Stomatitis is a clinical sign of many diseases in large animals. Oral trauma or contact with chemical irritants (eg, horses that lick at their legs after having been blistered with caustic agents) may result in transient stomatitis. Traumatic injury from the ingestion of the awns of barley, foxtail, porcupine grass, and spear grass, as well as feeding on plants infested with hairy caterpillars, also will result in stomatitis in horses and cattle.
Clinical signs commonly associated with acute active stomatitis include ptyalism, dysphagia, or resistance to oral examination. Oral examination is facilitated by sedation, after which the mouth can be examined carefully with the aid of a mouth speculum and a light source. Ulcers should be visually and digitally evaluated to determine whether embedded foreign material (eg, grass awns) is present. If the etiology is ingestion of foreign material, changing the quality and quantity of the hay or removing the animal from a pasture with grass awns may effect recovery.
Differential diagnoses include actinobacillosis, foot-and-mouth disease, malignant catarrhal fever, and bovine viral diarrhea. Epidemic diseases such as bluetongue in ruminants, swine vesicular disease, and vesicular stomatitis in horses must be differentiated from other forms of acute noninfectious or contagious stomatitis.