4: Bacterial, Viral, Fungal, and Other Infectious Conditions

4 Bacterial, Viral, Fungal, and Other Infectious Conditions

Any infection that occurs in any other part of the body may manifest in the mouth, including mycobacterial, treponemal, and bartonellal infections, although they are uncommon and rarely occur initially in the mouth. In many parts of the world, mycobacterial and syphilitic infections are on the rise. Polymicrobial bacterial infections in the mouth are the most common and are generally not subject to biopsy because most of these are related to dental caries and periodontal infections. Actinomycosis is one bacterial infection that is seen on biopsy with some frequency.


There are five common areas of involvement—cervical-facial, pulmonary, ileocecal, genitourinary, and central nervous system. The less well known and yet fairly common infection involving the jawbones and oral soft tissues is discussed here.

Candidiasis (Candidosis)

This is the most common fungal infection in the mouth.

Clinical Findings

Etiopathogenesis and Histopathologic Features

Lesions are caused by Candida albicans or other species when the flora in the mouth is altered because of hyposalivation, use of antibiotics or corticosteroids, and immunosuppression. Because Candida is a commensal in approximately 20% of the population, a positive culture in and of itself is not diagnostic for candidiasis. Scraping the lesion and use of either potassium hydroxide or standard cytology stains to identify hyphae is diagnostic, as is a biopsy.

Infectious Granulomatous Inflammation

Clinical Findings

Concomitant systemic or skin involvement is usually noted and history is very important in the diagnosis.

Ulcerated and indurated, granular, vegetating nodules of the palate and gingiva are common oral presentations, and there is usually concomitant lung, nodal, and skin disease; immunocompromised patients are particularly susceptible to disseminated disease.

Coccidioidomycosis caused by Coccidioides immitis is endemic in California and the southwest United States.

Histoplasmosis caused by Histoplasma capsulatum is endemic to the Ohio-Mississippi Valley and is found in the soil and in bird and bat droppings; patients taking tumor necrosis factor-α inhibitors are prone to contracting this infection, as well as coccidioidomycosis in endemic areas.

Paracoccidioidomycosis caused by Paracoccidioides brasiliensis, a soil saprophyte, is common in South America where 80% to 90% of cases are chronic (Fig. 4-8).

Phycomycoses (order Mucorales, genera Rhizopus, Absidia, Mucor, and Rhizomucor) and aspergillosis (Aspergillus fumigatum or A. flavus) appear black, necrotic and/or fungating, resembling malignancy; rhinocerebral phycomycosis is increasing in frequency and is often seen in patients with diabetes (especially if ketoacidotic), neutropenia, malignancy, and post–organ transplantation; mortality rate is 60% to 90%; aspergillosis appears similar but tends to affect immunocompromised patients (such as those with leukemia) rather than those with diabetes; both primarily affect the palate and maxilla, and vascular involvement leads to necrosis.


FIGURE 4-8 Oral paracoccidioidomycosis: ulcerated and erythematous lesion of palate.

(Courtesy of Dr. Roman Carlos, Guatemala City, Guatemala.)

Jan 12, 2015 | Posted by in Oral and Maxillofacial Pathology | Comments Off on 4: Bacterial, Viral, Fungal, and Other Infectious Conditions
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