22nd April 2024

Oral infections

Fungal Disease of the mouth

Candidiasis is a fungal infection that is caused by the overgrowth of Candida species, the most common of which is Candida albicans. While Candida naturally resides on the skin and mucous membranes without causing harm in most individuals, certain conditions can lead to its proliferation and subsequent infection. The severity and manifestations of candidiasis can vary depending on the immune status of the affected individual, with immunocompetent and immunocompromised individuals presenting distinct clinical phenotypes. Patients with dentures or diabetes can be put at an augmented risk of oral candida. Immunocompetent individuals are capable of mounting an effective defence against Candida. In these individuals, candidiasis characteristically occurs in localised areas such as the oral cavity, known as oral thrush, as well as the vaginal area in women. Symptoms of infection may include white patches or plaques, pruritus, and discomfort in the affected areas. Immunocompetent individuals with candidiasis usually respond well to treatment with topical or oral antifungal agents, and the infection is generally self-limiting. Immunocompromised individuals allow Candida to invade deeper tissues and organs, leading to invasive candidiasis. This condition can occur in patients with underlying medical conditions such as HIV/AIDS, cancer, organ transplantation, or those receiving immunosuppressive therapy. Invasive candidiasis can manifest as bloodstream infections (candidemia), disseminated infections, or localised infections in specific organs such as the kidneys, liver, or lungs. Disseminated candidiasis requires intravenous fungal agents as well as a multidisciplinary approach involving infectious disease specialists, microbiologists, and other healthcare professionals, to guide appropriate treatment and monitor the response to therapy.

Viral and Bacterial Infections of the Mouth

Herpes Simplex Virus (HSV) infections are caused by two types of viruses: HSV-1 and HSV-2. HSV-1 primarily causes oral infections, while HSV-2 is associated with genital infections, although both viruses can infect either location. HSV-1 infections can be transmitted through direct contact with oral secretions. HSV infections in the mouth habitually present as painful fluid-filled blisters or ulcers on the lips, tongue, gums, or inside the cheeks. These lesions are often accompanied by local inflammation, discomfort, and mild systemic symptoms, such as fever and malaise. The primary infection can be severe, with multiple lesions and more systemic symptoms, while recurrent infections tend to be milder. Diagnosis of oral HSV infections is based on clinical presentation and can be confirmed through viral culture, polymerase chain reaction testing, or serological assays. Management focuses on symptomatic relief and includes antiviral medications, such as acyclovir, which help to reduce the duration and severity of outbreaks. Coxsackievirus infections can also lead to various oral manifestations, including herpangina and hand, foot, and mouth disease (HFMD). Herpangina presents as small, painful ulcers on the back of the throat, while HFMD results in ulcers on the tongue, gums, and inner cheeks.

Bacterial infections in the oral cavity, particularly dental abscesses, are common and can lead to significant oral health issues. Dental abscesses are localised collections of pus that form within the teeth or surrounding tissues. These infections, if left untreated, can result in severe pain, swelling, and potentially systemic complications such as infective endocarditis. Dental abscesses typically originate from dental caries (tooth decay) or periodontal disease. Streptococcus mutans, a common bacterium found in dental plaque, is frequently associated with the initiation and progression of dental caries. As caries progress, bacteria can penetrate the tooth structure and infect the dental pulp, leading to the formation of an abscess. Diagnostic imaging techniques, such as dental X-rays or orthopantomogramme may be employed to assess the extent of the infection and identify any underlying dental pathology. Antibiotics are commonly prescribed to control the infection.

References

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• Kullberg BJ, Arendrup MC. Invasive candidiasis. N Engl J Med. 2015;373(15):1445-1456
• Pappas PG, Kauffman CA, Andes DR, et al. Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2016;62(4):e1-e50
• Scully C. Orofacial Herpes Simplex Virus Infections—Update on Current Concepts of Viral Pathogenesis and Disease Management. Oral Surg Oral Med Oral Pathol Oral Radiol. 2019;127(4):340-350. doi:10.1016/j.oooo.2018.12.004.