Submental lymphadenitis: This is often the most common cause of submental swelling, typically resulting from an infection in the oral cavity, such as a dental abscess or pharyngitis. The submental lymph nodes become enlarged and inflamed in response to the infection.

Dental abscess or infection: Infections originating from the teeth or gums can cause swelling in the submental area due to the proximity of the infection site to the submental lymph nodes.
Sialadenitis: Inflammation of the submandibular gland, which can be caused by bacterial or viral infections, can lead to swelling in the submental area.
Submental cysts or abscesses: These can form due to various reasons, including infection, trauma, or congenital conditions, leading to localized swelling.

Lymphoma: Although less common, lymphoma can present with lymphadenopathy, including in the submental region. It's crucial to consider this diagnosis to ensure timely treatment.
Metastatic cancer: Cancers from the head and neck region can metastasize to the submental lymph nodes, causing swelling. Early detection is vital for effective management.
Tuberculosis: TB can cause lymphadenitis, including in the submental region, and is a critical diagnosis not to miss due to its public health implications and the need for specific treatment.

Ranula: A type of mucous cyst that occurs in the floor of the mouth, which can sometimes cause swelling that appears submental.
Submental lipoma: A benign tumor composed of fat tissue, which can cause a slow-growing swelling in the submental area.
Branchial cleft cysts: Congenital anomalies that can form cysts in the neck, including the submental area, leading to swelling.
Thyroglossal duct cyst: A congenital anomaly that can present as a midline neck mass, occasionally extending into the submental area, causing swelling.