Scarring alopecia red flags

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Scarring alopecia is a clinicopathological outcome in which inflammation destroys the follicular unit and permanent fibrous tissue replaces it. Primary forms target follicles; secondary scarring follows burns, radiotherapy, tumour, severe infection or trauma. The practical recognition rule is disappearance of follicular openings in an area of hair loss, supported by shiny surface change, perifollicular inflammation or tufting. Early active disease may have subtle density loss but prominent itch, tenderness or burning.

Patterns guide but do not prove cause. Lichen planopilaris produces irregular patches with scale cuffing individual hairs; frontal fibrosing alopecia creates a band of recession and eyebrow loss; central centrifugal cicatricial alopecia expands from the crown; discoid lupus may leave dyspigmented atrophic plaques; folliculitis decalvans adds pustules and polytrichia. These appearances must be assessed in every skin tone. Erythema may appear red, violaceous, grey or dark brown, while scale and loss of ostia remain visible with magnification.

Time matters because the aim is to stop activity around follicles that remain. High-quality history, dermoscopy, microbial sampling where indicated and a correctly sited biopsy allow diagnosis; empirically rotating antifungals, oils and corticosteroids obscures activity. Hair-care advice should be collaborative: remove harmful tension or chemicals when the timeline supports them, without blaming culturally important practices or assuming they explain an inflammatory disease.

Key points

Primary cicatricial alopecia destroys follicular stem-cell regions and replaces follicles with fibrosis; treatment can preserve remaining hair but cannot reliably regenerate established scar.
Look for absent follicular openings, shiny atrophy, perifollicular scale or erythema, pustules, crust, tufting and symptoms of pain, burning or itch.
Lichen planopilaris often shows perifollicular scale and erythema; frontal fibrosing alopecia recedes the frontotemporal hairline and commonly reduces eyebrows.
Central centrifugal cicatricial alopecia typically begins at the vertex and expands centrifugally, especially in women of African ancestry, but it is not caused by ethnicity and hair practice is only one possible modifier.
Traction loss begins in sites under repeated tension and can be reversible early; longstanding tension produces permanent scar, so ask neutrally about styles, adhesives, chemicals, heat and pain.
Pustules, crust and tufted multiple hairs suggest folliculitis decalvans or another infective-neutrophilic process and require bacterial sampling plus urgent specialist assessment.
Trichoscopy and consented photographs map active margins. If biopsy is needed, sample an inflamed edge with remaining follicles rather than a smooth burned-out centre.
Biopsy planning should specify site, orientation and clinical differential to dermatopathology and include bleeding, infection, scar and local permanent hair loss in consent.
Do not wait for widespread baldness before referral: symptoms and inflammatory signs may precede obvious density loss.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Lymphocytic follicular inflammation

Lichen planopilaris, frontal fibrosing alopecia, CCCA and discoid lupus direct immune injury toward follicular structures that sustain regrowth.

Neutrophilic follicular inflammation

Folliculitis decalvans and dissecting disease combine pustulation, microbial interactions and destructive inflammation, often producing tufted hairs and crust.

Secondary physical destruction

Longstanding traction, burns, radiation, severe infection, tumour and trauma can destroy follicles even when they were not the original immune target.

Multifactorial susceptibility

Genetic background, mechanical stress and product exposure may modify selected conditions, but no single practice or ancestry explains every case.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Stem-cell niche is injured
Inflammation attacks the bulge region that contains epithelial stem cells, removing the follicle's capacity to regenerate a cycling hair shaft.
2
Follicles are replaced
Destroyed units collapse and are replaced by fibrous tissue, causing smooth skin and permanent disappearance of follicular openings.
3
Activity advances at margins
Inflammatory disease often spreads around remaining peripheral hairs, leaving a quieter scarred centre and a diagnostically valuable active edge.
4
Infection amplifies destruction
Fungal invasion or pustular bacterial-neutrophilic inflammation can rapidly damage follicles, making organism-directed treatment and inflammatory control time sensitive.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Missing follicular openings

Smooth shiny skin without regular ostia in an alopecic area is the central sign that follicles have been replaced by scar.

