trichostasis spinulosa trichostasis spinulosa trichostasis spinulosa is a common but rarely diagnosed disorder of the hair follicles that clinically gives the impression of blackheads, but the follicles are filled with funnel-shaped, horny plugs that are bundles of vellus hairs.: 768 not to be confused with trichodysplasia spinulosa. trichostasis spinulosaspecialtydermatology diagnosis standard skin surface biopsy (sssb) is a noninvasive method used for diagnosis. treatment