Usefulness of culture test and direct examination for the diagnosis of oral atrophic candidiasis

Background  Culture test and direct microscopy, which are currently used in the diagnosis of oral candidiasis, can yield false-negative results.
Methods  Forty patients with atrophic candidiasis of the tongue were evaluated. The diagnosis was confirmed by a favorable outcome consisting of tongue pain improvement and regeneration of filiform papilla after antifungal treatment in all patients. Specimens were examined by fungal culture and direct microscopy following rapid staining; the usefulness of these procedures for diagnosis was reevaluated retrospectively after treatment.
Results  In the culture test, 30 patients (75.0%) were positive for candidal species, most of which were confirmed to be Candida albicans . Twenty-three (57.5%) were positive for pseudohyphae of fungi on direct examination. Twenty-two (55.0%) were positive and nine (22.5%) were negative for both. With regard to the diagnosis of oral atrophic candidiasis, these examinations revealed false-negative results of 25% in the culture examination and 42.5% in the direct examination.
Conclusion  Careful clinical observation of the patient for signs, such as prolonged disease duration, pain on eating, and no benefit from topical steroid treatment, and cytologic examination are important in the diagnosis of this disease.