In human biology, sialorrhea is a medical condition characterized by drooling, or excessive salivation. The drooling may be caused by the production of too much saliva or by a decreased ability to swallow, or by a combination of these two factors. There are a number of other terms by which sialorrhea is also known, including ptyalism, hyperactive salivary flow, polysialia, and sialism.
Saliva is produced in the mouth from three major salivary glands, the parotid gland, the submandibular gland, and the sublingual gland, as well as from a number of smaller glands. The amount of saliva that is produced is affected by several different factors, and when much more saliva is produced than is required, drooling may result. It is particularly noticeable when the excess saliva production is accompanied by impaired swallowing.
Sialorrhea causes can be varied. It can be a symptom of one of a number of neurological disorders, such as cerebral palsy and Parkinson’s disease. Sialorrhea diagnosis can also be linked with infection or poisoning. Heavy metal poisoning in particular, such as mercury poisoning, tends to induce drooling. Poisoning with insecticides and nerve gases is also known to have a similar effect.
A number of medicinal drugs are known to have induced sialorrhea as a side effect. The most commonly reported of these are antipsychotic drugs, in particular a drug called clozapine. Some of the drugs that are used to treat Alzheimer’s disease and related disorders are also often associated with drooling.
Treatment for sialorrhea usually depends on the root cause. If it is a side effect induced by prescribed drugs, then treatment is often limited to managing the excess salivation to a point where it can be controlled without too much impact on the patient. While drooling is often considered a cosmetic problem for patients, it can lead to hygiene problems, dehydration, and skin problems around the mouth. In some cases, drooling can also significantly hinder the ability of the patient to successfully engage with speech therapy where required, for example in some neurological disorders.
There are certain drugs that may be used in sialorrhea treatment. These drugs largely work by affecting the nervous system to reduce salivation, but they often have significant side effects. In extreme cases, where drooling is a long-term problem, surgical treatment of sialorrhea has been used, in the form of removal of one or more of the major salivary glands.