Dry mouth is also referred to as xerostomia. It is an unpleasant condition that can be related to many diseases. Xerostomia usually occurs because of insufficient production of saliva. Saliva is normally produced by three pairs of large salivary glands (parotid, submandibular, sublingual) and many other small glands located in oral cavity. Lack of saliva is associated not only with dry mouth, but also with bad breath, rapid formation of plaque and tooth decay.
Insufficient intake or increased fluid output leads to dehydration and this is associated with lower production of saliva. Increased fluid losses are present for example during physical exertion, while staying in a hot environment, in fever conditions, in untreated diabetes and in disease known as diabetes insipidus.
Stress, anxiety and fear lead to stimulation of organism defense systems (sympathetic nervous system) that in many ways affects human body including reduction of saliva production. Dry mouth is a common complaint of psychiatric patients with anxiety disorders.
This autoimmune disease is related to damage inflicted on salivary glands by our own immune system. Impaired function of the glands leads to reduced saliva and tears production causing dry mouth and increasing the threat of eye infections.
It is important to know affected person’s habits including fluid intake, smoking, current medication etc. Diabetes may be ruled out by blood test (glucose blood level). Sjögren's syndrome and rare diseases like diabetes insipidus fall within the competence of internal physicians.
Treatment depends on the cause. Adequate fluid intake, smoking cessation and current medication changes usually helps to increase saliva production.