Trichostasis spinulosa: An overlooked entity.

A 50-year-old female visited our department for the treatment of rosacea. Dermatological examination revealed erythematous papules and plaques over both cheeks. Black macules were found on the nose [Figure 1], but the patient was not worried about the lesions. Dermoscopic (×25 and ×60) examination revealed that the black macules were vellus hairs [Figure 2]. The hairs were plucked and observed under dermascope which showed multiple vellus hairs bundled in a funnel-like structure [Figure 3]. The above findings were suggestive of trichostasis spinulosa (TS). Patient refused treatment for the lesions.

Figure 1

Multiple black macules on nose

Figure 2

Dermoscopic (×25 and ×60) examination revealing vellus hairs

Figure 3

Plucked hairs observed under dermascope (×25 and ×60) showing multiple vellus hairs bundled in a funnel-like structure

TS is a very common but unrecognized disorder of pilosebaceous unit. It is a midfacial disease that occurs in younger age in female patients with Fitzpatrick skin type III or higher. It may also occur in light-skinned older people with excessive ultraviolet-exposure.[12]

TS was first recognized by the German dermatologist Felix Franke in 1901, who named it “Pinselhaar” (paintbrush hair). In 1913, Noble first coined the term “trichostasis spinulosa.”[1] The exact etiology of this disease is not known. Abnormal angulation of the hair follicle may lead to the entrapment of vellus hairs. Follicular hyperkeratosis of a dilated vellus hair follicle leading to retention of successive telogen hairs is another explanation. Number of retained hairs may range from 5 to 60.[12]

TS occurs sporadically, but many trigger factors have been identified. These include topical minoxidal, topical steroids, chronic renal failure, dust, oils, ultraviolet light, heat, and irritants.[12]

Two variants of TS have been described: Nonpruritic type, which is classical and often seen in the elderly as asymptomatic blackhead-like lesions located on the face. The other variant is the pruritic type, characterized by multiple pinhead-sized papules on the trunk and upper extremities in young adults.[3] The present case is a classical type with the involvement of nose.

Various modalities of treatment are tried with variable results which includes emollients, hydroactive adhesive tapes, local keratolytics, local and oral retinoids.[1] Repeated peeling with capryloyl salicylic acid has given good result.[2]

Herein we present a classical case of TS to increase the awareness of this common disease.