Mouth infections

• ANATOMY OR SYSTEM AFFECTED: Lips, mouth, tissue, tongue

Definition

Infections of the mouth can range from minor to severe to life-threatening. They occur when the natural protective mechanisms of the oral cavity are breached. Organisms that cause mouth infections are those that normally reside in the oral cavity and those that have been introduced from other sources.

The healthiness of a person’s immune system, the integrity of natural barriers, and the infectious capacity of the organism determine if an infection will occur. Resident and foreign mouth microorganisms can infect the tongue, gums, the roof of the mouth, tooth-supporting structures, and the inner lining of the cheeks and lips (buccal mucosa). These infections are most often localized to the mouth but can also spread to other areas of the body, including the heart. Mouth infections are classified as fungal, viral, or bacterial.

Causes

Fungal infections of the mouth include the infections listed here.

Superficial oral infections. The most common fungus that causes mouth infections is the Candida species. This fungus normally resides in the mouth and invades the protective barriers when opportunities arise. The most common species are C. albicans, C. galbrata, and C. tropicalis. The resulting fungal infection, thrush or pseudomembranous candidiasis, appears as cream-colored patches on the tongue, buccal mucosa, or palate. Wiped-off patches reveal surface redness. Hyperplastic candidiasis is a chronic superficial infection that cannot be easily wiped away. Erythematous candidiasis appears as red patches most commonly found on the roof of the mouth or under the tongue. Angular cheilitis (perleche) affects the corners of the mouth, causing redness and cracking of the skin.

Noncandidal fungal infections. These fungal infections tend to deeply penetrate the mucosal layers of the mouth. They have the potential to cause damage to oral tissue, and their presence typically indicates that the body has other infections. Aspergillosis is the second most common fungal mouth infection; it is caused by the Aspergillus group of fungus. Aspergillosis is evidenced by ulcers on the roof of the mouth. The most common species of Aspergillus that cause mouth disease are A. flavus, A. terreus, and A. fumigates. Histoplasmosis (Histoplasma capsulatum), cryptococcosis (Cryptococcus neoformans), blastomycosis (Blastomyces dermatitidis), zygomycosis (Rhizopus), geotrichosis (Geotrichum capitatum), and coccidioidomycosis (Coccidioides immitis) are rare fungi that cause infections in the deep layers of the mouth. These fungi can cause life-threatening illnesses. All but geotrichosis appear as ulcers or nodules on the interior walls of the cheek, tongue, or roof of the mouth. Much like Candida, geotrichosis infections appear as cream-colored patches.

Bacterial mouth infections include the infections listed here.

Oral mucosal infections. Although hundreds of types of bacterial organisms can potentially cause oral mucosal infections, there are several that are most common. Streptococcus, Bacteroides, Peptostreptococcus, oral anaerobic bacteria, and gram-negative bacilli are the most common organisms that cause oral mucosal infections.

Gangrenous stomatitis. Gangrenous stomatitis, also known as noma, is a rapidly spreading infection of oral and facial tissues typically found in the presence of debilitating illnesses. Caused by multiple bacteria, this infection begins as a small vesicle found on the gum. Ulceration of the deeper layers causes eventual destruction of the mouth, facial tissues, and bones. Several types of bacteria can cause this polymicrobial disease, but the most commonly isolated organisms are Fusobacterium nucleatum, Borrelia vincentii, and Prevotella melaninogenica.

Oral syphilis. Syphilis is a sexually transmitted disease caused by the bacterium Treponema pallidum. Oral lesions are a manifestation of this systemic disease. In the primary form of the disease, ulcers of the lips and tongue develop. Secondary syphilis rarely produces oral ulcerations and is most likely to manifest as flat or raised red patches on the roof of the mouth or tongue. Nodular lesions are rare and can be mistaken for oral cancer. Tertiary syphilis can give rise to a rare mouth lesion called gumma. Gumma is a painless mass that is surrounded by inflamed tissue and forms on the tongue or roof of the mouth. Uncommonly, gumma may erode into oral blood vessels.

