Download Unit 3 Notes

• http://www.anatomy.wisc.edu/courses/gros
s/
Skin Diseases and Conditions
SKIN FACTS…
• Your skin is the largest organ of your body.
• The average adult has 21 square feet of skin
which weights between 7 – 10 pounds, and has
approximately 300 million skin cells.
• On average, each square-half inch of skin
contains: 10 hairs, 100 sweat glands, and 3.2
feet of tiny blood vessels.
• Skin is the thickest on the palms and soles (1.2
to 4.7 mm) and thinnest on the lips and around
the eyes.
SKIN FACTS…
• In your lifetime, you will shed
approximately 40 pounds of skin.
• You have a totally “new” epidermis every
25 to 45 days.
• On a hot day, it is possible to sweat out up
to 7 liters of body water in one day!
SKIN FACTS…
• Your hair appearance is due to the shaft shape
(flat shaft = curly hair, oval shaft = wavy hair,
round shaft = straight hair)
• Hair color itself is due to melanin; gray hair is a
result of a lack of melanin
• Average hair growth is 2 mm per week
• Nails grow at a rate of 0.5 to 1.2 mm per day,
with fingernails growing faster than toenails
• Both hair and nails are simply HEAVILY
keratinized skin!
Blemishes
• Whitehead: occurs at
your sebaceous (oil)
glands when the duct is
blocked by sebum (oils),
dead cells, and/or
bacteria
• Blackhead: when
whitehead oxidizes and
dries out
Athlete’s Foot
• Results from fungus
infection
• Stimulated by warm,
moist environment
• Skin becomes itchy,
red, and peels
Boils
• Results from a deep
bacterial infection
• Inflammation of hair
follicles and sebaceous
glands, common on back
of neck
• Usually filled with white
pus
• Can be caused by ingrown
hairs, splinters, or plugged
sweat glands
Cold Sores
• Also called fever blisters
• Caused by a herpes
simplex virus infection
• Usually occur around the
lips and mouth
• While the sores will heal,
the virus will remain in
the body
Canker Sore
• An oral ulcer caused
by a break in the
mucous membrane
• Many things can
trigger, but most
commonly caused by
some sort of trauma to
the mouth
Warts
• Rough, raised spots on skin caused
by a viral infection, most commonly
HPV
• There are over 130 strains of HPV,
which can affect totally different
areas of the body!
– Feet (plantar warts)
– Genital warts
– Some don’t have any effects at
all!
• Warts can be treated with
medications or by “freezing” it off
Contact Dermatitis
• Itching, redness, and
swelling of the skin
• Caused by exposure of
the skin to chemicals
(irritants)
• Most common example
is poison ivy
Impetigo
• Caused by strep
and staph bacteria
• Pink, fluid-filled
lesions that develop
on skin
• Highly contagious,
usually passed by
contact
• Common in young
children
Psoriasis
– Reddened epidermal lesions
covered with dry, silvery scales
– Scaling occurs when cells in the
outer layer of skin reproduce
faster than normal and pile up on
the skin's surface
– Cause unknown; may be
hereditary
– Attacks triggered by trauma,
infection, hormonal changes,
weather changes, and stress
Frostbite
• Damage due to
extreme cold
• At or below 0oC, blood
vessels in skin
constrict to preserve
body temperature
• If this occurs for long
periods of time, it can
damage the tissue
• Likely to happen
farthest from the heart
(extremities)
Frostbite
Dandruff
• Flaking of the skin, usually at scalp
• Can be caused by dry skin, psoriasis, or
contact dermatitis
Skin Conditions
• Corns
– smaller than calluses
– have a hard center surrounded
by inflamed skin
– develop on parts of your feet
that don't bear weight, such as
the tops and sides of your toes
• Calluses
– develop on the soles of the feet,
especially under the heels or
balls, on the palms, or on the
knee
• Both corns and calluses are
caused by rubbing and friction to
an area, stimulating production of
tough, keratinized skin
Stretch Marks
• Fiber matrix located in dermis (dense
connective tissue) break down
• Creates a lack of support, which leads to
dermal & epidermal stretching
• Caused by both skin stretching, as well as
hormonal changes
Wrinkles
• Loss of strength and
elasticity of skin due to
aging
• Also, lower production of
new cells at stratum
basale layer
• Emphasized by age, sun
damage, repeated facial
movements, and natural
effects of gravity
• More likely to have if fairskinned, or spend time in
the sun
Skin Conditions
• Albinism
– Genetic condition that causes melanocytes in stratum
basale layer not to produce melanin
– Results in light skin tone, blond hair
– Easily sunburned
– Higher risk of skin cancer
– Usually have poor vision, due to a damaged retinal
pigment epithelium, which helps to nourish the retina
– Can be found in ANY racial group
http://abcnews.go.com/2020/overcoming-social-stigma-albinism/story?id=8551660
WEIRD SKIN CONDITIONS
You don’t need to take notes on
these!!! 
