Transcript CH.-17-Skin
CH. 17 DISEASES OF
THE SKIN
SWCTA
Dr. Michael J. Georges
I. FUNCTIONS OF THE SKIN
The skin or the integument is a vital organ
A “protective wrap”
Regulates body temperature
Senses pain
Keeps harmful substances & microorganisms
from entering body
Provides a shield from harmful effects of the
sun
Largest organ of the human body
I. FUNCTIONS OF THE SKIN
Indicates malfunction within the body through
color changes
Cyanosis (blue) is lack of O2-cardiovascular
problem
Jaundice (yellow) – indicates liver disease
from accumulation of bilirubin in the blood
Abnormal redness – due to polycythemia,
carbon monoxide poisoning, & fever
Pallor (whitening) may indicate anemia
II. STRUCTURE OF THE SKIN
Each layer of skin performs specific tasks
OUTERMOST layer is the EPIDERMIS
Consists of stratified or squamous epithelium
Top layer of epidermis contains KERATIN – a
tough, fibrous protein that protects skin from
harmful substances
Bottom layer of epidermis contains MELANIN
– dark pigment in skin that protects body from
harmful rays of the sun
II. STRUCTURE OF THE SKIN
DERMIS – “True Skin”
SUBCUTANEOUS –lies
lies below the epidermis
Composed of
connective tissue
Supports blood & lymph
vessels, elastic fibers,
nerves, hair follicle,
sweat glands &
sebaceous (oil) glands
under the dermis
Connects the skin to
underlying structures
(i.e. muscle, fat)
Contains adipose (fat
cells) tissue – helps
insulate body from cold
& heat
Fig. 18-1 pg. 397
Structure of the Skin
III. CLASSIFICATIONS OF SKIN
DISEASES
Skin diseases are identified and classified
according to characteristic lesions (size,
shape, color & location) and other S & Sx’s
Fig. 18-2 Skin signs pg. 398
PRURITIS – itching
EDEMA – swelling
ERYTHEMA – redness
Inflammation –usually accompany lesions
and are helpful in making a diagnosis (DX)
III. CLASSIFICATIONS OF SKIN
DISEASES
VESICLES – small blister-like eruptions or
larger fluid-filled lesions called bullae.
PUSTULES – lesions that contain pus
MACULAR – flat lesions
PAPULAR – raised lesions
ERYTHEMATOUS – reddened area due to
inflammation &/or injury
Nodules & tumors – hard to the touch
Pruritis – itching, which accompanies many
skin diseases, especially allergic & parasitic
IV. INFECTIOUS SKIN DISEASES
BACTERIAL
IMPETIGO – is acute, contagious &
common in children
Caused by streptococcal & staphylococcal
organisms in the nose & passed to the skin
Erythema, reddened area develops and
oozing vesicles and pustules form
Area ruptures & yellow crust covers lesion
Face & Hands most frequently affected
Fever & enlarged lymph nodes may present
Wash with soap & H20, dry, keep open to air
IV. INFECTIOUS SKIN DISEASE
BACTERIAL
ERYSIPELAS – inflammatory skin
infection caused by streptococci
Commonly appears on face, arm or leg
Infection begins where skin is broken
Shiny, swollen, red rash initially develops,
often with small blisters
Red rash is hot & tender to touch
Fever & chills present when infection severe
Treatment with antibiotics (ABX) when severe
IV. INFECTIOUS SKIN DISEASE
BACTERIAL
CELLULITIS - spreading infection of the
skin most often caused by streptococcus
Most common on the legs and begins with
skin damage
Affected area is swollen, red, & tender
Sx’s may include fever & chills
Treatment (TX)– prompt TX prevents the
spread of infection to the blood & vital organs
IV. INFECTIOUS SKIN DISEASES
BACTERIAL
FOLLICULITIS – inflammation of hair follicles by staphylococci
Small number of pustules develop in follicle
Commonly occurs in young men and affects thighs, buttocks, beard
& scalp (Fig.18-4 p.400)
TX-severe cases require oral ABX
CARBUNCLES- clusters of boils.