Oral tuberculosis. Caused by Mycobacteria tuberculosis, oral tuberculous lesions are rare. They may present as single ulcers or as a small mass on the gums or tongue. Difficult to diagnose, oral tuberculosis may invade and cause destruction to the bones of the face.

Bacterial salivary gland infections (sialadenitis). Located in the cheeks at the angle of the jaw and under the tongue, the salivary glands may become infected with bacteria, causing pain and swelling. Although dozens of bacteria can cause salivary gland infections, the most common are Staphylococcus aureus, Prevotella, Porphyromonas, Fusobacterium, and Peptostreptococcus.

Bacterial gingivitis. Gingivitis is a common gum infection caused by poor oral hygiene. Most commonly caused by Streptococcus and Actinomyces, bacterial gingivitis causes discoloration and thickening of the gums. A more severe form of gingivitis known as acute necrotizing ulcerative gingivitis, or Vincent’s angina, causes erosive lesions of the gums. Prevotella, Fusobacterium, Tannerella, and Treponema are the most common varieties of bacteria that cause this form of gingivitis.

Bacterial periondontitis, periodontal abscess, and pericoronitis. Like gingivitis, poor oral hygiene can lead to bacterial infections of the deep supporting structures of the teeth. Although periodontitis is typically an inflammatory disease, a more destructive form of periodontitis caused by bacteria infiltration can develop, causing the breakdown of the supporting structures of the teeth and, ultimately, tooth loss. Pericoronitis is an infection under the gum flaps of wisdom teeth or nonerupted teeth. Bacteria can become trapped under the gums and cause local infection or an abscess. The most common bacteria causing bacterial periodontitis and pericoronitis are Actinobacillus, Treponema, Prevotella, Porphyromona, and Tannerella.

Viral mouth infections include the infections listed here.

Human herpes viral infections. Herpetic gingivostomatitis (oral herpes) is the classic cold sore caused by human herpetic virus 1 (HHV-1). Presenting as small vesicles on lips, gums, or the roof of the mouth, HHV-1 can be isolated in about 80 percent of adults. Recurrent infections are triggered by emotional stress, sunlight, and systemic illnesses. Herpetic stomatitis is a condition in young children that likely represents the initial herpes simplex infection, causing fever and blisters on the tongue or cheeks. Genital herpes (HHV-2) causes lesions similar to HHV-1, although it is less commonly found in the oral cavity.

Chickenpox and shingles are a result of HHV-3. This vesicular rash occurs primarily in children aged three to six who have not been vaccinated for the varicella virus and who are at risk for chickenpox. Shingles or herpes zoster is the reactivation of the disease in adults, especially persons aged sixty and older. Herpes zoster rarely occurs in those vaccinated with the varicella vaccine. The vesicular lesions of shingles occur unilaterally and localize in an area of the skin corresponding to a spinal nerve.

Mononucleosis is an infectious disease caused by Epstein-Barr virus or HHV-4. It infects the salivary glands, causing pain and swelling. Occasionally, red spots (petechiae) on the roof of the mouth are seen. Oral hairy leukoplakia is also caused by HHV-4. This disease manifests as white patches on the sides of the tongue.

Cytomegalovirus infection caused by HHV-5 is typically found in immunosuppressed persons. Although most commonly asymptomatic, cytomegalovirus infection can cause swelling of the salivary glands and ulcerative lesions of the oral mucosa. Oral Kaposi’s sarcoma (KS) shows raised, purple-colored tumors and is caused by HHV-8.

Human papillomavirus (HPV).Condyloma acuminate is primarily caused by human papillomavirus (HPV)-6 and HPV-11. Condyloma, which causes clusters of warty, pink, or whitish lesions on the tongue, roof of the mouth, and gums, is seen primarily in the genital area. Focal epithelial hyperplasia, or Heck disease, is caused by HPV-13 and HPV-32. These contagious lesions manifest as multiple, smooth nodules and are found most often on the buccal mucosa. Verruca vulgaris is caused by a variety of HPVs, but HPV-16 is the most common cause. These contagious lesions manifest as hard, rough, pointy clusters of white lesions and are found on the tongue, gums, and the roof of the mouth.

