Halitosis (bad breath – figure 2) may be due to bad teeth, and infection and ulceration of the gums or oral mucosa. Other causes include infection, and degenerative tumors of the nose and paranasal air sinuses, bronchiectasis and intestinal obstruction. Ketoacidosis, uremia and hepatic failure have specific fetors, as do alcohol and certain drugs, such as paraldehyde.

The lips may be dry and fissured, and fissuring of the angles of the mouth may accompany nutritional problems and anemia.

Examination of the mouth requires a good light. This may be provided by daylight, but usually a torch (figure 3a) or lamp is necessary. A torch, tongue depressor and disposable gloves are useful accessories for detailed inspection and palpation of the mouth. A spatula (figure 3b) allows movement of the lips, cheek and tongue to observe these areas; this may be aided by a dental mirror. Palpation is with a gloved finger, your other hand, placed externally, is used for bimanual exploration of the floor of the mouth and the cheeks. The tongue can be pulled forward and held with a swab (figure 4), to examine its sides and adjacent structures.

The tongue (figure 5) is a good indicator of systemic disease, as well as being prone to specific disorders, such as congenital abnormalities, glossitis, and benign and malignant tumors. There is a good deal of variation of ethnic pigmentation and capillary pattern, such as geographic tongue. The pallor of anemia, central cyanosis and the yellow ting of jaundice may be recognized in all races.

Note any furring of the tongue; many tongue coatings have no clinical significance or may reflect a recent meal, or a specific dietary habit. Dietary deficiencies, such as vitamin C and D, may produce an abnormally smooth tongue; coating is increased in heavy smokers and mouth breathers. Oral candidiasis produces a white fungal coating, it occurs in debilitating disease, prolonged antibiotic or steroid therapy, immunological diseases (e.g. sarcoidosis), immunodeficiency (e.g. HIV) and with immunosuppressive drugs.

Mouth breathing may dehydrate the surface of the tongue, however, when this is accompanied by the loss of skin turgor and sunken eyes, it is a valuable indicator of the general state of dehydration, such as postoperatively, in fevers and with reduced fluid intake. There may be tongue atrophy in the Plumber-Vincent syndrome, associated with angular stomatitis and abnormalities of the gastric mucous membrane.