Arise in cluster of hair follicles
Develop & heal more slowly than furuncles
Mostly appears in men and commonly found on back of neck
FURUNCLES – “boils” are large, tender, swollen raised lesions
caused by staph (Fig. 18-5 p. 401)
Appears in hair follicles on face, neck, breast, or buttocks
The core of furuncle is necrotic & liquefies to form pus
TX-moist heat, antiseptic skin cleansing, oral ABX, I & D
VIRAL SKIN INFECTIONS
Most common viruses cause cold sores or fever
blisters & warts
HERPES SIMPLEX – causes cold sores &
fever blisters (Fig. 18-6 p. 401)
VERUCCA VULGARIS – causes WARTS
Keratinocytes proliferate making the surface rough
Most common in children & young adults
Affects mostly the hands (Fig. 18-7 p.402)
Multiple & CONTAGIOUS – spread by scratching
Reoccurs if virus remains in body, not serious
May disappear spontaneously, not painful
Should only be removed by an M.D.
VIRAL SKIN INFECTIONS
WARTS
PLANTAR WARTS – found on the SOLES
OF THE FOOT
GROWS INWARD, unlike other warts on the
body which grow outward (elevated)
Painful, due to pressure on the soles of the
foot when walking or standing
Difficult to remove permanently
GENITAL (VENEREAL) WARTS – very
serious & difficult to remove (CH. 15)
VIRAL SKIN INFECTIONS
FUNGAL
DERMATOPHYTES (FUNGI) – live on the
dead, top layer of the skin
Symptoms may or may not appear
Serious infections – itching, swelling, blisters
& severe scales
Minor infections – mild irritation & swelling
VIRAL SKIN INFECTION
FUNGAL
RINGWORM (TINEA) –
caused by many
different fungi.
Classified by its location
on the body (Table 18-1)
Found on warm, moist areas
of the body and hairy skin on
head, groin, arms, & legs
SX’s – mild scales, cracking
skin, to painful raw rashes
TX- keep area clean & dry,
apply antifungal meds.
TINEA CORPORIS –
Body ringworm, smooth
areas, arms, legs, body
TINEA PEDIS –
”ATHLETES FOOT”
soles, btwn toes, toenail
TINEA CRURIS –
“JOCK ITCH” groin &
upper thighs
TINEA CAPITIS –
“SCALP” ringworm.
HIGHLY CONTAGIOUS
PARASITIC INFESTATIONS
3 Categories
PEDICULOSIS – Louse (lice) infestations
HEAD LICE – common among children
Spread from head to head (direct)
Indirect – combs, scarves, hats, bed linen,etc
Itching – caused by saliva of lice penetrating skin &
engorging on human blood
Scratching – can open up skin to other invading
organisms
Adult head lice – hard to see, lay white eggs “NITS”
along hair shaft
TX – Medicated shampoo followed by fine tooth comb
to remove nits
PARASITIC INFESTATIONS
PUBIC LICE – infest pubic hair and generally
spread by sexual contact.
Lice does not spread other STD’s
TX – RX Cream
BODY LICE – most common among
underprivileged, transient people.
Lice CAN SPREAD DISEASE – such as
typhus epidemics among soldiers during war
Prevention – good grooming & hygiene
PARASITIC INFESTATIONS
SCABIES “THE ITCH” – caused by a parasitic
MITE
HIGHLY CONTAGIOUS
Female mite – burrows into skin folds of groin, under
breasts, between fingers & toes. Lays eggs in tunnels
of folds, eggs hatch, cycle begins again
Spread via close contact & linked to other VD’s
Blisters & pustules appear
Itching – caused by hypersensitivity to mite & opens up
skin to other bacterial infections
Epidemics common in camps & barracks (poor living)
TX & Recovery – Hot baths & scrubbing & meds.
Underwear & bedding changed & washed frequently.
V. HYPERSENSITIVITY OR
IMMUNE DISEASES OF THE SKIN
HYPERSENSITIVITY – ALLERGIC reactions
of the skin. Emotional stress may trigger or
exacerbate an allergy-caused skin disease.
INSECT BITES – Bites & stings can produce
local inflammatory reactions.
Acute reactions – hives
Chronic reactions – papules (solid elevations)
Bullous - blisters
HYPERSENSITIVITY OR IMMUNE
DISEASES OF THE SKIN
URTICARIA (HIVES) – VASCULAR
REACTION OF THE SKIN TO AN
ALLERGEN
WHEALS – lesions round elevations with red
edges & pale centers
Extremely itchy
Histamine released – cause blood vessels to
dilate, followed by edema & intense itching
Common causes – food, allergens & stress
TX- steroids, antihistamines, topical creams
HYPERSENSITIVITY OR IMMUNE
DISEASES OF THE SKIN
ECZEMA – AKA CONTACT DERMATITIS is a non
contagious inflammatory skin disorder.
