Trichostasis spinulosa

What is trichostasis spinulosa?

Trichostasis spinulosa (TS) is a common yet underdiagnosed benign follicular disorder mainly affecting adults. It is commonly seen on the nose, face, and cheek but can affect other body parts.

TS appears as multiple entrapped vellus hairs in a hyperkeratotic dilated hair follicle (tiny open pores with numerous tiny hairs) which can be mistaken for acne. A follicle can retain 5-60 hairs and it is usually 1mm in size, usually only visible with a magnifying glass.

TS on the nose - multiple hairs emanate from each follicle 

A close up of TS on the nose (TS-patient1)

Comedo-like lesions due to nasal TS 

See more images of trichostasis spinulosa

Who gets trichostasis spinulosa?

• TS is common in adults, especially older adults.
• Rarely affects children.
• Equally affects males and females, however female patients with Fitzpatrick skin type III or more may be more commonly affected.

What causes trichostasis spinulosa?

The exact cause is unknown. However, several aetiologies have been proposed.

• Sporadic
• Internal and external triggers
  • Internal: medical causes (endocrine and renal failure)
  • External: irritants (eg, soaps), medications (eg, long-term topical steroids), dust, oils, ultraviolet light, and heat

What are the clinical features of trichostasis spinulosa?

• Often asymptomatic

• Younger patients may present with cosmetic concerns of ‘unsuccessful’ acne treatment

• Cutaneous features

  • Black, comedo-like dots in 2 main variants
    • Non-pruritic (classical): solitary lesion, typically on the face of elderly individuals
    • Pruritic: multiple lesions, usually on the trunks and limbs of young adults

• Skin may be rough and scaly

• Erythema and oedema around manipulated lesions

• Non-cutaneous features

  • Hair breakage or non-scarring alopecia eg, eyebrows

How do clinical features vary in differing types of skin?

The dark comedo-like lesions may be less evident in darker skin types.

What are the complications of trichostasis spinulosa?

• Pruritus with risk of bacterial skin infection from scratching
• Hair loss eg, eyebrows and eyelashes
• Facial disfigurement
• Psychological distress and loss of confidence

How is trichostasis spinulosa diagnosed?

• History and physical examination
• Microscopic examination

A bundle of multiple vellus hairs surrounded by a keratinous sheath can be seen after potassium hydroxide solution application. The hair bundle can be removed for examination using either forceps or a comedone extractor.

Microscopy of TS - multiple vellus hair arising from a single follicle 

• Dermoscopic examination

  • Quick, inexpensive, and accurate way to diagnose TS
  • Multiple tiny, pigmented hairs coming out of the same dilated pore
  • The hairs are usually vellus hairs (short and fine)
  • A pore/follicle can retain 5-60 hairs and it is usually 1mm in size

• Skin biopsy

  • Usually not required
  • Performed when there is an inconclusive diagnosis
  • Provides definitive diagnosis featuring enlarged hair follicles with trapped small hairs and keratin

What is the differential diagnosis for trichostasis spinulosa?

• Comedonal acne: Also known as blackheads and can resemble the dark plugs seen in TS.
• Keratosis pilaris: Characterised by rough patches and small, acne-like bumps, usually on the arms, thighs, cheeks, and buttocks.
• Favre-Racouchot syndrome: Characterised by the combination of multiple open comedones and nodular elastosis due to sun exposure.
• Phrynoderma: Also known as toad skin, this condition is characterised by follicular hyperkeratosis, usually associated with vitamin A deficiency.

What is the treatment for trichostasis spinulosa?

No treatment is necessary. However, removal may be sought for cosmetic reasons.

No specific treatment has been widely accepted.

General measures

• Good skin care routine (cleansing, exfoliation and moisturising)

Specific measures

• Topical
  • Exfoliation
  • Use of forceps or a comedone extractor to remove the plugs
  • Keratolytics e.g lactic acid, urea, salicylic acid
  • Depilatory wax or adhesive strips
  • Retinoids (eg, adapalene and tretinoin): preventative, used after extracted lesions
• Chemical peels
  • Capryloyl salicylic acid peelings
• Laser therapy
  • 755-nm long-pulsed alexandrite laser has been used in some studies (800-nm in skin phototypes III-IV).
• Professional extraction
  • Needle or tweezer evacuation
  • Hydroactive adhesive tape stripping

How do you prevent trichostasis spinulosa?

TS often goes undetected and does not require any specific prevention.

The exact causes and risk factors of TS are still unknown, therefore there are no established ways to prevent it. It is important to educate patients on the condition and encourage good skin and hair care.

What is the outcome for trichostasis spinulosa?

The prognosis of TS is generally favourable, and the condition is harmless. However, it is important to note that it may negatively impact self-esteem and cause emotional distress. Hence, effective management strategies and regular follow-up should be considered.

Some cases may resolve spontaneously. Following treatment, the condition may reappear upon discontinuation of the specific treatment.