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Secondary
scarring alopecia from pattern hair loss
Pattern hair loss can sometimes be regarded as a secondary scarring
alopecia condition affecting both sexes. Androgenetic alopecia per
se is a typical condition characterized by miniaturization of the
hair follicles (basically in the central scalp) and shortening of
the anagen hair follicle growth phase. The cicatricial alopecia
is regarded as an upshot of the anomalous anagen growth phase of
the hair cycle / telogen resting phase of the hair cycle ratio,
but the true cause behind the inflammation promoting the scar tissue
formation is yet to be fully interpreted.
Histological features reflect all the changes. Deposition of a
mild perifollicular lymphohistocytic infiltrate is observed around
the upper follicle in about one-third of patients with androgenetic
alopecia. Moderate infundibular lymphocytic folliculitis and loose
perifollicular lamellar (arranged in thin plates or scales) fibrosis
is seen in 36% of cases of androgenetic alopecia, but in individuals
who do not have androgenetic aloepcia, the frequency is only around
10%. Histological tests also give evidence for hyalinization (the
formation of hyalin; hyaline is a translucent albuminoid substance)
of fibrous tracts and reduction of adnexal structures (appendages
of organs).
Another form of cicatricial alopecia typified by the occurrence
of perifollicular erythema (a name applied to redness of the skin
produced by congestion of the capillaries) and follicular keratoses
(benign but pre-cancerous lesions of skin associated with ultraviolet
irradiation) restricted to the area of pattern hair loss has been
identified very recently. Biopsies of the skin samples collected
from the region bear proof of the presence of a lymphohistiocytic
infiltrate around the isthmus and infundibular areas. The other
traits of this scarring alopecia are follicular interface dermatitis
and focal liquefactive degeneration of the basal cell layer of the
outer root sheath with apoptosis (an active process requiring metabolic
activity by the dying cell, often characterized by cleavage of the
DNA (Deoxyribo Nucleic Acid) into fragments that give a so called
laddering pattern on gels) of follicular keratinocytes (epidermal
cells that synthesize keratin and undergo characteristic changes
as they move upward from the basal layers of the epidermis to the
cornified or horny layer of the skin).
Secondary
scarring alopecia - senescent alopecia
Senescent or senile alopecia is a unique alopecia that displays
a very slow rate of progression. The afflicted group is usually
elderly people (in their 70s and 80s) and is characterized by diffuse
thinning of the scalp hair. The condition shows no signs of scalp
dermatitis or inflammation of the skin. Biopsy tests show many empty
fibrous tracts and minimal perifollicular inflammation. It is not
clear whether senescent alopecia involves androgen hormones or not.
However, it is generally regarded as a form of hair loss that is
distinct from common androgenetic alopecia. Stem cell depletion
(resulting from inflammation) is believed to be the causal factor.
It may be that senescent alopecia is simply an example of the hair
follicle stem cells becoming “worn out” with age and
less capable of multiplying, forming a hair follicle, and producing
hair fiber as they once did.
Secondary
scarring alopecias from bullous disorders
Cicatricial Pemphigoid
Cicatricial pemphigoid (a chronic disease that produces adhesions
and progressive cicatrization and shrinkage of the conjunctival,
oral, and vaginal mucous membranes) is a bullous disorder, which
manifests itself as a patchy alopecia with both firm and flaccid
bullae (blister or vesicle) scattered all over the scalp skin. In
the advanced stages, the scalp skin becomes dry and resembles parchment-paper.
A localized variant of the disorder, Brunsting-Perry syndrome, usually
attacks when patients are in their 50s or 60s. Patients suffering
from this syndrome are subject to pruritus (intense itching without
any eruptions) of the head and neck region. No mucosal lesions are
observed in the localized form.
Bullous pemphigoid, according to laboratory tests and analysis,
is a unique condition and reveals typical histologic features such
as the presence of neutrophil-rich, eosinophil-rich, or non-inflammatory
sub-epidermal bulla. Prominent festooning of the papillae (the superficial
projections of the dermis/corium that interdigitate with recesses
in the overlying epidermis; they contain vascular loops and specialised
nerve endings, and are arranged in ridge-like lines) and superficial
fibrosis distinguishes this form of hair disorder from the other
alopecia conditions. Diagnostic tests, such as, DIF (Direct Immunoflourescence)
provides proof of the existence of immunoreactants (both linear
and circulating) – C3, IgG, IgA, or IgM at the basement membrane
zone of the epidermis, follicle as also of sweat ducts.
A reasonable amount of information regarding the treatment of cicatricial
pemphigoid is available. Corticosteroids, cytoxic agents, dapsone,
intravenous immunoglobulin, plasmapheresis and sulfapyridine can
control the spate of cicatricial pemphigoid and restore normalcy.
In doing so this can also help prevent the progression of cicatricial
alopecia associated with bullous pemphigoid.
Epidermolysis Bullosa
Epidermolysis bullosa is a group of inherited disorders that outwardly
manifest themselves in the forms of bullae, erosions, and secondary
infection of the scalp. All the different types of epidermolysis
bullosa – whether the acquired form or the simplex type, the
junctional type or the recessive dystrophic (caused by genetically
determined degeneration) – have been broadly grouped and linked
with cicatricial alopecia by scientists and dermatologists.
Weary-Kindler Syndrome
Weary-Kindler syndrome is another bullous disorder that affects
all age groups. The condition is represented by the eruption of
blisters in early childhood. When the condition aggravates it is
characterized by the emergence of such features as mucosal erosions
(erosions of lubricated inner lining of membrane), nail dystrophy,
numerous keratoses resembling seborrheic keratosis, poikiloderma
(a variegated hyperpigmentation and telangiectasia of the skin,
followed by atrophy) with photosensitivity, pseudoscleroderma and,
of course, scarring alopecia.
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