There are several common allergens or irritants found in oral care products that can potentially cause allergic reactions or skin irritation in some individuals. These include:

1. Sodium lauryl sulfate (SLS): SLS is a foaming agent commonly found in toothpaste and can cause skin irritation or allergic reactions in some people.
2. Flavoring agents: Some individuals may be allergic or sensitive to certain flavoring agents used in oral care products, such as mint or cinnamon.
3. Artificial sweeteners: Certain artificial sweeteners, like saccharin or aspartame, can cause allergic reactions in some people.
4. Preservatives: Preservatives like parabens or formaldehyde releasers, which are used to extend the shelf life of oral care products, can cause skin irritation or allergic reactions.
5. Latex: Some individuals may have latex allergies, and latex can be present in the packaging or as a component in dental appliances or products.

It's important to note that allergic reactions are individual-specific, and not everyone will have the same reactions to these ingredients. If you suspect you have an allergy or sensitivity to a specific oral care product, it is best to consult a healthcare professional or allergist for proper evaluation and advice. They can help determine the specific allergen and provide guidance on suitable alternative products or preventive measures.