“Tree Man”
• HPV causes warts
on the body
• The man with this
condition does not
have an immune
system deficiency
that leaves him
unable to control
the warts
Congenital Insensitivity to Pain
with Anhidrosis
• aka CIPA
• Genetic mutation that disrupts the
development of the small nerve fibers that
carry sensations of pain, heat and cold to
the brain
• Patients feel no pain
• Patients also do not sweat, as they cannot
sense the differences in temperature
Xeroderma Pigmentosum
• Autosomal recessive genetic
disorder of DNA repair
• The ability to repair damage
caused by UV light is deficient
• Leads to skin malignancies at a
young age
• In severe cases, it is necessary to
avoid light completely
• Symptoms include: severe sunburn
after first (and short) exposure,
many freckles, thick & dry skin,
eyes painfully sensitive to the sun
Hypertrichosis
• aka Werewolf Syndrome
• Nearly all the skin of the body
(except palms and soles of
feet) are covered with hair
• There are three types of hair –
scalp, vellus (all over body),
and androgenic (growth
stimulated by puberty and
androgens – genitals, upper lip,
armpits, etc.)
Hypertrichosis
• With hypertrichosis,
vellus hair is also
stimulated by
androgens, leading
to increased growth
Vitiligo
• Disorder that causes
dispigmentation in patches
of skin
• Melanocytes in a particular
area die or are unable to
function
• The precise cause of vitiligo
is not yet fully understood
• There is some evidence
suggesting it is caused by a
combination of
autoimmune, genetic, and
environmental factors
• Common on extremities
Harlequin Icthyosis
•
•
•
•
•
•
Extremely rare genetic disorder where baby
is born with unusually high amounts of
keratin in the skin (400 cases in 50 years)
Skin forms thick, hard, diamond shapes with
deep fissures due to its inflexibility, which
increases their susceptibility to infection
In can also cause the eyes, ears, and mouth
to contract abnormally
The survival rate of children born with this
disease has improved over the years, but
many will die within two days of birth, and
treatment will be required for their entire life
Overnight, they will grow as much skin as a
normal body does in 14 days
Patients must have a daily ritual of
scrubbing and creaming their skin every four
hours, to prevent their skin from cracking
and becoming infected
Aquagenic Urticaria
• Hypersensitivity to
the ions found in
non-distilled water
• Water on the skin
will cause a rash
to appear
Colloidal Silver
• Paul Karason had a
case of stress-induced
dermatitis, but instead
of going and getting
antibiotics, he tried to
treat it with a homeprepared batch of
colloidal silver, an
long-ago abandoned
treatment
And now, back to your
regularly scheduled
programming….
…I mean notes…
Burns
• Burn: tissue damage and cell death
caused by intense heat, electricity, UV
radiation, or certain chemicals
• 2 major issues with burns…
– Body looses fluids containing proteins &
electrolytes, which can cause dehydration &
shock
– Infections – leading cause of death in burn
victims
Burns
• First-Degree Burn
– Only epidermis is
damaged
– Skin is red and
swollen
– EX: sunburn
Burns
• Second-Degree
Burns
– Epidermis and
upper dermis are
damaged
– Skin is red with
blisters
Burns
• Third-Degree Burns
– Destroys entire
skin layer
– Burn is grey-white
or black
Burns
• Burns are considered critical if:
– Over 25% of body has 2nd degree burns
– OR…
– Over 10% of the body has 3rd degree burns
– OR…
– There are third degree burns of the face,
hands, or feet
Skin Cancer
• Cancer: abnormal cell mass
• Two types
– Benign
• Does not spread to rest of the body
– Malignant
• Invade other body areas
Skin Cancer
• Skin cancer is most common type of
cancer
• Most important risk factor is overexposure
to UV radiation
Skin Cancer Types
• Basal Cell Carcinoma
– Least malignant
– Most common type
– Stratum basale altered
so doesn’t form keratin
– Usually treated with
surgical removal
Skin Cancer Types
• Squamous Cell
Carcinoma
– Arises from stratum
spinosum
– Grows rapidly and
attacks lymph nodes if
not removed
– Treated with surgery or
radiation therapy
Skin Cancer Types
• Malignant Melanoma
– Cancer of melanocytes (cells in stratum
basale responsible for melanin production)
– Most deadly of skin cancers
– Attacks lymph nodes and blood vessels
– Begins where there is pigment (ex: moles)
Skin Cancer Types
• ABCD Rule
– Used for recognizing melanoma by looking at
moles
– (A) – asymmetry of mole
– (B) – border irregularity
– (C) – color, multiple colors on mole area
– (D) – diameter is larger than 6 mm (size of
pencil eraser)
Wounds
• A wound is a type of physical trauma
where the skin is torn, cut, or punctured
• There are several different types of
wounds…
Wound types
• Incisions: caused by clean, sharp-edged
object (ex: knife); if only epidermis
involved, called “cut”
• Lacerations: irregular wounds, such as
tearing of the skin
• Abrasion: epidermis is scraped off; often
caused by a sliding fall onto rough surface
(scrape)
Wound Types
• Puncture wound: caused by object
puncturing skin, such as nail or needle
• Avulsion: tearing away of part of skin,
parts of tissue get removed