What is cicatricial alopecia and how is it treated in a patient with a history of infected sebaceous cyst?

Cicatricial Alopecia: Definition and Treatment

Cicatricial (scarring) alopecia is a group of disorders characterized by permanent destruction of hair follicles replaced by fibrous scar tissue, requiring early aggressive anti-inflammatory treatment to prevent irreversible hair loss. 1

What is Cicatricial Alopecia?

Cicatricial alopecia represents approximately 5% of all hair loss consultations and differs fundamentally from non-scarring alopecias like alopecia areata because the hair follicle is permanently destroyed. 1

Primary cicatricial alopecias target the hair follicle as the main site of inflammation, classified by the predominant inflammatory cell type: 1, 2

• Lymphocytic group: Chronic discoid lupus erythematosus (DLE), lichen planopilaris, classic pseudopelade of Brocq, central centrifugal cicatricial alopecia 3
• Neutrophilic group: Folliculitis decalvans, dissecting cellulitis 3
• Mixed group: Folliculitis keloidalis 3

Secondary cicatricial alopecias occur when the follicle acts as an "innocent bystander" in diseases like scleroderma, dermatomyositis, or following severe infections like an infected sebaceous cyst. 1

Clinical Recognition

The hallmark clinical feature is loss of follicular ostia (pore openings) on examination—this distinguishes scarring from non-scarring alopecia. 4

Key diagnostic features include: 4, 2

• Patchy hair loss with smooth, shiny scalp surface lacking visible pore openings
• May present with erythema, scaling, pustules, or be completely asymptomatic in late stages
• Patients often report burning, itching, or tenderness (unlike alopecia areata which is typically asymptomatic)
• Disease onset is often subclinical and progresses slowly, making early diagnosis challenging 2

Dermoscopy is invaluable for identifying loss of follicular openings and distinguishing cicatricial from non-cicatricial causes. 4

Diagnostic Workup

Scalp biopsy is mandatory in all suspected cases of cicatricial alopecia to determine the type of inflammatory infiltrate and guide treatment. 3, 2

The biopsy should include: 1, 4

• Two 4mm punch biopsies from the active border of hair loss
• One specimen for vertical sectioning (standard histology)
• One specimen for horizontal sectioning (to assess follicular architecture)

Look for these histologic features: 3

• Dermal scarring with absent or reduced hair follicles
• Reduced number of erector pili muscles
• Type and location of inflammatory infiltrate (lymphocytic vs. neutrophilic vs. mixed)

Treatment Algorithm

Immediate Goals

The primary aim is to halt inflammatory progression and prevent further scarring—hair regrowth in already scarred areas will not occur. 2

First-Line Anti-Inflammatory Therapy

For most primary cicatricial alopecias, initiate combination topical and intralesional corticosteroid therapy: 2

• Topical corticosteroids: Class III-IV potency applied daily to affected areas 2
• Intralesional triamcinolone acetonide: 5-10 mg/mL injected into active areas of inflammation, repeated monthly 2

Systemic Therapy Based on Inflammatory Pattern

Lymphocytic cicatricial alopecias (DLE, lichen planopilaris): 2

• Hydroxychloroquine 200-400 mg daily for DLE
• Oral corticosteroids for acute flares
• Mycophenolate mofetil or methotrexate for refractory cases

Neutrophilic cicatricial alopecias (folliculitis decalvans): 2

• Long-term oral antibiotics (doxycycline 100 mg twice daily or rifampin combinations)
• Isotretinoin for severe cases

Mixed pattern: Combination antimicrobial and immunosuppressive therapy 2

Context: Infected Sebaceous Cyst

In a patient with history of infected sebaceous cyst, the cicatricial alopecia is likely secondary (follicle destruction from adjacent infection/inflammation rather than primary follicular targeting). 1

Treatment approach: 1

• Address any ongoing infection first
• Once infection cleared, the scarring is permanent—no treatment will restore hair in that area
• Focus on preventing expansion: topical corticosteroids to surrounding inflamed areas if present
• Surgical excision of residual cyst if still present to prevent recurrence

Critical Pitfalls

Early diagnosis is paramount—once scarring occurs, it is irreversible, making delayed diagnosis catastrophic for the patient. 5, 1

Do not confuse with alopecia areata: Unlike cicatricial alopecia, alopecia areata shows preserved follicular openings, exclamation mark hairs, and has potential for spontaneous regrowth (34-50% within one year). 6, 7

Biopsy is non-negotiable when diagnosis is uncertain—clinical presentation alone can be misleading, especially in early or late disease stages. 2

Psychological support is essential—permanent hair loss has profound impact on quality of life; offer counseling and camouflage techniques (wigs, scalp micropigmentation). 2