Kinetics of oral colonization by Candida spp. during topical corticotherapy for oral lichen planus

Oral candidiasis is an important side effect of topical corticotherapy. The purpose of this study was to assess oral mucosa colonization by five Candida species during topical corticotherapy and to investigate Candida spp. pathogenicity and in vitro susceptibility to fluconazole and amphotericin B.

Oral swabbing samples from 11 erosive oral lichen planus (OLP) patients were collected before (day 0) and at days 7 and 30 of topical corticotherapy. Conventional methods for identification and quantification of Candida species, quantitative PCR (qPCR), pathogenicity tests and in vitro susceptibility to fluconazole and amphotericin B assays were performed.

Candida albicans was the most prevalent species in the oral mucosa after corticotherapy. Increased number of colony-forming units (CFU) and Candidaalbicans DNA copies were observed at day 30 of corticotherapy, despite no clinical evidence of candidiasis in any patient. Colony-forming units’ count of Candida species was less sensitive than qPCR, but both methods positively correlated. No resistance to fluconazole or amphotericin B was observed.

Topical corticoid used for oral erosive lichen planus treatment was associated with increase in Candida spp., in particular, C. albicans, in the oral cavity, independent of clinical manifestation of the disease.