Diagnosis of infectious nail diseases, in particular onychomycosis, is often difficult due to the clinical similarity of infectious and non-infectious lesions, the possibility of their combination and the high probability of false-negative laboratory test results. Optical coherence tomography (OCT) is a non-invasive high-resolution method for visualization of biological tissues approaching in terms of information content to histological one. The use of OCT makes it possible to assess the components of the nail apparatus in normal conditions and under certain pathological conditions.
OBJECTIVE
To study the possibility of the OCT clinical use for the diagnosis of certain nails’ infectious diseases.
MATERIAL AND METHODS
The study included 47 patients with isolated lesions of the nail plates of the feet and/or hands with suspected onychomycosis who underwent an examination of the nail apparatus which included microscopic examination using a 20% potassium hydroxide solution, a culture study using the Sabouraud universal nutrient medium, research using the Candiselect test system, as well as OCT. During OCT an optically coherent computerized visualizer-topograph was used for non-invasive study of the internal structure of human surface tissues «VOK» (Federal Research Center Institute of Physics of the Russian Academy of Sciences, Russia).
RESULTS
Tomographic signs of onychomycosis were detected in 35 patients including 5 patients with negative results for dermatophytes. In 5 of them the OCT signs of onychomycosis and psoriasis of the nail plates were found. In 7 patients with suspected onychomycosis and negative results of the study for dermatophytes during the OCT study there were signs of candida nail lesions (laboratory examination confirmed the diagnosis in 5 cases). Anti-candidiasis therapy in these patients had a positive effect including cases with negative laboratory test results. In 5 patients with negative results of tests for dermatophytes and candida the use of OCT made it possible to establish a diagnosis of pseudomonas lesion and provide adequate therapy.
CONCLUSION
Optical coherence tomography can be effectively used in the complex diagnosis of nails’ infectious diseases and provide significant assistance in establishing the diagnosis of false-negative results of laboratory tests for dermatophytes and candida as well as in combined fungal and psoriatic pathology of the nail apparatus.
