Wood's light in Microsporum canis positive patients

In 64 patients with culturally proven Microsporum canis infections, Wood's light examination was performed. In 30 patients (47%) the characteristic fluorescence correlated with the cultural findings, whereas in the remaining 34 patients (53%), Microsporum canis was isolated, although Wood's light examination was negative. Of the 30 positive and 34 negative cases eight patients of each group had been pre-treated. From the results presented, Wood's light examination has a poor sensitivity in cases of Microsporum canis-infections.