Frequency of Trichophyton rubrum in tinea capitis.

Trichophyton rubrum has led to unprecedented worldwide suppression of other dermatophytes which had been predominant earlier as a causative agent of superficial dermatomycoses. In tinea capitis on the other hand, several other species of Trichophyton or Microsporum are dominant depending on the region or continent. Tinea capitis caused by T. rubrum is a rare event worldwide. Occasional concentrations may be explained by several cases occurring by chance in one family or community. The relative frequency of this causative agent in tinea capitis in children is under 1%. In adults, however, where tinea capitis occurs very infrequently indeed, the incidence of T. rubrum appears to exceed 10%. Apart from two studies from India, one from Iran, two from Portugal and observations from Germany, which in the first country report of around 30% of all cases published, while the others document some 10% each, there are not only any conspicuous, unequivocal concentrations at all. Increased frequency of T. rubrum in this clinical picture has not been easily recognizable over the last decades due to low absolute case numbers.