Alopécia

Perguntas:

Quando notou pela primeira vez a perda de cabelo

Nota perda de densidade de cabelo? Onde?

Nota queda de cabelo? Quando?

Frases de algibeira

Na gravidez o estrogénio compete com o recetor hormonal da testosterona levando a menor efeito da testosterona. Na menopausa, a falta de estrogénio aumenta a ação da testosterona no folículo piloso

O cabelo precisa de grossura para estabelecer pontes de dissulfito que permitam encaracolar

A região do vertex é mais sensível a tratamento hormonal. A região frontal é mais sensível a tratamento com minoxidil

Perucas:

Cláudia Piloto (na Avenida Marques Tomar Lisboa) fez a peruca da Sara Rodrigues (influencer)

Tecnicabelo - loja de próteses capilares ao pé do CHUC

Conceitos teóricos

Folículo piloso

💡

O corpo humano tem aproximada 5 milhões de folículos, incluindo 100.000 a 150.000 que estão no couro cabeludo

Hair Follicle Embryology

O pelo na embriologia surge por proliferação de celulas basais que se chama germe folicular no 3o mes de vida e formam um gomo semelhante aos ninhos de celulas basaloides do CBC

As glandulas apocrinas e sebaceas tem origem na mesma unidade

Follicles evident at 9 weeks gestation on brow, chin and lips

Body hair (lanugo) evident at 4 months in fetus

Lanugo hairs shed at 7-8 mos; no new follicles formed after birth

Follicle types

Lanugo: soft, lightly pigmented, unmedullated, present in aduls only in pathologic states
Vellus: fine, non-pigmented, unmedullated
Terminal: coase, pigmented, medullated

Hair follicle development

Dermal mesenchyme signals overlying epithelium to thicken and form placode

Clustering of mesenchyme and formation of a dermal condensate

Second dermal signal causes epidermis invasion into dermis forming hair germ then hair peg and bulbous peg

Condensate becomes dermal papila

Genes WNT and Beta-catenina: important for dermal signal for follicle development

Normal Hair cycling

Air follicle activity is cyclical

Humans undergo about 10-30 cycles throughout their lifetimes

In childhood, all hairs on the scalp are in sync and shed at the same time but eventually cycles become asynchronous

Hair is replaced every 3-5 years

At any given time 85-90% of hairs are in anagen, 10-15% in telogen and 1% in categen

On 100.000 hair scalp: 13.000 are in telogen and the cycle last 3 months leading to loss of 100-144 hairs per day

Anagénese demora 3 a 10 anos no couro cabeludo, 4 a 14 semanas no bigode)

O cabelo cresce aproximadamente 0,35mm/dia

Estrutura do cabelo

Queratinas do folículo piloso - 2 tipos predominantes

Acidic keratin cluster (type I)

17q12-q21
K31-40

Basic keratin cluster (type II)

12q11-q13
K81-86

Camadas do folículo piloso

Sentido de crescimento das células

As celulas da parte mais profunda queratinizam no sentido vertical para formar a haste pilosa
As células da parte mais superficial queratinizam no sentido horizontal para revestir o lúmen do folículo piloso

Secção longitudinal

Esquema

Infundíbulo

Queratinização = epiderme interfolicular
uppermost part
Greatest inflammation in cicatricial alopecias
From the junction with interfollicular epidermis to opening of sebaceous gland

Istmo

Desde a abertura da glândula sebácea e apócrina até ao músculo eretor do pelo

Trichilemmal Keratinization

Assentada basal

Depois as celulas em vez de achatarem vão aumentado de volume e o citoplasma vai ficando mais palido em direção ao eixo do folículo piloso.

Não existe granulosa

Camada cornea é eosinofílica.

Isto reproduz o que vemos nos quistos triquilémico que chamamos catagénicos

abnormal in congenital atrichia with papules (due to hairless and vitamin D receptor genes mutation)

Also greatest inflammation in cicatricial alopecias

Bulge

lowest part of the hair follicle that does not regress during the catagen phase
where stem cells are
cell at the bulb also replicate and have properties of stem cells, except they regress along with the rest of the lower follicle during catagen

Stem

Celulas mais claras, a basal não é tão basofílica, membrana é mais evidente

Matriz (bolbo)

Celulas mais pequenas, condensas, tem pigmento devido a melanina produzida por melanócitos que também existem
greatest activity and inflammation in alopecia areata

Secção horizontal ou transversal

Esquema

Hair shaft

Hair shaft medulla (central portion)
Hair shaft cortex (forms the bulk of the hair shaft)

Cortex and Medulla - responsible for strength of hair shaft

Hair shaft cuticle (protective layer)

Cuticle - outermost part of hair shaft, responsible for aesthetic appearence

Inner root sheath

The inner root sheath cuticle
Huxley’s layer
Henle’s layer

Outer root sheath → continuous with the epidermis (basal+spinosum layers)

Stratum basale
Stratum spinosum

Pigmentação do Folículo Piloso

Melanosomes in the hair cortex are larger than epidermal melanosomes. There are two main melanin types

Phomelanin (red/yellow)

Pigment abundant in redheads. Common in individuals with recessive mutation in MC1R (predisposed to melanoma)

Eumelanin (black/brown)

Blonde hair is created by low levels of eumelanin NOT high levels of pheomelanin and accordingly browns with age. Natural blonde hair in adulthood is very rare (2%)
Graying - reduction of tyrosinase in hair bulb and melanocyte damage due to reactive O2 species
By age 50, 50% of people have at least 50% of gray hair

Hair differences between ethnic groups

Parameter	Asian	Caucasian	African
Growth rate (um/day)	411 (because more straight)	367	280 (because more curly)
Hair density (hairs/cm2)	175	226	161
Ellipticity (cross section)	90% (circular) - straight	75% (less circular)	60 (oval) - curly

