Sebaceous filaments: An exaggerated manifestation of normal skin physiology

A 30-year-old male with a history of acne and seborrheic dermatitis presented with persistent whitish specks on the dorsum of the nose, along with creamy-white, thread-like structures along the nasal creases for 2 years, which he periodically expressed manually. Examination revealed whitish follicular outgrowths in both nasal creases [Figure 1a and b]. Dermoscopy showed elongated white excrescences around hair follicles [Figure 1c].

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Figure 1:

(a) Tiny white specks on the nasal tip and dorsum, with creamy-white thread-like structures along the right alar groove. (b) Creamy-white thread-like structures along the left alar groove. (c) Dermoscopy shows discrete, cylindrical, homogeneous white excrescences adjacent to vellus hair follicles (Dermlite DL4N; ×10, polarized mode).

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Sebaceous filaments are asymptomatic, whitish, cylindrical accumulations of sebum, bacteria, and corneocytes around hair follicles, commonly found in sebum-rich areas such as the nose and alae nasi, particularly in genetically predisposed, post-pubertal individuals with seborrhea, enlarged pilosebaceous pores, and poor hygiene.^[1] They represent a physiological variation of sebaceous follicles; in the lower infundibulum, the unusually thin, non-laminated granular layer is shed, producing a loose, porous keratinous core that facilitates sebum outflow to the surface.^[2]

Treatment involves short-contact topical retinoids for mild cases, curettage for small filaments, and oral retinoids for larger ones to reduce gland activity and sebum.^[1]