Download Diseases of Skin and Eyes

Layers of skin (3)
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Epidermis
Dermis
Subcutaneous
◦ Gives rise to hair follicles
and sebaceous glands (oil
and sweat)
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Protection from
environmental factors
Barrier to infection
Sensitive to pressure
◦ Pacinian corpuscles
 Nerve endings for light
touch/light sensation –
hairs standing on end
when excited/nervous
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Break or breach of the skin
Associated with systematic
infection
Toxin mediated by
microorganism that is
actually infecting some
other site of body and
producing toxins that effect
the skin
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Break or breach of the
skin
◦ Enter the body through
carbuncles etc... usually
associated with puss
Associated with systematic
infection – see symptoms on
the skin
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Chicken pox
Herpes
Syphilis
Small pox
Toxin mediated by
microorganism that is
actually infecting some other
site of body and producing
toxins that effect the skin
◦ Scarlet fever
 Streptococcus pyogenes is
causative agent
◦ Scalded skin syndrome –
like third degree burns
 Staphylococcus aureus is
causative agent
Normal flora on our
skin- we want to have
these microorganisms
because they outcompete
most other invading
microorganisms for space and
nutrients.
◦ Staphylococci
◦ Yeast
◦ Gram negative enterics
◦ Diptheroids
Variety and amount of
microorganisms on our
skin is affected by
temperature
moisture
pH
amount of sweat
produced
◦ chemicals excreted
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 Oleic acid
 Urea
 Sebum
Most common causes of skin
infections are Staphylococcus
aureus and Streptococcus
pyogenes .
Clinically Presented as:
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Carbuncles
Boils
Pimples
Furnucles
Most common skin infection
in children.
Signs and symptoms: local
infections, characterized by
isolated pustules that become
crusted and rupture
Transmission: mostly through
contact, bacteria penetrate skin
through minor abrasion or insect bite
Causative agent: S. pyogenes
Tx: Topical antibiotic-Bactroban,
Systemic antibiotics-Cephalexin,
Erythromycin
Infection of hair follicle
Signs and symptoms: rash,
pimples surrounding hair follicle,
itching, reddened skin area
Transmission: result of injury or
damage to hair follicle
Causative agent: S. aureus
Tx: Topical antibiotic-Bactroban,
Systemic-Erythomycin
Severe type of tissue infection that can
involve the skin, subcutaneous fat, the
muscle sheath (fascia), and the muscle. It
causes gangrenous changes, tissue death,
systemic disease, and frequently death.
Signs and Symptoms:
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Severe pain in the area
swelling in the area
Discoloration in the area
May appear reddened, bronzed,
bruised, or purple (purpuric)
Progresses to dusky, dark color
Bleeding into the skin
Visible dead (necrotic) tissue
Skin color, patchy
Skin breaks (open wound)
Skin around the wound feels hot and
looks reddened, raised, or discolored
(inflammed)
Oozing fluid ranging from yellowish
clear or yellowish bloody to pus-like
fever
General ill feeling (malaise)
Causative Agent:
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Streptococcus pyogenes
Mycobacterium ulcerans
Vibrio vulnificus)
Tx: Powerful broad-spectrum antibiotics
must be administered immediately. They
are given intravenously (in a vein) to attain
high blood levels of the antibiotic in an
attempt to control the infection. Surgery is
required to open and drain infected areas
and remove (debride) dead tissue.
Skin grafts may be required after the infection is
cleared. If the infection is in a limb and cannot be
contained or controlled, amputation of the limb
may be considered. Sometimes pooled
immunoglobulins (antibodies) are given by vein to
help fight the infection.
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Fatalities are high
A type of (cellulitis) skin infection
◦ Signs and Symptoms:
 An erysipelas skin lesion typically
has a raised border that is sharply
demarcated from normal skin. The
underlying skin is painful,
intensely red, hardened
(indurated), swollen, and warm.
 Facial erysipelas classically involve
the cheeks and the bridge of the
nose.
 Blisters may develop over the skin
lesion.
 Fever and shaking chills are
common
◦ Causative Agent: S. pyogenes
Etiology Bacillus anthrax
Gram-positive
Endospore forming
3 clinical manifestations
◦ Cutaneous
◦ Pulmonary
◦ GI
Flu like symptoms
Malignant pustule called
eschar – surrounded by
swelling (edema) redness
black in the middle
becomes a scab.
