3/22 Hair & Nails Flashcards
(33 cards)
Infundibilum runs from where to where?
opening to sebaceous duct
isthmus runs from where to where?
sebaceous duct to bulge
suprabulbar runs from where to where?
bulge -> bulb
Where is the source of stem cells in the hair follicle?
the BULGE
Name two cell types present in the bulb.
What are they and what are their roles?
contains matrical cells interspersed with melanocytes
matrical cells – undifferentiated cells that make the layers of the hair (medulla, cortex, cuticle)
melanocytes - melanosomes transferred at hair bulb; irreversible loss of melanocytes, resulting in decreased melanin pigment, which results in gray hair
What are the 3 types of hair?
Which one is the most abundant?
terminal - pigmented, long, coarse, has a medulla
vellus - non-pigmented, lacks a medulla; **most abundant**
lanugo - lightly pigmented, fine hair
What type of hair would you see in a patient who is anorexic?
lanugo hair
What are the 3 phases of the hair follicle cycle?
Anagen (growing phase)
Catagen (involution phase)
Telogen (resting phase)
T/F hair grows in the same rate
FALSE.
different body regions spend different amounts of time in anagen, which accounts for variations in hair length
What type of alopecia does this patient have? How do you know?
What are the two variants of this alopecia?
Alopecia Areata
well demarcated, patchy hair loss
two forms:
- totalis (entire scalp)
- universalis (entire body)
variable course with spontaneous remission
What is the name of this alopecia and what is it caused by?
How do you treat it?
Alopecia Areata
unknown etiology, but autoreactive T cells interact with antigens expressed by keratinocytes/melanocytes in the bulb of the hair follicle
Trmt: steroids (uncertain outcomes)
What does this patient have?
alopecia areata
What does this patient have?
How do you know?
What is it caused by?
How do you treat it?
Androgenic Alopecia
Men: frontal hairline recession or bitemporal recession
Cause: androgen-mediated hair loss
increased 5-α-reductase OR increased androgen receptors on scalp -> elevated 5HT -> shortening and narrowing (miniaturization) of hair shaft, resulting in increased telogen phase and decreased hair density
Trmt: Finasteride (blocks 5a-reductase), Minoxidil (Rogaine): vasodilator, hair transplantation, scalp reduction
What does this patient have?
How do you know?
What is it caused by?
How do you treat it?
Androgenic Alopecia
Women: diffuse thinning with preservation of frontal hairline; may result in a “Christmas tree” pattern
Cause: androgen-mediated hair loss
increased 5-α-reductase OR increased androgen receptors on scalp -> elevated 5HT -> shortening and narrowing (miniaturization) of hair shaft, resulting in increased telogen phase and decreased hair density
Trmt: Finasteride (blocks 5a-reductase), Minoxidil (Rogaine): vasodilator, hair transplantation, scalp reduction
What does 5HT do to hair?
causes shortening and narrowing (miniaturization) of hair shaft, resulting in increased telogen phase and decreased hair density
What causes Anagen Effuvium?
Is it reversible?
insult to mitotic & metabolic processes in the hair bulb g shaft thinning, fragility, breakage, or failure of hair formation.
etiologies: chemoRx, radiation, drugs
Total alopecia is common, but total recovery occurs once toxic insult is removed
Your patient comes in after 2 months of chemotherapy and she complains of generalized hair loss.
Her diagnosis is?
Anagen Effuvium
(compare to telogen effuvium - sorry that is the best pic I could find on the web…)
What is Telogen Effluvium?
When does it occur?
How do you diagnose it?
premature entry into telogen phase
occurs 3-5 months after an inciting event
nutritional, childbirth, thyroid disease, androgen excess, massive blood loss, fever, surgery, severe medical illness, Rx (birth control, antidepressants (amitriptyline, nortriptyline), anticoagulants (Coumarin), ß-blockers, Retinoids, Lithium)
Dx: (+) hair pull test
(compare to anagen effuvium - sorry that is the best pic I could find on the web…)
function of nail plate?
keratinized end product
location + function of matrix?
synthesizes nail plate (also contains melanocytes)
located underneath proximal nail fold; contains the lunula – white half-moon area
function of nail bed?
supports nail plate
Name of proximal, lateral, and distal nail folds?
proximal fold: eponychium “cuticle”, protects against injury and infection
lateral fold: paronychium
distal fold: hyponychium
T/F Nails grow at the same rate
False
Fingernails: 0.1 mm/day, 6 months to grow out
Toe nails: ½ the rate of fingernails, 12-18 months to grow out
Onychodystrophy definition?
Give 2 examples
changes in the nail plate shape occurring as a congenital defect or due to any illness or injury that may cause a malformed nail
Ex: psoriasis, lichen planus
