https://www.dermnetnz.org/topics/oral-manifestatio

https://www.dermnetnz.org/topics/oral-manifes...l-disease/

"Oral signs of Crohn disease
The oral mucosa is commonly affected in Crohn disease with up to one third of patients reported to have oral changes, and even higher in children. In some studies, the oral changes preceded the diagnosis of Crohn disease in 60%. There may be a male predominance.

1. Specific oral mucosal changes: orofacial Crohn disease

In children with Crohn disease, orofacial Crohn disease can be an important presentation preceding the bowel diagnosis.

2. Nonspecific changes in the mouth and surrounding facial skin associated with Crohn disease:

Angular cheilitis
Aphthous ulcers/aphthous stomatitis – has been reported to affect up to 20-30% of patients with Crohn disease, although some studies show no increase in this compared to the general population. These cannot be distinguished clinically from the common aphthous ulcers.
Recurrent abscesses
Redness and scaling around the lips
Pyostomatitis vegetans – very rare in Crohn disease
Dry mouth – can result in dental decay, denture discomfort and infection
Bad breath (halitosis)
Recurrent vomiting and regurgitation can cause oral pain and the acid result in dental decay.
Oral signs of ulcerative colitis
Mucosal changes have been reported in some patients with ulcerative colitis."