Skin Disorders and Diseases
Skin
• Accounts for 15% of body weight
• Largest organ - 21ft2
Homeostatic Imbalances of the Skin
• Can develop more than 1000 conditions
• Most common
– Bacterial
– Viral
– Yeast infections
• Less common…more damaging
– Cancer
– Burns
Infections
Athletes foot
Caused by fungal infection
Boils and carbuncles
Caused by bacterial infection
Cold sores
Caused by virus
Ring Worm
Caused by fungal infection
Infections and allergies
Decubitus Ulcer (Bed Sore)
Pressure/infection
Contact dermatitis
Exposures cause allergic reaction
Urticaria
Hives
Caused by stress or allergin
Impetigo
Caused by bacterial infection
Psoriasis
Cause is unknown
Triggered by trauma, infection, stress
What Does It Look Like?
• Find a spot (mole, beauty mark, etc…)
somewhere on your body
• Draw what it looks like on your paper,
including the color
• Describe the texture
• Measure in mm
Skin Cancer
Cancer – abnormal cell mass
Two types
Benign
Does not spread (encapsulated)
Malignant
Metastasized (moves) to other parts of the body
Skin cancer is the most common type of cancer
Overexposure to UV radiation – disables tumor
suppressor gene (p53)
Basal Cell Carcinoma
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Most common & least malignant
Occurs in stratum basale
Slow growing
Cells proliferate & invade the dermis and
hypodermis
• Usually appear on sun-exposed face
• Symptoms
– pale marks, reddish patches that recur, sores that don’t
heal, shiny bumps, round & smooth growths with a
raised edge
Squamous Cell Carcinoma
• Next most common
• Arises from keratinocytes of the stratum
spinosum
• Tends to grow rapidly & metastasize to lymph
nodes if not removed
• Early removal allows a good chance of cure
• This kind can recur, so avoid sun and follow-up
visits
• Symptoms
– similar to basal, bleeding wart, scaly reddened
elevation, appears on scalp, ears, and lower lip
Melanoma
• Most dangerous – cancer of the melanocytes
• Metastasizes rapidly to lymph and blood vessels
• Resistant to chemotherapy
• Appear spontaneously OR preexisting mole
• Appears as a spreading brown to black patch –
moves to surrounding lymph & blood vessels
• Key – EARLY DETECTION!
Detection Uses ABCD rule
A = Asymmetry
Two sides of pigmented mole do not match
B = Border irregularity
Borders of mole are not smooth
C = Color
Different colors in pigmented area
D = Diameter
Spot is larger then 6 mm in diameter
Using your Chromebook answer
the question at the following link:
http://pollev.com/andreaferris121
Answer: Contact Dermatitis
Eczema = Atopic Dermatitis
Objectives
• Students will be able to distinguish between a
hand full of genetic defects of the
Integumentary System.
• Students will be able to identify the
characteristics of the 3 types of burns, as well
as use the rule of nines to determine the
severity of a burn.
• Students will be able to describe the stages of
skin development.
Genetic Disorders
• Vitiligo
– Loss of pigment
– White patches
• Porphyria
– Vampire Disease
– Build up of chemicals
– Heme production
altered
• Albinism
– Defect in melanin
production
– Fair complection &
traits
• Mongolian Spot
– Entrapment of
melanocytes during
migration = more
dark pigment
Genetic Disorders
• Epidermolysis
Bullosa
– Severe blisters
– Fusion of parts
Striae AKA Stretch Marks
• Silvery, white scars
• Dermis is torn or
stretched
Skin Homeostatic Imbalances
Burns
Tissue damage and cell death caused by heat,
electricity, UV radiation, or chemicals
Associated dangers
Dehydration
Electrolyte imbalance
Circulatory shock
Could lead to renal failure
Slide 4.25
Burns
• Immediate threat – catastrophic loss of body
fluids containing proteins & electrolytes
• Must replace lost fluids immediately!!!
• Leading cause of death in burn victims –
infection (once initial crisis had passed)
• Use rule of nines for extent of the burns
Rules of Nines
Way to determine the extent of burns
Body is divided into 11 areas for quick
estimation
Each area represents about 9%
Slide 4.26
Rule of Nines
Severity of Burns
First-degree burns
Only epidermis is damaged
Skin is red and swollen
Symptoms
localized redness, swelling, & pain, NO blisters
Heals in 2-3 days
Example: sunburn
Slide 4.27
Severity of Burns
Second degree burns
Epidermis and upper dermis are damaged
Skin is red with blisters
Heals in 3 – 4 weeks, minimal scarring
Slide 4.27
Third-degree burns
Destroys entire skin layer
Burn is gray-white , cherry red, or black
Area is not painful - why???
Infection is common because cells of the
immune system can’t get to the tissue (no
blood vessels)
• Skin grafting is usually necessary
– 1. remove burned skin
– 2. flood area with antibiotics and cover the burned area
– 3. healthy skin is transplanted to the burned site
Critical Burns
Burns are considered critical if:
Over 25% of body has second degree burns
Over 10% of the body has third degree burns
There are third degree burns of the face, hands,
or feet
There are burns in the genital area.
Slide 4.28
Development of Skin
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Epidermis develops from ectoderm
Dermis & Hypodermis – mesoderm
By end of 4th month – skin is well formed.
During the 5th & 6th month – fetus is covered
in downy coat = lanugo coat
• Lanugo coat is shed by 7th month
• When born – covered in vernix caseosa =
white, cheesy-looking substance produced by
sebaceous glands
Tell Your Classmate!!!
• Turn to a classmate and tell him or her the
most interesting thing you learned today.
• Make sure to explain why you thought it to be
interesting!
READ ON YOUR OWN
• Make sure to read pages 124-128 in your
textbook.
• Look for study guide answers on Twitter.
• Bring all your foldables to class on
Wednesday/Thursday.