"Black dot" ringworm is caused by

Tinea capitis can be either ectothrix or endothrix type of infection. hair can be infected with Trichophyton and Microsporum fugai. Ectothrix are usually inflammatory and caused by microsporum and endothrix are usually non inflammatory and caused by trichophyton. Tinea capitis is classified into Non inflammatory and inflammatory types. Non Inflammatory: Black dot Grey patch Inflammatory Kerion Favus So black dot is non inflammatory endothrix type of infection caused by trichophyton Ref Harrison 20th edition pg 1324