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Common disorders affecting the mouth are cold sores on the lip; canker sores and candidal infections of soft tissues of the tongue, cheeks, and gums; and plaque and calculus affecting the gums and teeth. Xerostomia, or lack of saliva, originates from nonoral causes. Halitosis can arise from oral or nonoral diseases. A much less common problem, but one that causes significant discomfort, is oral mucositis.

Cold sores (fever blisters) are caused by the herpes simplex type 1 virus (herpes simplex labialis) and are most commonly found at the junction of the mucous membrane and the skin of the lips or nostrils, although they can occur inside the mouth, especially affecting the gums and roof of the mouth. It is estimated that at least half of all Americans ages 20 to 40 years have had fever blisters. Most victims were infected before 5 years of age. About half of patients will develop recurrent outbreaks of the lesions, often in the same location, separated by latent periods. The recurrence rate and extent of lesions are highly variable. Patients often predict when an outbreak may occur because of predisposing factors, such as systemic illnesses accompanied by fever, cold (hence the names fever blisters and cold sores), or flu, menstruation, extreme physical stress and fatigue, or sun and wind exposure. Chemotherapy or radiation therapy that depresses the immune system also triggers cold sores.

Patients often report that a flare-up of the sores is preceded by a prodrome of burning, itching, and numbness in the area where the lesion develops. The lesions first become visible as small, red papules that develop into fluid-filled vesicles (blisters) 1 to 3 mm in diameter. Smaller lesions often coalesce into larger lesions. Pain is intense, fever may be present, and increased salivation and mouth odor occur. Often, the glands in the neck are swollen because of the body’s response to infection. Over the next 10 to 14 days, a crust develops over the top of many coalesced, burst vesicles; the base is erythematous. The liquid from the vesicles contains live virus that is contagious if transferred to other people by direct contact (e.g., kissing). If pus develops in the vesicles or under the crust of a cold sore, a secondary bacterial infection may be present and should be evaluated for antibiotic therapy.

Canker sores, also known as recurrent aphthous stomatitis (RAS), affect 20% to 50% of people in the United States. The exact cause is unknown, but precipitating factors appear to be stress and local trauma (e.g., chemical irritation, toothbrush abrasion, irritation from orthodontic braces, biting the inside of the cheeks or lips). The lesions are not viral infections as was once thought and they are not contagious. There appears to be a familial factor, as well as nutritional, emotional, and physiologic factors. They can develop at any age and affect both genders in equal numbers. Canker sores can appear as ulcers 0.5 to 2 cm in diameter on surfaces that are not attached to bone, such as the tongue, gums, or inner lining of the cheeks and lips. The lesion is usually gray to whitish yellow, with an erythematous halo of inflamed tissue surrounding the ulcer crater. Lesions do not form blisters and usually do not grow together. Patients may experience a single lesion or as many as 30 or more at one time. The lesions can be painful and can inhibit normal eating, drinking, talking, and swallowing, as well as oral hygiene. There are usually no swollen lymph glands or fever unless the sore becomes secondarily infected. Most canker sores last 10 to 14 days and heal without scarring.

Candidiasis is a fungal infection caused by Candida albicans, the most common organism associated with oral infections. It is often called “the disease of the diseased” because it appears in debilitated patients and patients taking a variety of medicines. The most common predisposing factors are physiologic (e.g., early infancy, pregnancy, old age), diabetes mellitus, malnutrition, malignancies, and radiation therapy. Medicines that predispose a patient to candidiasis are those that depress defense mechanisms (e.g., immunosuppressants, corticosteroids, cytotoxics, broad-spectrum antibiotics) and those that cause xerostomia (e.g., anticholinergics, antidepressants, antipsychotics, antihypertensives, antihistamines).

There are several forms of candidiasis, but the most common is the acute, pseudomembranous form that is often referred to as thrush. It is characterized by white milk curd–appearing plaques attached to the oral mucosa. These plaques usually can be easily detached, and erythematous, bleeding, sore areas appear beneath them. Thrush is most common in infants, pregnant women, and debilitated patients. Treatment requires local or systemic therapy with antifungal agents, such as nystatin (Mycostatin) suspension, or clotrimazole troches (see discussion of antifungal agents in Chapter 46).

Mucositis (as termed stomatitis) is a general term used to describe a painful inflammation of the mucous membranes of the mouth. It is commonly associated with chemotherapy and radiation therapy. Mucositis develops 5 to 7 days after antineoplastic therapy or radiation therapy has been administered. The sores are erythematous ulcerations intermixed with white patchy mucous membranes. Candidal infections are often present.

Commonly used scales and criteria used to standardize the evaluation of mucositis and therapy include the World Health Organization Oral Mucositis Scale (Table 32-1); the Radiation Therapy Oncology Group (RTOG) Acute Radiation Morbidity Scoring Criteria; the Western Consortium for Cancer Nursing Research (WCCNR) stomatitis staging system; and the National Cancer Institute–Common Toxicity Criteria (NCI-CTC). Mucositis is often a primary complaint associated with cancer therapy because it can diminish a patient’s perception of quality of life. It can be severely debilitating, with pain and difficulty in swallowing, eating, drinking, and talking.