Approximately 17 years ago, when I was an assistant professor at the University of Pennsylvania, Kristin Walker, DVM, DAVDC, and I saw a one-year-old male neutered golden retriever that presented with unusual oral lesions. The pattern of lesions was very interesting and left a lasting impression on me. There were multiple focal punctate raised lesions throughout the mouth, with most of the lesions concentrated in the area of the mucogingival junction. (Figures 1A, 1B). There were also multiple lesions on the dorsal surface of the tongue (Figures 2A, 2B). Figure 1A. Multiple raised nodules along the mucogingival line dorsal to the right maxillary canine tooth and along the mucocutaneous junction of the rostral upper lip. Photo courtesy Dr. John R. Lewis Figure 1B. Multiple raised bumps of the oral mucosa at the mucogingival line dorsal to the incisors and near the mucocutaneous junction of the upper lip. Photo courtesy Dr. John R. Lewis It would not be wrong to assume these raised bumps were vesicles associated with autoimmune disease, such as bullous pemphigoid, pemphigus vulgaris, systemic lupus erythematosus, or discoid lupus erythematosus. However, this dog had a history of going on a long hike with his owners the weekend prior, and when we biopsied the affected areas, the pathologist saw “ulcerative pyogranulomatous stomatitis with intralesional plant material.” After discussion of this diagnosis with the owners, they mentioned the dog had picked up numerous cockleburs (Xanthium strumarium) that adhered to the dog’s hair coat, which it tried to lick off its fur before the owners had an opportunity to remove them. If you look at the cocklebur seed under magnification, each projection has a long, curved hook on the end. When a dog tries to lick them from its matted fur or tries to eat them, the hooks can lodge into the mucosa of the mouth, and the submerged portion of the projection breaks off beneath the mucosa. Why are the lesions so characteristically manifested at the mucogingival line? My theory is when the seeds are chewed upon, they contact the teeth and gingiva, but since the gingiva is a specialized, durable masticatory mucosa that is keratinized, the sharp hooks do not damage it. The first spot they can lodge is the soft mucosa at the mucogingival line. The penetrated mucosa tries to heal over the site of entry, and a pyogranulomatous foreign body reaction ensues. Figure 2A. Multiple raised red nodules on the dorsal surface of the tongue. Photo courtesy Dr. John R. Lewis. How do we treat what I sometimes refer to as “cockleburitis”? Most of the cases I have seen have been incidental findings with no clinical signs and required no treatment other than client education. However, the patient shown in Figures 1 and 2 had clinical signs of drooling and lip smacking. This patient was placed on nonsteroidal anti-inflammatories after the biopsies, and with tincture of time, the tongue and mucosa looked much more normal at recheck. Figure 2B. Magnified view of the lesions on the dorsal surface of the tongue. Photo courtesy Dr. John R. Lewis What other kinds of plants can cause problems in the oral cavity? In my June 2024 column, I discussed the problem of chewing on sticks.1 Sticks become lodged between the maxillary teeth and can damage the soft tissue and the periodontium. They can also get lodged in the pharynx and penetrate the esophagus. Foxtails have long been known for causing trouble in the oral cavity and elsewhere. In a 2022 study in the Journal of Veterinary Emergency and Critical Care, the most common locations in dogs were the aural canal, cutaneous/subcutaneous space, and nasal canal. In cats, ocular foxtails were most common. Most cases were managed on an outpatient basis, but some cases developed life-threatening diseases that required advanced imaging, endoscopy, and/or surgery.2 We have probably all heard or worked on patients that had to have a lung lobe removed due to a migrating foreign body in the form of a plant awn or a stick foreign body. Next time your pets go for a hike, be aware of any cockleburs or other vegetation that may have gotten caught on their fur and try to remove them before they become a source of oral inflammation or a migrating foreign body. I have only seen a handful of cases of “cockleburitis” throughout my 28-year career, which makes me wonder how common it is. If you have seen this pattern of raised bumps along the mucogingival line, send me an email at info@siloacademy.com. John R. Lewis, VMD, DAVDC, FF-OMFS, practices and teaches at Veterinary Dentistry Specialists and Silo Academy Education Center in Chadds Ford, Pa. References Lewis, JR. Breaking the habit of chewing sticks. Veterinary Practice News, June 2024. https://www.veterinarypracticenews.com/chewing-sticks-habit/ Philp HS, Epstein SE, Hopper K. Clinical and clinicopathological characteristics, treatment, and outcome for dogs and cats with confirmed foxtail foreign body lesions: 791 cases (2009-2018). J Vet Emerg Crit Care. 2022;32(5):653-662.
