Trichostasis Spinulosa Clinical Presentation

Updated: Jan 31, 2017
  • Author: Nicholas V Nguyen, MD; Chief Editor: Dirk M Elston, MD  more...
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In most cases, the condition does not lead to any subjective complaint and is observed only as an incidental finding. Pruritus is occasionally present, as is roughness of the skin. Pruritus may be more common when lesions are present on the trunk and arms of young adults. In younger patients, the chief complaint may be a cosmetic concern about facial lesions, which are frequently confused with open comedones. In this setting, patients may report a history of unsuccessful treatment for acne.


Physical Examination

Pertinent physical findings of trichostasis spinulosa are limited to the skin. Because spinous plugs may be inapparent to the naked eye, examination of suspected lesions under a hand lens or with a dermatoscope is recommended.

Lesions typically appear as dark, follicular plugs or papules. The lesions may have protruding tufts or spines of fine hair that can easily be removed with a comedo extractor or small-toothed forceps without discomfort to the patient. The horny plugs are soft and contain 5-25 hairs per plug. Scales may sometimes be present. Note the image below.

Small, dark, follicular papules on the nose. Small, dark, follicular papules on the nose.

Lesions may occur anywhere on the body, but they characteristically appear on the face, especially the nose, and the upper part of the trunk and arms, especially the interscapular area. Lesions less typically appear on other areas of the head, neck, and cheeks.

Lesions are characteristically less than or equal to 1 mm.

Lesions characteristically are black.



The cause is unknown.

Various explanations for the hyperkeratosis and plugging of the follicular apparatus are proposed. Internal mechanisms, such as endocrine or metabolic disturbances, are suggested. Widespread trichostasis spinulosus has been reported with renal failure. [1] External mechanisms include the use of irritating soaps or paraffin-containing creams and prolonged exposure to dust, hydrocarbons, or industrial oils. Trichostasis spinulosa has also been associated with prolonged use of clobetasol. [2]

Some consider trichostasis spinulosa to be a variant of the comedonal lesions of acne; they note the similar distribution of lesions and the rarity of trichostasis spinulosa among preadolescent patients.

Microorganisms are also suggested to have a causative role. Propionibacterium acnes and Pityrosporum species are implicated as possible organisms.