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Clinical approach to diagnosing scarring alopecia
In case of human beings, the scalp hair is as much a protective
covering for the head as an important aspect of a persona. Scalp
hair loss (especially if it happens to be irreversible hair loss)
has always been considered a great loss – a loss that mars
personality and may cause mental anguish. Quite naturally, hair
problems have always been, and will remain to be, a grave matter
of discussion. The ensuing article focuses on the different forms
of primary cicatricial alopecias and on the clinical approaches
to diagnose the conditions well in advance.
Scarring alopecia by definintion involves scarring of the hair
follicles in the skin and ultimately the destruction of the hair
follicle itself. The main difference between primary and secondary
scarring alopecias is that in the case of primary cicatricial alopecias
some disorders or pathogenetic mechanisms target and damages the
hair follicle specifically, whereas in the case of secondary cicatricial
alopecia conditions, the damage caused to body organs and tissues
stimulates or induces alopecia as part of the larger condition.
Diagnosing primary cicatricial alopecia conditions is essentially
a challenging job, and this is attributable to a variety of reasons.
Many alopecic conditions are initially non-scarring and hence go
unnoticed. Some primary scarring alopecias follow a sluggish developmental
pattern – with phases of dormancy in between two active phases – deferring
the diagnosis. Some diagnoses among the alopecic conditions are
yet to be fully understood – their etiology (the science of
the causes and/or origins of the disease), clinical manifestation
as well as pathologic features have not been clearly distinguished.
To top it all, from what we do know at this stage in our understanding,
the heterogenous group of primary scarring alopecias present overlapping
clinical and histopathologic (the microscopic changes brought about
in the tissues by the disorder) features, further complicating the
diagnostic dilemma. So if your dermatolgogist is having difficulty
diagnosing a scarring alopecia and explaining the problem to you – please
understand that the situation is not his or her fault, but that
the condition itself is complex and makes diagnosis challenging.
Clinical
approach to scarring alopecias diagnosis
Diagnosis involves ‘the act or process of discovering or
identifying a disease condition by means of a medical examination,
laboratory test, etc.’. The clinical approach to diagnose
patients with cicatricial alopecias typically includes Scalp Examination
and then Scalp Biopsy. Scalp examination involves examining or inspecting
the scalp for possible signs of scarring alopecia disorders.
The inspection is undertaken with the help of a three-fold or a
greater magnifying lens or a dermatoscope (a more sophisticated
magnifying instrument). This helps locate the areas of active disease.
The first thing which needs to be clearly stated in this regard
is that cicatricial alopecias (scarring alopecias) – both
primary and secondary – are typically marked by the loss of
follicular ostia. Follicular ostia are the openings of the hair
follicles through which the hair fibers emerge from the skin. This
is the single most visible factor that identifies a scarring alopecia.
The comparison between the scarred and affected areas and the normal
hair-bearing areas at the same, times gives an inkling of the pathologic
condition. The appearance of follicular and interfollicular stigmata
(any sign characteristic of a specific disease) like erythema, hyperkeratosis,
pigmentary alteration and/or atrophy, the pattern of alopecia (patchy,
reticulate, central, etc.) as well as the presence of extra-cranial
cutaneous and systemic features helps evaluate the exact alopecia
condition.
All the same, scalp examination is merely the prelude to scalp
biopsy. Scalp biopsy entails the essential medical examinations
carried out to confirm the diagnostic impressions formed by scalp
examination. The sampling for scalp biopsy is performed from sites
that have clinically active disease and have tested positive for
the hair pull test.
The pull test is all about quantifying or determining the number
of hair follicles that have reached the telogen state or the so-called
resting state. The pull test involves taking a few strands between
the thumb and the forefinger and pulling them gently. The anagen
or the growing hair strands remain rooted but the hair follicles
that have reached telogen phase come out. The pull test particularly
helps in diagnosing scarring alopecias as a good indicator of the
existence of active lichen planopilaris and occasionally of chronic
cutaneous lupus erythematosus.
Sampling from end-stage or already bald areas of scarring alopecias
will not yield any significant pathologic information. In scarring
disorders with minimal or negligible outward manifestations, as
in pseudopelade of Brocq, the inflammation is hardly discernable.
In such cases, biopsy of a hair-bearing site with relative scantiness
of hair growth (or relative paucity of follicular ostia, but not
a complete absence of ostia) is recommended.
Different tests have been part of scalp biopsy procedures undertaken
by the different groups of researchers engaged in diagnosing and
classifying the various forms of scarring alopecias. The following
tests, however, are considered standard in determining or correctly
identifying the form of cicatricial alopecia:
- The first step necessitates taking at least one biopsy
of a 4-mm diameter specimen of skin (of course, inclusive of
subcutaneous tissue) from a clinically active area of scarring
disorder. Since
horizontal sections allow for a close analysis of most of the
affected hair follicles, transverse or horizontal sections are
generally
preferred over vertical sections. The initial biopsy processing
involves staining of transverse sections with hematoxylin and
eosin (H&E).
With only one biopsy performed, submitting it for transverse sectioning
and regular histologic examination will be most productive as transverse
sectioning allows a complete view of most follicles at multiple
levels.