Not common – associated
with an occupation or
hobby that involves
livestock or ranching
◦ Spores can be inhaled in the lungs
◦ Very pathogenic
◦ Known as Wool Sorters disease –
associated with livestock
◦ Organism is beta hemolytic with a
double zone of hemolysis
◦ Organism has a polyglutamic acid
capsule
◦ Organism produces at least three
toxins
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Destroy tissues and cells
Promotes growth of organism in
tissues
If it becomes systemic it can spread
through lymph
◦ Vaccination available but it is usually
not give to humans (just animals)
◦ PCN is drug of choice
Etiology Mycobacterium leprae
 Causative agent related to TB
 Development of multiple lesions on
skin
 Loss of sensory perception in areas
of skin that have been infected
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Areas that are cooler than body
temperature
Fingers
Toes
Nose
Elbows
Ears
Organism doesn’t actually damage
but the body’s cell mediated
response destroys the nerve endings
(pacinian corpuscles)
Organism is acid fast
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The average generation period is
about 12-14 days. 1 cell
becomes 2 during this period.
Pretty slow growing bug.
Incubation period is 12 weeks to
40 years! With a mean of two
years
BCG – vaccine for TB,
preventative for leprosy
Not very common
Tx - topical steroids can be used
to control swelling.
Dapsone used for treatment.
Severe disease caused by a toxin
made by S. aureus or S. pyogenes,
characterized by shock and multiple
organ dysfunction.
◦ Signs and Symptoms:
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High fever, sometimes accompanied
by chills
Profound malaise
Nausea, vomiting and/or diarrhea
Diffuse red rash resembling a
sunburn
Rash followed in 1 or 2 weeks by
peeling of the skin, particularly the
skin of the palms or soles
Redness of eyes, mouth, throat
Confusion, seizures, headaches
Myalgias (muscle aches)
Hypotension (low blood pressure)
Organ failure (usually kidneys and
liver)
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Causative agent: S. pyogenes
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Childhood disease famous in
1800s
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Begins as pharyngitis, organism
begins to produce toxin
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Symptoms:
◦ Pinkinsh-red rash covers the whole
body except palms of hands and
soles of feet
◦ Rash is the body’s rxn to the
circulating toxin
◦ Tongue has spotted, strawberry
appearance and the upper
membrane is lost. Red and large
Bacterial conjunctivitis due to the
common pyogenic (pus-producing)
bacteria causes marked
grittiness/irritation and a stringy,
opaque, grey or yellowish
mucopurulent discharge (gowl, goop,
"gunk", "eye crust") that may cause
the lids to stick together (matting),
especially after sleeping.
Common etiologies: S. aureus and C.
trachomatis
Bacterial Neonatal Gonorrheal
Opthalmia: serious form of
conjunctivitis
 Symptoms: Acute infection
with much pus formation
 At more advanced stages
ulcers form on cornea
 infection carries high risk of
blindness
 Causative Agent: Neisseria
gonorrhoeae
 Transmission: acquired as
infant passes through the
birth canal
 Rx: oral Tetracycline or
Erythromycin drops for
prevention
Keratitis is a condition in which the eye's
cornea, the front part of the eye, becomes
inflamed. The condition is often marked by
moderate to intense pain and usually
involves impaired eyesight.
Herpetic Keratitis: Herpes simplex
keratitis is a serious viral infection. It
may have recurrences that are triggered
by stress, exposure to sunlight, or any
condition, disease or treatment which
impairs the immune system.
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Symptoms:
 eye pain
 Impaired vision
 Eye redness
 White patch on the cornea
 Sensitivity to light
 Increased tearing
Causative Agent: Herpes simplex 1 (cold
sores)
Transmission: problem for contact lens
wearers especially
Frequently results in severe
eye damage
Symptoms:
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eye pain
Impaired vision
Eye redness
White patch on the cornea
Sensitivity to light
Increased tearing
Transmission: contact lenses
Tx: Topical ointment
(propamidine or miconazole),
corneal transplant or eye
removal may be required