Dry mouth

What is dry mouth – also known as xerostomia?

Changes in the mucous membrane of the mouth are unpleasant concomitant symptoms of many clinical problems. They may be caused either by the disease itself or by its treatment. Dry mouth is known to be a side effect of more than 400 medicinal products – it is also caused by radiotherapy, chemotherapy, autoimmune diseases or metabolic diseases. Older people may also be affected by dry mouth. The reason is usually that they don’t drink enough fluids.

The change in the mucous membrane of the mouth has many consequences for the patient and impairs quality of life:

  • The tongue burns and hurts
  • It hurts to eat
  • The sense of taste is impaired
  • Difficulties swallowing
  • Problems speaking
  • Colonisation of the mouth by pathogens (germs)
  • Inflammations, dental caries, loss of teeth as a result of increased bacterial colonisation

The symptoms not only impair quality of life but may also cause further complications:

Acute inflammations and ulcer development in the mucous membrane of the mouth (oral mucositis) and a fungal infection (thrush) are common concomitant symptoms of dry mouth.

The pain caused on eating may result in a poor diet and this usually causes general deterioration in the patient’s state of health.

What are the causes and risks for the development of dry mouth?

Various factors may cause dry mouth. Either the amount of saliva is reduced as a result of inadequate production by the salivary glands or the composition of the saliva is altered.

Human saliva is produced in the salivary glands. All the salivary glands together produce about 1.5 litres of saliva per day in a healthy individual.

Radiotherapy of the head and neck
Radiation therapy in the head and neck area may damage healthy cells. This may cause temporary impairment or permanent damage of the salivary glands.

The administration of chemotherapy as part of the treatment for cancer may damage the mucous membranes, particularly those of the mouth. Diseases of the oral cavity may result.

Autoimmune diseases
Many autoimmune diseases cause dry mouth. After rheumatoid arthritis, Sjögren’s syndrome is the most common rheumatic disease. It decreases the activity of the lacrimal (tear), salivary and mucous glands.

Metabolic diseases
Diseases of the metabolic system (e.g. diabetes) may result in dry mouth as a result of the impaired autonomic nervous system.

Side effects of medicinal products
Some 400 medicinal products list dry mouth as a side effect. These include diuretics, antidepressants, and analgesics (e.g. morphine). This form of dry mouth generally improves as soon as the medicines are discontinued.

Insufficient fluid intake
Old people, in particular, perceive a reduced feeling of thirst and often drink too little. Even for the elderly, it is still particularly important to drink sufficient water - about 3 litres per day.

What role does lifestyle play in dry mouth?

Lifestyle may also have a major influence on a dry mouth. Alcohol, smoking or significant loss of fluids in sport may result in dry mouth.

How is dry mouth diagnosed?

In order to make a diagnosis, the doctor will ask about daily fluid intake and diet. Certain drinking and eating habits may cause dryness of the mouth.

The most useful method of diagnosis is to measure saliva flow rate. This allows the doctor to find out how much saliva the patient produces per minute. He measures the saliva flow rate at rest and then stimulated saliva secretion. In order to stimulate saliva production, the patient must chew on sugar-free chewing gum, for example, for the test. The doctor can also measure secretion from individual glands.

A physical examination is also necessary to make a diagnosis in cases of dry mouth. The doctor checks the characteristics of the oral mucous membrane and salivary glands and looks for any abnormalities in the oral cavity. He also examines the eyes and nasal region and palpates the lymph nodes.

Additional investigations may be necessary depending on the suspected cause of the dry mouth. These include, for example, determining the composition of the saliva and its pH, a swab for germs in the mouth, an x-ray examination or display of the salivary ducts using contrast medium.

How is dry mouth treated?

Various options are available if the saliva produced by the patient is not sufficient to keep the mouth moist for any length of time:

  • Drinking plenty of water and herbal or fruit teas
  • Rinsing the mouth with water, herbal or fruit teas
  • Letting ice cubes, made of pineapple juice for example, melt slowly in the mouth

These methods usually provide only short-term alleviation.

A longer lasting effect is achieved by saliva substitutes, particularly those based on natural active substances:

“Saliva natura” contains extracts of the valuable medicinal herb Yerba santa, which means “holy herb” and has properties similar to those of human saliva:

  • It forms a protective lubricating film on the mucous membrane of the mouth
  • This facilitates functions, such as chewing, swallowing and speaking
  • The herb has water retention properties that extend the duration of action
  • It improves the protection of the oral mucous membrane against germs, so that secondary diseases can be kept to a minimum.