Teething or Dental Issues: At 2 years old, children are in the process of teething, and this can cause excessive drooling due to the irritation and inflammation of the gums.

Oral Motor Dysfunction: Difficulty with oral motor skills can lead to problems with swallowing and managing saliva, resulting in excessive drooling.
Gastroesophageal Reflux Disease (GERD): GERD can cause discomfort and lead to increased saliva production as the body tries to neutralize stomach acid.
Allergies or Sinus Infections: Postnasal drip from allergies or sinus infections can stimulate saliva production and lead to drooling.
Neurodevelopmental Disorders: Conditions like cerebral palsy or intellectual disabilities can affect oral motor control and lead to excessive drooling.

Pyloric Stenosis: Although more common in infants, pyloric stenosis can present in toddlers and cause projectile vomiting, which might be mistaken for excessive drooling.
Esophageal Atresia or Tracheoesophageal Fistula: These congenital anomalies can lead to drooling due to the inability to swallow properly.
Botulism: A rare but serious condition that can cause muscle weakness, including the muscles used for swallowing, leading to excessive drooling.

Juvenile Idiopathic Arthritis: Rarely, this condition can cause temporomandibular joint pain and lead to difficulty in managing saliva.
Tuberculosis: In rare cases, TB can affect the salivary glands and cause excessive drooling.
Neurodegenerative Disorders: Conditions like Batten disease or other rare neurodegenerative disorders can affect oral motor control and lead to excessive drooling.