Perifollicular activity

Scale collars, erythema, hyperkeratosis, itch, pain or burning around remaining edge hairs identify a useful active zone for urgent assessment.

Frontotemporal recession

A pale scarred band behind the former hairline with isolated lonely hairs and eyebrow reduction supports frontal fibrosing alopecia.

Central centrifugal expansion

Reduced density and loss of ostia beginning at the vertex and spreading outward, sometimes with tenderness or breakage, suggests CCCA.

Pustules and tuftingRed flag

Crust, pustules and several shafts emerging from one enlarged opening suggest folliculitis decalvans or another neutrophilic destructive process.

Traction distribution

Broken hairs and marginal loss at sites of sustained pull may retain a fringe early; shiny skin later indicates irreversible traction scar.

Red flags requiring action

Loss of follicular openings, perifollicular erythema or scale, scalp pain or burning, pustules, tufted hairs, shiny atrophy, a rapidly receding frontotemporal line or central crown expansion warrants expedited dermatology assessment because lost follicles cannot regrow.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Whole-scalp examination and trichoscopyFirst step
Why
Map pattern, identify retained ostia and locate active inflammatory margins.
Interpretation and limitations
Loss of openings confirms destructive change clinically; perifollicular scale, casts, pustules, tufting and vessel or pigment patterns help select biopsy rather than replace histology.
02
Standardised clinical photography
Why
Measure recession, centrifugal spread and inflammatory activity over time.
Interpretation and limitations
Use consistent lighting, parting, hair preparation and landmarks with consent; hairstyle changes can mimic density change if technique is not reproducible.
03
Fungal microscopy and culture
Why
Exclude inflammatory tinea where scale, broken hairs, nodes or a boggy plaque is present.
Interpretation and limitations
Sample affected hairs and scale; a severe kerion requires systemic treatment before culture returns because delayed therapy can itself cause scar.
04
Bacterial swab and culture
Why
Identify treatable organisms in pustular, crusted or draining follicular disease.
Interpretation and limitations
Take material from an active pustule before antibiotics when safe, but interpret colonisation with morphology and response rather than treating every positive swab alone.
05
Active-edge scalp biopsy
Why
Distinguish lymphocytic, neutrophilic and mixed cicatricial alopecia and guide treatment.
Interpretation and limitations
Dermatology commonly selects one or two 4 mm punches from inflamed hair-bearing margin for vertical and transverse assessment according to local pathology protocol; a bare centre is low yield.
06
Targeted systemic tests
Why
Assess lupus, endocrine, nutritional or medicine-related contributors when the phenotype supports them.
Interpretation and limitations
Select blood count, ferritin, thyroid or autoimmune tests from clinical evidence; a positive antinuclear antibody alone does not diagnose discoid lupus of the scalp.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Alopecia areata

Smooth patches retain follicular openings and may show exclamation-mark hairs or nail pitting without the perifollicular scale of active scar.

Androgenetic alopecia

Patterned density loss shows miniaturised variable-calibre hairs but preserves ostia and lacks pain, pustules and shiny replacement fibrosis.

Tinea capitis

Scale, broken hairs, nodes and boggy inflammation require mycology; severe kerion can become a secondary scarring cause rather than a benign mimic.

Trichotillomania

Irregular patches with shafts broken at multiple lengths and no primary loss of openings suggest repeated manipulation, though chronic trauma can complicate appearance.

Cutaneous tumour

A firm, ulcerated, bleeding or rapidly enlarging scalp lesion with alopecia needs urgent biopsy to exclude infiltrative primary or metastatic disease.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Recognise activityRefer while follicles remainFirst stepMissing openings or perifollicular inflammation suggests an active scarring alopecia.

1Document symptoms, tempo, distribution, medicines and hair practices, then examine the entire scalp, brows, facial hair, skin, nails and mucosa for diagnostic clues.
2Take standardised photographs and use trichoscopy to mark an active margin; obtain fungal or bacterial samples when scale, pustules or exposure supports infection.
3Arrange expedited dermatology referral, stating pain, pustules, eyebrow loss, rate of recession and any systemic red flag rather than labelling the referral as nonspecific hair loss.