Effects of Medications

Estrogens reduce hair growth rate and prolong anagen

Estrogens responsible for prolonged anagen state in pregnancy

Androgens increase hair growth rate and hair diameter (in androgen-dependent sites)

but decrease hair density in Androgenic alopecia
Hirsutism

Thyroxine promotes growth

Corticosteroids retard/slow anagen onset

Keep in mind when treating patients with inflammatory alopecia with corticosteroids, stop when inflammation is no longer present

Alopecias não cicatriciais

Presença de aberturas foliculares

Eflúvio telogénico | Alopécia sazonal

Pressure induced alopecia

Temporal triangular alopecia

Lipedematous alopecia

Congenital atrichia with papules

Alopecias cicatriciais

Mecanismo

Células estaminais estão junto ao istmo, onde desembocam as glândulas sebáceas e se insere o músculo erector do pêlo

Apresentação clínica e dermatoscopia

Ausência de aberturas foliculares

>3 cabelos a sair do mesmo foliculo - foliculos em doll ou foliculite em tufos

processo de destruição e reparação, destruição e reparação
O normal e 1-3 cabelos emerfem do mesmo folículo
As ovelhas têm >10-20 cabelos do mesmo orifício

Pele com um aspeto atrófico

A tendência é pedir biópsia nas alopecias cicatriciais mas nem sempre é obrigatório especialmente nas alopecias fibrosantes frontais

Pseudopelada de brocq - padrão em pegadas na neve

Padrão inespecífico final de alopecias cicatriciais, nomeadamente líquen plano (mas também lúpus discóide

Linfocíticas

Lichen Planopilaris

Alopecia Fibrosante Frontal

Fibrosing Alopecia in a Distribution Pattern (FADP)

Alopécia por Lupus Eritematoso Discoide

Central centrifugal cicatricial alopecia

Alopécia mucinosa

Keratosis Follicularis Spinulosa Decalvans

Neutrofílicas

Foliculite Decalvante

Celulite Dissecante do couro cabeludo

Mistas

Acne queloide nuca

Inespecíficas

Alopecia neoplastica

Hair Shaft Abnormalities

Generalidades

Look at proximal 1-2 inches of shaft

Cut at base of scalp and place on glass slide with immersion oil

Examine under microscopy with polarized light

Amino acid analysis to detect low sulfur levels

Hair shaft abnormalities with increased fragility

Bubble Hair

Young women

Traumatic hair care with heat

Monilethrix

Autosomal dominant

Hair cortex keratin genes KRT86, KRT81

Other genes: K83, desmoglein 4

Apresentação clínica

Normal hair at birth becomes short, brittle, fragile (pediatric dermatology)

May be just occipital in the beginning

Associated with koilonychia

Trichoscopy

Hair fibers with elliptical nodes

Perifollicular erythema and follicular hyperkeratosis

Pili torti

Flattened shaft with twisting of hair on its own axis (3-10 twists)

Torcinos em torno do próprio eixo

Hair appears spangled

Associated with (daí considerar pedir consulta de genética)

Keratosis pilaris

Nail dystrophies

Dental abnormalities

Screen for sensorineural hearing loss (Bjornstad Syndrome - BCS1L)

Menkes disease (ATP7A)

Crandall syndrome (Bjornstad + hypogonadism)

Bazex Dupré Christol syndrome

Hypotrichosis with juvenile macular dystrophy (P-cadherin)

Laron syndrome

Ectodermal dysplasias

Mitochondrial disorders

Urea cycle defects

Anorexia nervosa (acquired)

Oral retinoids (acquired)

Trichorrhexis invaginata

AKA bamboo hair, cabelo em taça de golf

Intussusception of distal shaft into proximal shaft

Defective cornification of the cortex

Seen in Netherton syndrome (SPINK5)

Associated with icthiosis and eczema

Trichorrhexis nodosa

Most common structural hair abnormality

Easy hair shaft fracture with splaying out of ends

Common in people with curly hair!

Proximal (years of straightnening), distal (acquired cuticular damage), circumscribed (scalp, mustache or beard)

Congenital or acquired

Congenital associations

Argininosuccinic aciduria
Citrullinemia
Menke’s kinky hair syndrome
Trichothiodystrophy
Nethertons’s syndrome

Acquired trichorrhexis nodosa (ATN)

Very common
ATN is recurrent hair breakage that occurs as a result of damaging hair practices.
Common culprits include undermoisturized naturally curly hair, home relaxers, overuse of thermal straightening tools or extensions
Patients will often complain of lack of hair growth - May complain cannot grow hair past a certain point
Can involve all parts of the scalp but nape of the neck is often affected (area with most friction likelyhood)
Treat with healthy hair practices

Hair shaft abnormalities without increased fragility

Acquired progressive kinking of the hair

Loose Anagen Hair Syndrome

Cabelo mais fino e encaracolado

anomalia na estrutura da bainha radicular interna do folículo piloso, impedindo que o fio se fixe adequadamente

Em crianças

Temporário, o cabelo acaba por crescer normal

Pili annulati

Pili bifurcati

Pili multigemini

Spun-glass hair (uncombable hair)

Wooly hair

Outros

Oleosidade couro cabeludo

Isotretinoína 20mg 1-2/sem

Não precisa de análises

Red Scalp Syndrome

Clínica

Disestesias, prurido, ardor e dor

Fisiopatologia

Teoria de “rosácea do couro cabeludo”

Tratamento

Responde à doxiciclina
Evitar corticoides (pode fazer deflazacorte no início)
Cutalgan
Doxiciclina
Minox 2mg