsied and submitted for histopathologic examination to exclude pharyngeal neoplasia. In small animals, oral examination and/or endoscopic examination is the best diagnostic tool for pharyngitis. In large animals, the diagnosis of pharyngitis is easily made by endoscopic examination of the upper respiratory tract.
Bacterial pharyngitis should be treated with systemic antimicrobials based on results of microbial culture and sensitivity testing. Abscesses should be drained and lavaged when appropriate. Viral-induced pharyngitis should be managed with antimicrobials to prevent secondary bacterial infections. Animals affected with either bacterial or viral pharyngitis should be treated with NSAIDs. Pharyngitis secondary to foreign bodies should be resolved with removal of the offending object and effective surgical drainage accompanied by excision of necrotic tissue.
Racehorses affected by pharyngeal lymphoid hyperplasia can be treated with topical and systemic anti-inflammatory agents such as flunixin meglumine, phenylbutazone, or dexamethasone. A commonly used topical anti-inflammatory treatment includes prednisolone, dimethyl sulfoxide, glycerin, and nitrofurazone. Large pharyngeal masses can also be treated with contact diode laser photoablation. Some veterinarians have also anecdotally suggested that hyperimmunization is helpful in managing pharyngeal lymphoid hyperplasia.
Calicivirus infections in cats may cause mild, moderate, or severe ulceration of the oropharyngeal mucosa. Although specific antiviral therapies are not available, affected cats should be treated with systemic antimicrobials to prevent secondary bacterial infection. Animals that cannot maintain their own hydration because of severe mucosal ulceration may require nutritional and electrolyte supplementation either intravenously or by extraoral tube feeding.
See also pet health content regarding pharyngitis in cats Pharyngitis in Cats Pharyngitis is inflammation of the walls of the throat (pharynx). It accompanies most upper airway viral and bacterial respiratory infections. Calicivirus infections in cats may cause lesions... read more , dogs Pharyngitis in Dogs Pharyngitis is inflammation of the walls of the throat (pharynx). It accompanies most upper airway viral and bacterial respiratory infections, such as distemper in dogs. Other causes include... read more , and horses Pharyngeal Lymphoid Hyperplasia (Pharyngitis) in Horses Pharyngeal lymphoid hyperplasia is a condition that occurs in young horses (1 to 3 years old). Unlike humans, horses do not have masses of lymphoid tissue that make up tonsils. Instead, there... read more .