02BiopsySample the active process safelyClinical pattern remains uncertain or histology will determine anti-inflammatory treatment.

1Agree the biopsy site with dermatology or dermatopathology, choosing an inflamed edge that retains follicles and avoiding a completely smooth scarred centre.
2Explain local anaesthetic, bleeding, infection, sutures, permanent small scar and focal permanent hair loss, and obtain explicit consent for clinical photography and pathology use.
3Label exact scalp site and orientation, provide differential and treatment history, and arrange ownership of histology, wound review and suture removal before the procedure.

03Reduce modifiersProtect remaining follicles without blameTension, adhesive, heat, chemical injury or scratching may be worsening an inflammatory or traction process.

1Ask which practices matter to the person and identify pain, tightness, breakage or temporal links rather than issuing a culturally insensitive blanket prohibition.
2Agree lower-tension alternatives, pauses in adhesive or chemical use and gentle scalp care while specialist diagnosis proceeds.
3Treat confirmed inflammatory disease independently, because changing hair practice alone does not suppress lichen planopilaris, CCCA or folliculitis decalvans.

04Acute pustular diseaseControl infection and destruction promptlyPainful pustules, boggy swelling, crust, spreading erythema or systemic illness is present.

1Assess observations, immune status and extent and arrange same-day acute care for fever, sepsis, extensive cellulitis or a vulnerable host.
2Collect fungal hair and scale or bacterial pus samples as indicated, then start the appropriate systemic pathway without relying on topical therapy alone for kerion or deep disease.
3Secure urgent dermatology follow-up to confirm organism, distinguish neutrophilic cicatricial disease and document whether follicles remain after inflammation settles.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Permanent hair loss

Fibrosis prevents regrowth from destroyed follicles, so delayed inflammatory control leaves an expanding and irreversible visible hair deficit.

Secondary infection

Pustules, erosions and treatment immunosuppression create bacterial or fungal complications that can accelerate pain and tissue damage.

Treatment toxicity

Long courses of potent topical, injected or systemic immune treatment can cause skin, infection, metabolic, organ and reproductive adverse effects.

Psychosocial and cultural harm

Visible permanent loss, insensitive advice and loss of valued styling options can affect identity, confidence, relationships and engagement with care.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Compare fixed-landmark photographs and trichoscopic inflammatory signs at intervals set by activity, not only the size of established bald scar.
Ask whether itch, pain, burning, pustules or shedding is improving; symptoms can reveal activity before photographs show recession.
Track bacterial or fungal culture results to a named clinician and revise treatment from organism and diagnosis rather than leaving empirical courses repeated.
After biopsy, document histological clinic correlation, wound healing and the treatment decision the procedure was intended to answer.
Monitor disease-specific systemic or potent topical treatment through dermatology, including infection, blood, liver, renal, eye and reproductive safeguards as applicable.
Continue psychosocial, wig and camouflage support after inflammation stops because established scar and visible difference may remain permanent.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Symptoms can lead signs

Burning, tenderness or itch may precede obvious density loss, offering a window to diagnose and suppress inflammation before widespread destruction.

The centre records history

A smooth bald centre proves previous destruction but contains little active inflammation; its margin is usually more useful for diagnostic biopsy.

Erythema changes colour

Active inflammation can appear violaceous, grey or dark brown in richly pigmented skin, so perifollicular scale and symptoms prevent under-recognition.

Hair practice is not identity

Tension and chemicals may modify risk, but ancestry or a culturally important style is not itself a diagnosis or sufficient explanation.

Stabilisation is success

Because scarred follicles cannot regrow, preserved remaining density and resolution of symptoms are meaningful outcomes even without filling bald areas.

11Common pitfallsFrequent interpretation and management errors.

01
Waiting for a large shiny bald area before referring painful perifollicular inflammation.
02
Taking a biopsy from the featureless scarred centre rather than an active hair-bearing margin.
03
Calling every central loss in a Black woman traction and overlooking CCCA.
04
Giving repeated topical antifungals for pustular destructive disease without adequate hair or pus sampling.
05
Assuming normal red colour excludes inflammation in deeply pigmented skin.
06
Promising regrowth from an area in which follicular openings have already disappeared.