- Alternately, in some clinics two 4mm biopsies are taken
or a single biopsy is cut in half longitudinally and then the
two pieces of skin a processed separately (one transverse section
and
the other bisected vertically). The biopsies may be subjected
to different tests – the transverse section for the common
histology tests and the vertical section for histology as well
as for direct
immunofluorescence (DIF) tests.
In cicatricial alopecia conditions with superficial pustules (pus-filled
eruptions or blisters) and keratotic papules (inflammatory elevation
of the skin), the transverse section sample may not effectively
depict all the pathologic aspects (say for example about the dermoepidermal
junction, papillary dermis and panniculus). Such drawbacks can easily
be overcome by arranging a combination of two or more biopsies for
transverse and vertical sections. Moreover, the adjunctive use of
direct immunofluorescence (DIF) (particularly useful in cases of
primary lymphocytic cicatricial alopecia) is sure to reflect all
the histologic features aid in accurate evaluation of the condition.
- Subjecting the specimens to laboratory tests like elastin,
mucin and periodic acid-Schiff (PAS) stains typically bear significant
results. These distinctive medical tests are sure to supply
additional information for a better analysis.
- Sometimes an additional, optional biopsy from a more
advanced area of alopecia is also recommended. This biopsy is
undertaken
to confirm follicular loss. The test also probes into, and assesses
the pattern of, elastic tissue loss. It thereby establishes the
probability of the re-growth of the hair (rather the hair follicle)
or whether the hair follicles are irreversibly destroyed.
The different forms of lymphocytic cicatricial alopecia are often
detected with overlapping features on routine pathologic examination;
however, they often display distinct, characteristic patterns of
elastic tissue staining. The difference in staining patterns has
been attributed to the disease-related differences in follicular
scar formation as also to the remodeling of the adventitial dermis
(the layer of skin lying below the epidermis and covering the follicle)
following follicular destruction. Thus, the Verhoeffevan Gieson
(VVG) elastin stain is of great significance in differentiating
advanced cases of DLE, lichen planopilaris and pseudopelade of Brocq.
Often DIF of biopsies or fluorescent microscopic analysis of routinely
stained sections is undertaken for tissue stain pattern assessment.
Special stains such as periodic acid Schiff and mucin help reinforce
diagnostic precision. Tissue homogenate cultures for bacteria and
fungi also lead to accurate assessment and diagnosis of cicatricial
alopecia conditions.
Primary cicatricial alopecias and salient clinical features
DLE or Discoid lupus erythematosus – Affects mainly women.
The condition is very much symptomatic with erythematous scaly plaques
and follicular plugs; telangiectases, atrophy and depigmentation
become apparent with time. The disease spreads centrifugally.
Lichen planopilaris. a) Classic – Again affecting mainly
women. The condition is pruritic and is multifocal with many central
alopecic patches.
Follicular hyperkeratosis and erythema appear at the various hair-bearing
margins. b) Frontal fibrosing alopecia – Afflicts postmenopausal
women. The condition is classically characterized by frontotemporal
hairline
recession. c) Graham-Little syndrome – Affects adults in general.
The condition shows patches with follicular hyperkeratosis. The
infection
affects other parts of the body (as the armpit) but it is non-scarring
in these regions.
Pseudopelade of Brocq – A scarring alopecia disorder afflicting
mostly adults. It is an asymptomatic condition, showing no inflammation.
The disorder is marked by the appearance of ivory-white or flesh-colored
small oval-round confetti-like lesions, which later on coalesce
to form large, irregular patches.
Central Centrifugal Cicatricial Alopecia (CCCA) – Primarily
affects black women with the main site of the disorder being the
central scalp. It is a non-inflammatory condition and shows flesh
colored, symmetric patches.
Alopecia Mucinosa – A polymorphous disease affecting all
age groups and is characterized by the appearance of erythematous
plaques with patulous ostia (dilated hair follicle openings), alopecia
areata-like, diffuse or complete alopecia, etc.
Keratosis follicularis spinulosa decalvans (KFSD) – With
the early symptoms appearing in childhood, the disorder shows patchy,
follicular hyperkeratosis and perifollicular erythema.
Folliculitis Decalvans – Again an adult scarring disorder,
it mainly targets the central scalp; it shows grouped follicular
pustules and miliary abscesses at the hair-bearing margin.
Perifolliculitis capitis abscendens et suffodiens – A condition
widespread among black men, it is very painful and often erupts
into blisters and watery contiguous dermal alopecic nodules.
Acne Keloidalis – Another disorder primarily affecting black
men with the occipital scalp showing outbreaks of firm red-brown
papules, papulopustules, nodules and keloidal plaques.
Acne Necrotica – Scarring disorder common among adults with
the infection spreading in the anterior scalp. The condition is
quite painful and is marked by the appearance of papules and punched
out (varioliformis or small pox - like) scars.
Erosive Pustular dermatosis – A condition largely affecting
elderly women; it is asymptomatic. The initial phase is characterized
by the emergence of lesions, which later on turn to crusted plaques
(with flabby pustules underneath the hard crust).
In conclusion, the diagnosis of primary cicatricial alopecias is
unquestionably a very complicated process and a challenging mission.
Yet, only proper diagnosis can determine the course of treatment,
which can further check the cicatricial alopecia condition and initiate
the hair regeneration cycle.
Clinical
approach to diagnosing scarring alopecias references
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