What is a common clinical sign of mast cell tumors in dogs?

Severe itching is a common clinical sign of mast cell tumors in dogs due to the release of histamine and other mediators from the tumor cells. Mast cell tumors can cause localized or systemic allergic reactions, leading to pruritus, which is often pronounced. The itching can be a direct result of the tumor's presence or an inflammatory response to the tumor.

While vomiting, increased urination, and weight loss can occur in dogs with various health conditions, they are not the hallmark signs associated specifically with mast cell tumors. Vomiting may be more related to gastrointestinal issues, increased urination could indicate kidney or urinary tract problems, and weight loss can be a sign of many types of illnesses, including malignancies but is less directly linked to mast cell tumors in comparison to itching. Understanding the specific signs associated with mast cell tumors helps in prompt recognition and treatment.