Cause – sensitization that develops from skin contact
with various agents, plants, chemical, & metals.
Poison ivy and poison oak, dyes used for hair &
clothes, metals, particularly nickel used in jewelry.
S & Sx’s – Vesicles & bullae appear with itching.
Scaly crusts form on ruptured lesions.
Scratching – causes the lesions to burst & ooze
which spreads the eczema.
TX – Corticosteroids to reduce inflammation
Fig. 18-10 p.406
HYPERSENSITIVITY OR IMMUNE
DISEASES OF THE SKIN
POISON IVY – causes
extreme itching with blisters
and hive-like swelling typical
of a contact dermatitis
Develops in few hours
or few days
Severity – depends on
amount of plant resin on skin
& sensitivity of ind.
TX- Topical cortisone-type
cream, gel or spray.
Table 18-2 Common rashes
caused by Drugs p. 407.
DRUG ERUPTIONS –
Adverse drug reactions
manifest more often on the
skin than any other organ
system.
Topical drugs – mild pimples
over sm. Area to peeling of
the skin
Serious reactions may lead
to anaphylaxis shock or
death.
Most common offending
drugs are penicillin, sulfa,
morphine, codeine, etc.
VI. BENIGN TUMORS
NEVUS (MOLE) – small, dark skin growth
that develops from pigment-producing cells or
melanocytes.
Appear flat or raised & vary in size
Most people have about 10 moles
Usually harmless, but can become malignant
Sudden changes in moles such as
enlargement, irregular border, darkening,
inflammation & bleeding are warning signs of
malignancy (Fig. 18-15 & 18-16 p. 409)
VII. SKIN CANCER
BASAL CELL CARCINOMA – most common skin
cancer. Slow growing, generally non-metastasizing
(spreading) tumor.
Develops on face of light skinned people exposed to
sun
Lesions begin as a pearly nodule with rolled edges
that may bleed and form a crust
Ulceration occurs and size increases if neglected
TX- surgical removal, cauterize, or radiation.
Fig. 18-17 to 18-19 p. 410.
VII. SKIN CANCER
SQUAMOUS CELL CARCINOMA – more serious
than basal cell carcinoma because it grows more
rapidly, infiltrates underlying tissue, and metastasizes
in lymph system.
Malignancy of the keratinocytes in the epidermis of
people who are excessively exposed to sun.
Lesion is crusted nodule that ulcerates & bleeds.
May develop in any squamous epithelium of the body
including the skin or mucous membranes lining a
natural body opening (mouth, nose, ear, etc.)
TX – complete surgical removal or radiation therapy.
VII. SKIN CANCER
KAPOSI’S SARCOMA – Purplish neoplasm
of the lower extremities.
Lesions – red to purple lesions varying from
macules (flat) to nodules (hard nodes)
This skin cancer is epidemic in AIDS patients
Cause of 11% of AIDS-related deaths
VII. SKIN CANCER
MALIGNANT MELANOMA – the MOST SERIOUS
skin cancer. Arises from the melanocytes of the
epidermis.
HIGHLY MALIGNANT and metastasis is early
Sometimes develops as a mole that changes in size,
color & becomes itchy & sore.
TX-surgical removal with the surrounding lymph
nodes to reduce metastasis
Prognosis-depends on depth of infiltration, previous
metastasis, & how completely the tumor is removed.
Fig. 18-21 Malignant melanoma spread to brain.
VIII. SEBACEOUS GLAND
DISORDERS
Hyperactivity of the sebaceous glands causes acne
and chronic dandruff. Raised, horny lesions result
from an excessive production of keratinocytes.
ACNE (VULGARIS) – blackheads, pimples and
pustules.
Affects many adolescents, about 80% between the
ages of 12 – 15.
Mild form – non-inflammatory acne with few white &
black heads.
Inflammatory acne – severe breakout of pus-filled
pimples & cysts that cause deep pitting & scarring
SEBACEOUS GLAND DISORDERS
ACNE
Result of hormonal changes
that occur at puberty
Increased level of estrogen &
testosterone stimulates not only
growth at this time but also
glandular activity
SEBACEOUS GLANDS
increase secretion of SEBUM,
the oily fluid that is released
through the hair follicles.
