Lesiones ungueales y cutáneas por Scytalidium dimidiatum en Medellín (Colombia), 1990-1999. Presentación de 128 casos y revisión del problema del nombre del agente

Aim: To review the problem of the name of the agent, and to report epidemiologic features of 128 cases of nail and skin lesions caused by S.dimidiatum. Design: Descriptive study, partly retrospective (1990-1996) and partly prospective (1997-1999). Reference frame: Until recently there were problems with the nomenclature of the agent but now there exist arguments for solving the difficulties, and that was the first objective of our work: to present such arguments and to indicate the correct use of the different names. On the other hand, the importance of S. dimidiatum as agent of human lesions is increasing. This report is restricted to nail and skin lesions, of which we found 128 cases between 1990 and 1999. Methods: Laboratory records were reviewed and doubts were solved by means of consensus criteria. Mycological diagnostic criteria were established. Statistical analysis was performed with the Epi Info program, version 6.04; it consisted mainly of evaluating the association of variables with chi2 and in comparing positions of continuous and organized data according to their magnitude by means of the Kruskal-Wallis H test. Results: The different names of the agent should be used in precise situations, that are described. A total of 128 specimens was studied from which S. dimidiatum had been isolated in culture: 102 were from nails (92% from the feet) and 26 from the skin (73% interdigital from feet). Epidemiologic features of a typical case of nail lesion due to S. dimidiatum indicate that in 41% the patients was an woman, 21-49 year-old, who uses “risk” shoes, presents hyperhydrosis and practices a sport. On the other hand typical epidemiologic features of a skin lesion due to S. dimidiatum are similar to these the only difference being the predominance of males (69%). Direct examination was positive in 97% of the cases and the most frequently found structures were threadlike hyphae charateristic of dermatophytes (72%), followed by sinous fungal hyphae alone or with chlamydospores (21%) and yeast cells alone or with pseudohyphae (5%). There was no significant difference between the results of nail and skin