Scarring Alopecias - Follicle Fallout
- Irreversible hair loss due to destruction of hair follicle stem cells & replacement by fibrous tissue.
- Also known as cicatricial alopecias.
- Classification based on predominant inflammatory infiltrate:
- Lymphocytic
- Lichen Planopilaris (LPP)
- Frontal Fibrosing Alopecia (FFA)
- Chronic Cutaneous Lupus Erythematosus (CCLE) / Discoid Lupus Erythematosus (DLE)
- Central Centrifugal Cicatricial Alopecia (CCCA)
- Neutrophilic
- Folliculitis Decalvans
- Dissecting Cellulitis (Perifolliculitis Capitis Abscedens et Suffodiens)
- Mixed
- Acne Keloidalis Nuchae
- Lymphocytic
⭐ Scarring alopecias involve destruction of hair follicle stem cells, leading to irreversible hair loss and permanent scarring of the affected scalp areas, distinguishing them from non-scarring forms where the follicle remains intact and regrowth is possible.
Lymphocytic Types - Immune Invasion
- Mechanism: Lymphocytic inflammation targets hair follicles, leading to permanent destruction and scarring.
- Key Types Compared:
| Feature | Lichen Planopilaris (LPP) | Frontal Fibrosing Alopecia (FFA) | Discoid Lupus Erythematosus (DLE) - Scalp |
|---|---|---|---|
| Target | Middle-aged women | Postmenopausal women | Women > Men (20-40 yrs) |
| Clinical | Perifollicular erythema/scaling, pruritus; patchy loss. | Symmetric frontotemporal recession, eyebrow loss. | Erythematous plaques, adherent scale, follicular plugs, atrophy. |
| Sites | Vertex, parietal scalp. | Frontal hairline, eyebrows. | Sun-exposed scalp, ears. |
| Histo | Lymphocytic infiltrate (bulge), perifollicular fibrosis. | LPP-like, often paucicellular. | Interface dermatitis, follicular plugging, ↑mucin. |
| Assoc. | Oral/cutaneous LP. | Often none. | SLE (~5-10%). |
| ⭐ Highlight | > Perifollicular erythema & scaling. | > "Lonely hair" sign; band-like recession. | > "Carpet tack" sign; dyspigmentation. |
Neutrophilic & Mixed Types - Pustule Problems
- Primarily neutrophilic (Folliculitis Decalvans, Dissecting Cellulitis) or mixed (CCCA with pustules).
- Features: Follicular pustules, inflammation leading to irreversible follicle destruction and scarring alopecia.
- Symptoms: Pain, pruritus, tenderness, purulent discharge are common.
| Feature | Folliculitis Decalvans (FD) | Dissecting Cellulitis (DSC/PCAS) | Central Centrifugal Cicatricial Alopecia (CCCA) |
|---|---|---|---|
| Key Clinical | Chronic pustules, erosions, crusts; Tufted hairs | Painful, boggy nodules; Interconnecting sinus tracts; Discharge | Progressive central scarring; Pruritus, breakage; ±Pustules |
| Primary Cells | Neutrophils (dominant) | Neutrophils (early), then Mixed inflammation | Lymphocytes (predominant); Neutrophils if 2° infection |
| Common Site | Vertex, occiput | Vertex, occiput; can be diffuse | Crown, vertex; spreads centrifugally |
| Assoc. (📌) | - | 📌 Follicular Occlusion Tetrad (acne conglobata, HS) | Common in women of African descent; Familial link |
| Rx Highlights | Systemic antibiotics (Clinda+Rifa), Oral Isotretinoin | Oral Isotretinoin (1st line), Antibiotics, TNF-α inhibitors | Potent topical/IL steroids, Tetracyclines (anti-inflam.) |
⭐ Tufted hairs (multiple hairs from one follicle) are characteristic of Folliculitis Decalvans.
Diagnosis & Management - Scalp Savers
- Diagnosis:
- History (itch, pain), exam (erythema, scaling, ↓follicular openings).
- Trichoscopy: Essential. Shows perifollicular scaling/erythema, absent ostia, tufting.
- Scalp Biopsy: Gold standard. 4mm punch from active edge; horizontal & vertical sections.
⭐ Scalp biopsy with both horizontal and vertical sections is crucial for accurate diagnosis of scarring alopecias.
- Management:
- Goal: Arrest progression, control inflammation, relieve symptoms.
- Early, aggressive therapy vital.
- Medical: Potent topical/intralesional corticosteroids. Systemic: Hydroxychloroquine, methotrexate, cyclosporine. Antibiotics for neutrophilic types.
- Surgical: Hair transplant if stable for >1-2 years.
- Diagnostic Algorithm:
High‑Yield Points - ⚡ Biggest Takeaways
- Scarring alopecias cause irreversible hair loss due to follicular destruction and fibrosis.
- Lichen Planopilaris (LPP) presents with perifollicular erythema and scaling; Frontal Fibrosing Alopecia (FFA) is a key variant.
- Discoid Lupus Erythematosus (DLE) on the scalp shows erythematous plaques, follicular plugging, and atrophic scarring.
- Central Centrifugal Cicatricial Alopecia (CCCA) typically affects Black women, starting at the vertex/crown.
- Folliculitis Decalvans is characterized by chronic neutrophilic inflammation, pustules, and tufted hairs.
- Dissecting cellulitis of the scalp involves deep, interconnecting abscesses and sinus tracts.
- Scalp biopsy is crucial for diagnosis, often revealing loss of sebaceous glands and specific inflammatory patterns.
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