Trichostasis Spinulosa

Trichostasis spinulosa is a common, benign disorder of hair follicles in which keratin plugs contain a bundle of retained vellus hairs, giving a dark, comedone like appearance.

It occurs mainly in adults over 40 years, though it can start in adolescence, and is slightly commoner in women. Sites are the nose, cheeks, forehead, chin, upper back and chest, and also the extremities in some.

It is often unrecognised and mistaken for blackheads. The condition is harmless and persistent.

Pathophysiology.

Retention of old vellus hairs in an abnormal follicle, with failure of the hairs to be shed because of follicular keratinisation. The hairs accumulate in the follicle, and the plug forms a visible dark point.

Sun damage, topical agents (such as corticosteroids) and obstruction of the follicle are associated factors.

• Small, asymptomatic, dark brown to black spiny or comedone like follicular papules, 1 to 3 mm, often on the nose and cheeks.
• A tuft of hairs protruding from the follicle, which may be itchy or give a rough texture.

• Clinical diagnosis. Dermoscopy shows a tuft of vellus hairs inside a keratin plug. Squeezing the lesion produces a tuft of hairs (not sebum).
• Biopsy is rarely needed: a dilated follicle with keratin and many vellus hairs.

Differential diagnosis.

• Open comedones (blackheads), keratosis pilaris and Favre-Racouchot syndrome.
• Pityrosporum folliculitis, sebaceous filaments and follicular lichen planus.
• Pilar cysts and syringoma.

• Reassure the patient that the condition is harmless. Treatment is for appearance and symptoms.
• Topical tretinoin 0.025 to 0.05% nightly, adapalene 0.1% or salicylic acid 2% to 6%, for several months. Urea 10 to 20% cream.
• Adhesive strips and waxing remove the hairs temporarily. Laser hair removal (diode or alexandrite) offers longer clearance in some patients.
• Oral isotretinoin has been used in resistant disease (low dose, avoiding pregnancy).
• Recurrence is common after stopping treatment.

Special groups. Women who may become pregnant: avoid topical tretinoin and isotretinoin in pregnancy.

Monitoring. Review after 3 months of treatment.

Referral and escalation. Dermatology for resistant disease.