If duct becomes clogged by dirt
or make-up, the sebaceous
secretion accumulates, causing
a little bump or whitehead
Sebaceous accumulation at the
surface becomes oxidized and
turns black, causing a
blackhead
Blackheads should not be
squeezed or picked because
the broken skin offers entry of
bacteria that’s always present
on the skin
Once pyogenic (pus producing)
bacteria enters the skin, pus
forms and a pimple or pustule
“whitehead” results.
Squeezing the pimple spreads
the infection
TX- daily frequent & thorough
washing to remove excess oil &
bacteria. Dermatologist may
prescribe topical or oral ABX.
SEBACEOUS GLAND DISORDERS
SEBORRHEIC DERMATITIS
KNOWN AS “CHRONIC DANDRUFF”
CAUSE-same as acne, an excessive
secretion of sebum from the sebaceous gland
SX’s- Oily scalp, with scales that form from
excess sebum
Can spread to face, ears & eyebrows
TX – frequent shampooing with medicated
shampoo and thorough brushing of hair
loosens dandruff scales & washes out easily
SEBACEOUS GLAND DISORDERS
SEBACEOUS CYSTS-
ACNE ROSACEA-
formed when gland duct
becomes blocked, sebum
accumulates under the
skin surface, forming a
lump.
These cysts are NOT
considered serious, but
they can rupture, allowing
bacteria to enter.
TX-incision & drainage or
surgical removal
condition that appears
during or after middle age
in persons with fair skin.
Usually cheeks, chin &
nose develop tiny pimples
and broken blood vessels
that eventually thicken and
gives the nose a bulbous
appearance.
Cause: NOT KNOWN
TX – Responds well to
topical ABX
IX. METABOLIC SKIN
DISORDER
PSORIASIS – a superficial recurring idiopathic
(unknown cause) skin disorder characterized by an
abnormal rate of epidermal cell production and
turnover.
Rapid replacement of epidermal cells results in
formation of red, round, raised lesions with silvery
scales.
Occurs on elbows, knees, & scalp (mistaken for
severe dandruff) which flairs up and has periods of
remission & exacerbation
Cause – NOT KNOWN
TX-application of emollient cream, topical & oral
steroids, coal tar cream & UV light. Severe psoriasis
can be treated with anticancer meds.
X.
PIGMENT DISORDERS
The main skin pigment, MELANIN, is interspersed among other cells
in the epidermis. Skin color varies from light to dark depending on the
number of melanocytes. Melanin production normally increases with
exposure to the sunlight causing tanning.
ALBINISM –A rare
INHERITED disorder in
which NO MELANIN is
formed
An Albino person has white
hair, pale skin, & pink eyes
Because melanin protects
the skin, Albinos are prone
to sunburn and skin cancer
VITILIGO – A loss of
melanin resulting in white
patches of skin.
White patches are well
defined (demarcated) and
may cover large parts of the
body
Hypo-pigmentation is most
striking in dark-skinned
people
The affected skin is prone to
sunburn
NO CURE
TX - SUNSCREEN
XI. DIAGNOSTIC TESTS FOR
SKIN DISEASES
Skin conditions are normally identified by its
characteristics such as size, shape, color, location &
presence or absence of systemic S&SX’s
Culturing the purulent lesion usually identifies the
bacterial, fungal, and viral infections.
Culture grows & specimen is identified under a
microscope
Biopsies (tissue sample) are usual for neoplastic
(abnormal new growth) lesions, chronic eruptions,
and nodular lesions
Excised tissue is about 1/8 inch in diameter and is
examined under a microscope.
XII. SUMMARY
The skin protects the body from various elements in the
environment, it can become diseased in many ways.
Skin infections may be caused by bacterial, viral, fungal &
parasitic infestations.
Skin diseases frequently manifest allergies due to
hypersensitivity or immune conditions.
Abnormal growth or neoplasms may be benign or malignant and
range from the common mole to malignant melanoma (skin
cancer).
Skin lesions take many forms, each of which is significant
in diagnosing the disease. The location of the lesion,
whether it tends to recur, and whether it itches, are also
factors in the diagnosis.
To rule out systemic conditions, blood tests and other laboratory
tests may be performed.