Coxsackie virus causes two primary types of disorders in the mouth, namely hand, foot, and mouth disease and herpangina. Hand, foot, and mouth disease manifests as multiple vesicles surrounded by a red base and are found on the cheeks, tongue, and the roof of the mouth. Herpangina initially appears as painful small red lesions, which then become vesicles and, eventually, ulcers. They are found primarily on the cheeks.

Caused by the Rubulavirus genus, mumps are a viral infection of the salivary glands of the cheek (parotid glands). It is seen primarily in unvaccinated or “failed” vaccinated children aged five to nine. Infected children have the characteristic chipmunk appearance because of swollen parotid glands. Caused by the Morbillivirus genus, measles is a highly infectious disease typically seen in unvaccinated or failed vaccinated children less than five years of age. Koplik spots are small, white lesions found on the buccal mucosa during the initial stages of measles infection. Rubella is caused by the Rubivirus genus. This contagious disease rarely causes mouth infections. There are, however, cases reported in the literature in which children have developed red spots on the buccal mucosa.

Risk Factors

Oral fungus infections are opportunistic diseases that mainly occur because of compromised defense mechanisms. Medications such as corticosteroids, broad-spectrum antibiotics, tricyclic antidepressants, and immunosuppressive agents (chemotherapy) can cause superficial oral infections. Additionally, a high carbohydrate diet, iron deficiency anemia, and ill-fitting dentures have been implicated in causing oral candida. The noncandidal infections that cause deeper mouth infections usually occur because of systemic diseases that cause compromised immune systems. Systemic diseases such as diabetes, thyroid disease, leukemia, advanced-stage cancer, and acquired immunodeficiency syndrome (AIDS) allow fungi to grow in the oral cavity. Older adults, pregnant women, and infants are also at risk of oral fungal infections because of compromised or inadequate immune responses.

Bacterial oral mucosal and salivary gland infections, like fungal infections, generally arise because of defective immune systems. The most common cases involve persons who are undergoing chemotherapy or radiation therapy. Inflammation of the mucosal surfaces (mucositis) causes a breakdown of the protective surfaces, opening the door for oral bacteria. Because of compromised systemic defenses in these diseases, bacterial infections develop. Malnutrition, dehydration, and unsanitary conditions have been shown to contribute to these infections.

Gum and periodontal infections arise because of poor oral hygiene. Immunosuppressive drugs, smoking, and systemic diseases such as diabetes, kidney failure, and cancer increase the severity of disease.

Viral mouth infections can be contracted from person to person through saliva droplets. Although any person may be at risk for contracting a virus, the susceptibility and severity of the disease is largely dictated by the health of a person’s immune system. Chronic disease and medications resulting in diminished immunity may increase the prevalence and severity of the infection. Although there are several forms noted worldwide, Kaposi’s sarcoma (KS) is mostly seen in persons infected with the human immunodeficiency virus (HIV) in the United States. Organ transplant recipients are also known to develop KS.

Symptoms

Infections of the mouth may cause mucosal redness, ulcerations, bad breath, oral bleeding, altered taste sensation, and facial swelling. More severe symptoms include mouth pain, difficulty swallowing, swollen lymph nodes of the neck, fever, fatigue, and destruction of facial tissue. Respiratory, gastrointestinal, urinary, and cardiac symptoms can result from the spread of bacteria to internal organs.

Screening and Diagnosis

The superficial fungal infections such as those caused by Candida usually can be diagnosed through examination by a health care provider. Observation is typically enough to make the diagnosis. In unclear cases, a swab of the lesions can be sent to a laboratory for identification. Deep infections should be checked through biopsy. A culture of fungal lesions helps to direct treatment because antifungal sensitivities are established through this mechanism.

