MICROSPORUM-CANIS SCALP RINGWORM - ITS PRIMARY OR SECONDARY ECTOTHRIXCHARACTER

This study supports the view that, in cases of tinea capitis due to a Microsporum canis infection, ectothrix arthroconidium formation is ext rapilary and arises from intrapilary hyphae. The hyphae of M. canis pe rforate and digest the hair cuticle to alter its appearance from a nor mally identifiable structure of imbricated cells with a distal free bo rder, to a grossly altered and pathological layer. Conidium production mainly takes place outside the hair shaft and forms thick clusters be tween the cuticular tiles. Finally, a shaft of conidia is formed aroun d the hair. The cuticular covering of such a conidium sheath belongs t o the root sheath of the hair follicle, and not to the hair structure proper.