A fungal parasite, such as certain dermatophytes, forming a sheath of spores on the outside of a hair as well as growing within the hair shaft.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Examples from the Web for ectothrix
Historical Examples of ectothrix
Of this latter there are two main subvarieties—endothrix and ectothrix.Essentials of Diseases of the Skin
Henry Weightman Stelwagon