Diagnosis of a mucosal bacterial mouth infection is achieved by a swab or biopsy of the lesions. Bacterial and viral infections of the salivary glands, gums, or periodontal structures are typically made by observation. Imaging studies such as a computed tomography (CT) scan, magnetic resonance imaging (MRI), or ultrasound may be needed to determine the location of infected structures or of abscesses. In severe infections, rapid determination of the type and location of infection is critical to effective treatment.

Most viral mouth infections can be diagnosed by observation, but a biopsy or smear of the lesion may be required to identify the virus. Also, antibody levels in the blood may assist in confirming the diagnosis of some viral infections.

Treatment and Therapy

Given that mouth infections can be quite painful, symptomatic relief is important. Analgesics such as acetaminophen and ibuprofen are used for mild to moderate pain. Narcotic pain medication may be needed for severe pain. Oral topical anesthetics such as dyconine and lidocaine can provide temporary relief of pain.

Superficial oral candidal infections are treated with topical antifungal medications. Nystatin and clotrimazole lozenges, mouth rinses, and creams are typically sufficient. Severe or resistant cases of oral candidiasis are treated with intravenous antiviral medications. Fluconazole, amphotericin B, miconazole, and itraconazole were the first antifungal medications available. Newer antifungal medications such as caspofungin, flucytosine, posaconazole, and voriconazole cause less side effects and more specificity of action against fungal species. Most important in treating fungal infections is the treatment of underlying diseases.

Treatment of uncomplicated bacterial infections of the oral mucosa, salivary glands, gums, and periodontal structures is primarily directed at symptomatic relief. Mouth rinses containing antiseptic solutions or anesthetics are helpful in reducing pain and healing time. Complicated infections are treated with the removal of infected or damaged tissues and with antibiotics that are specific to the organism causing infection.

Although most viral oral lesions resolve without treatment, a few exceptions exist. Genital herpes, shingles, and cytomegalovirus are treated with antiviral agents. Oral hairy leukoplakia and condyloma can be treated with topical gels that break down the lesions. Large condyloma, epithelial hyperplasia, and Verruca vulgaris are treated by excision. KS is treated by correction of the underlying immunosuppression with highly active antiretroviral therapy (HAART). Many infected persons, however, need radiation or chemotherapy.

Prevention and Outcomes

The prevention of all mouth infections is achieved largely through the implementation of adequate oral hygiene and sanitary practices, especially when systemic disease is present. One should brush teeth and tongue twice daily; floss once a day; use antiseptic mouthwash once a day; rinse mouth after using antibiotics or other oral medications; visit a dentist for examinations and teeth cleaning twice yearly; wash hands frequently, especially after coming into contact with dirty objects and surfaces; avoid close contact with persons with communicable diseases; avoid or limit alcohol and sugar intake; stop smoking; consider the use of preventive antifungal, antibacterial, or antiviral treatments (persons with compromised immune systems); and complete vaccinations recommended by a physician.

Bibliography

Chow, Anthony W. “Infections of the Oral Cavity, Head, and Neck.” Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, edited by Gerald L. Mandell, et al., 8th ed., Churchill Livingstone/Elsevier, 2017.

Epstein, Joel B. “Mucositis in the Cancer Patient and Immunosuppressed Host.” Infectious Disease Clinics of North America, vol. 21, no. 2, 2007, pp. 503–22.

Gordon, Sara C., et al. “Viral Infections of the Mouth.” Medscape, 30 May 2018, emedicine.medscape.com/article/1079920-overview. Accessed 20 Oct. 2024.

Scully, Crispian, and Maria R. Sposto. “Noncandidal Fungal Infections of the Mouth.” Medscape, 23 Nov. 2022, emedicine.medscape.com/article/1077685-overview. Accessed 20 Oct. 2024.

Withe, Meara. "3 Common Causes of Mouth Infections and How to Treat Them." Medical News Today, May 2024, www.medicalnewstoday.com/articles/mouth-infections. Accessed 20 Oct. 2024.