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ОглавлениеCandidiasis
Definition
Candidiasis is the most frequent fungal infection of the oral cavity.
Etiology
Candida albicans is the most common Candida species to cause oral candidiasis. Other species such as C. glabrata. C. tropicalis, C. krusei, C. parapsilosis, C. dubliniensis can cause infections though less frequently. Candida species are normally present on mucocutaneous body surfaces, and several local and systemic predisposing factors are necessary to develop infection with clinical symptoms and signs.
Classification
Oral candidiasis is clinically classified as primary and secondary. Primary candidiasis includes several clinical forms such as pseudomembranous, erythematous, nodular, and Candida-associated lesions (angular cheilitis, median rhomboid glossitis, denture stomatitis). Secondary candidiasis includes chronic mucocutaneous and Candida-endocrinopathy syndrome. Systemic candidiasis is less common than superficial Candida infection, but it is an increasing problem in immunocompromised patients. Candidemia is now recognized as the fourth most important nosocomial bloodstream infection.
Main Clinical Features
The oral mucosa is the most common site of superficial candidiasis. However, the vagina, glans penis, skin, and nails may also be involved.
Pseudomembranous (Thrush)
•The most common form of oral candidiasis, usually acute. It appears as creamy whitish spots or plaques, which usually can be detached. The lesions may be localized or generalized. Burning, dryness, loss of taste, and pharyngeal dysphagia are common symptoms
Erythematous
It appears as erythematous patches usually on the dorsum of the tongue and palate. This form is common in HIV-infected patients and in patients on antibiotics. Burning is a common symptom
Nodular
A chronic form of candidiasis that appears as white, firm, raised plaques that cannot be detached. The lesions are usually asymptomatic
Candida-Associated Lesions
Angular cheilitis: red, fissured crusts with or without erosions. Whitish spots or plaques may be present
Median rhomboid glossitis: reddish smooth or nodular surface on the midline of the dorsum of the tongue
Denture stomatitis: diffuse erythema and edema of the mucosa underneath a denture
Secondary Forms
Chronic mucocutaneous candidiasis: chronic oral lesions, skin and nail lesions as well. Classically the oral lesions are generalized Candida-endocrinopathy syndrome: severe oral. skin, and nail lesions associated with endocrinopathies appear early in life from 4-6 years of age
Diagnosis
The diagnosis of candidiasis is usually based on clinical criteria. Direct smear microscopic examination with potassium hydroxide and culture are helpful. Biopsy and histopathologic examination may also be useful in some cases.
Differential Diagnosis
•Leukoplakia
•Hairy leukoplakia
•Lichen planus
•Lupus erythematosus
•Mucous patches of secondary syphilis
•White sponge nevus
•Uremic stomatitis
•Cinnamon contact stomatitis
•Chemical burns
•Traumatic lesions
•Furred tongue
Treatment
Basic Guidelines
•Elimination of systemic and/or local predisposing factors are important to avoid recurrences.
•Maintenance of high level of oral hygiene and reduction of the Candida reservoir in the mouth, esophagus, and genitalia.
•Accurate diagnosis of the clinical form of oral candidiasis is important.
•Topical or systemic therapy should be used depending on the form and severity of the disease.
•The majority of the available antifungal drugs target the synthesis of ergosterol. a constituent of the fungal cell membrane.
Suggested Therapies
Systemic Treatment
Systemic azoles are the drugs of choice. Itraconazole capsules 100 mg/day or fluconazole 100 mg/day for 1-2 weeks are usually effective for acute pseudomembranous candidiasis and Candida-associated lesions. The erythematous and nodular forms usually need therapy for 2-4 weeks. The secondary forms need long-term administration of the above drugs in a close of 100-200 mg/day for 1-3 months.
Ketoconazole capsules 200 mg twice daily for 1-4 weeks, depending the form of the disease, may also be used. In patients with resistant Candida species, in neutropenic patients, or in patients with malignancies, transplants, and AIDS, itraconazole oral solution 2.5-5 mg/kg per day is indicated. Ketoconazole has significantly greater bioavailability than itraconazole and, in addition, has a topical effect; therefore it may convey additional benefits over other oral agents in the treatment of oral candidiasis. It must be remembered that successful systemic treatment of oral candidiasis often depends on correction or treatment of the predisposing factors.
The use of systemic azole derivatives can be impaired by interference with gastric pH. by interactions with other drugs such as rifampicin, acyclovir, cyclosporine. phenytoin. H2-antagonists, terfenadine. astemizole. or by the emergence of resistant or less susceptible strains of Candida.
Clinicians should avoid systemic azoles in patients with severe liver disease and during pregnancy. The most frequent side effects of itraconazole and fluconazole are gastrointestinal symptoms (nausea, vomiting, diarrhea, epigastralgia)and rash.
Topical Treatment
Nystatin oral suspension four times a day or miconazole oral gel 5 ml four times a day for 1-2 weeks is indicated, particularly for oral acute pseudomembranous candidiasis in infants or children or for adults where systemic treatment is not indicated. Angular cheilitis (perlèche) is treated with topical antifungal ointments.
Future Therapies
Third generation triazoles (voriconazole, posa-conazole. ravuconazole), echinocandins (main representative caspofungin) and the incorporation of nystatin into liposomes are being investigated as possible alternative treatments.
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