Lichen Planopilaris (LPP)
Lichen planopilaris (LPP) is the scalp-localized form of lichen planus and presents as a primary lymphocytic cicatricial alopecia. An autoimmune attack permanently destroys hair follicles, leaving irreversible patches of scarring hair loss, often with marked scalp pain and burning.
At its core, LPP results from a T-cell–mediated autoimmune reaction combined with disordered lipid metabolism in the hair follicle:
- Loss of immune privilege and attack on stem cells: Autoreactive CD8+ T lymphocytes are activated and mistakenly target self-antigens in the follicular basement membrane. They gather and heavily attack the bulge region, home to the follicular stem cells. Once the bulge is destroyed, the follicle can no longer regenerate in later anagen cycles.
- Reduced PPAR-gamma (peroxisome proliferator-activated receptor gamma): A major advance in understanding LPP. Lower expression of this nuclear receptor disrupts normal lipid metabolism in the sebaceous gland and follicle. The resulting build-up of toxic proinflammatory lipids sets off self-perpetuating inflammation and drives fibrosis of the dermis around the follicle.
- JAK-STAT and IFN-gamma signaling: Infiltrating T cells release large amounts of interferon-gamma (IFN-gamma), activating the JAK1/JAK2 pathway in follicular epithelial cells. This keeps inflammation going, pushes follicle cells into apoptosis and replaces the follicle with dense collagen scar tissue.
At Haute-Derma, we treat LPP as an urgent hair-preservation task. Diagnosing it early, before scarring sets in, lets us shut down the autoimmune inflammation and protect follicular stem cells that have not yet been permanently destroyed.
Clinical Features and Differential Diagnosis
Lichen planopilaris has several warning features that a dermatologist should note from the very first visit:
- Prominent scalp symptoms (trichodynia): Patients often describe burning, stinging, intense itching or a deep burning pain in the scalp that gets worse when the hair is touched or when wind blows on it.
- Progressive patches of scarring hair loss:
- Patches are slightly atrophic, smooth and shiny, with complete loss of follicular openings.
- Perifollicular casts / scaling: At the active edge of a patch, grayish-white tubular scale wraps tightly around the base of the remaining hairs.
- Perifollicular erythema / violaceous halo: The skin around hair roots at the advancing edge is red with a purple rim, reflecting an active lymphocytic infiltrate.
- Trichoscopy findings:
- Adherent collars of scale around the follicle openings (perifollicular casts).
- Linear or dotted dilated vessels around the follicle openings.
- White dots or milky-white fibrotic areas where follicles have been completely replaced by scar tissue.
- Differential diagnosis:
- Discoid lupus erythematosus (DLE): DLE usually shows adherent "carpet tack" scale, more pronounced atrophy, marked pigment changes and a band of immune deposits at the basement membrane (positive DIF).
- Androgenetic alopecia (AGA): AGA has no perifollicular scale, no burning pain, and follicular openings are preserved.
How Haute-Derma Diagnoses and Treats LPP
- Imaging and biopsy: Trichoscopy pinpoints the edge of the patch with the most active inflammation. A 4 mm scalp punch biopsy is then taken, including the whole follicle down to the subcutaneous fat:
- Histopathology: A band-like lymphocytic infiltrate around the upper follicle (infundibulum and isthmus), with vacuolar degeneration of the basal layer and perifollicular fibrosis.
- Intensive anti-inflammatory medical treatment:
- Topical and intralesional corticosteroids (ILTAC): Triamcinolone acetonide is injected directly into the edge of the patch to quickly quell the T-cell infiltrate, combined with clobetasol propionate foam or gel applied at home.
- Hydroxychloroquine (HCQ): The leading oral immunomodulator, which reduces antigen presentation and dampens chronic autoimmune inflammation.
- Doxycycline (anti-inflammatory dose, 50–100 mg/day): Through its anti-inflammatory and matrix metalloproteinase (MMP)–inhibiting effects, doxycycline effectively eases scalp burning and pain.
- PPAR-gamma agonist (pioglitazone): Oral pioglitazone (15–30 mg/day) is used to restore PPAR-gamma function, normalize follicular lipid metabolism and halt fibrosis.
- JAK inhibitors (tofacitinib / baricitinib): A modern targeted option for rapidly progressive LPP that has not responded to conventional treatment.
- Supportive therapy and gentle scalp care:
- Low-level laser therapy (LLLT) to support repair of the surrounding dermis.
- Guidance on gentle hair washing with lukewarm water, and strict avoidance of harsh mechanical friction (scratching, rubbing) and perming or coloring chemicals that can trigger flares.
Clinical Variants of Lichen Planopilaris
| Variant | Typical Clinical Features | Associated Findings |
|---|---|---|
| Classic LPP | Scattered patches of scarring alopecia on the crown or temples; prominent perifollicular scale and redness. | May occur with lichen planus of the skin, nails or oral mucosa. |
| Frontal fibrosing alopecia (FFA) | Band-like recession of the frontotemporal hairline; smooth, shiny, slightly atrophic forehead skin. | Complete eyebrow loss (75–80% of cases); small skin-colored facial papules. |
| Graham-Little-Piccardi-Lassueur syndrome (GLPLS) | A rare triad: scarring alopecia of the scalp + non-scarring hair loss in the armpits/groin + follicular lichenoid papules on the body. | Mostly affects middle-aged women; runs a persistent course. |
