diseases of the skin diane hannon anatomy and physiology

Diseases of the Skin

Diane Hannon

Anatomy and Physiology

Bacterial Skin Infections

1. Folliculitis: Pimple, Sty, Abscess

2. Scalded Skin Syndrome

3. Scarlet Fever

4. Impetigo

5. Acne

6. Boils and Carbuncles

Bacterial Skin Infections Folliculitis

• Inflammation and infection of the hair follicle, can occur anywhere on skin

• “pimples” Almost always caused

by S. Aureus which is always on the skin.

Also called pustules.


• Sty = Infection at the base of the eyelid

• Treatment: warm moist compresses, daily cleansing


• Abscess: localized collection of pus in any tissue of the body

• Encapsulates- prevents the spread of bacteria into the blood, but prevents circulating antibiotics from reaching the abscess

• Must be lanced and drained.

Bacterial Skin Infection Scalded Skin Syndrome

• Caused by S. Aureus• Begins with a slight

reddened area around the mouth

• 24-48 hrs later see easily ruptured vesicles over the whole body

• Skin Peels• Heals in 7 –10 days• Can lead to septicemia:

infection of the blood = death.

Bacterial Skin Infection Boils and Carbuncles

• Inflammation of hair follicles and sebaceous glands.

• Carbuncles are composite boils caused by Staphylococcus aureus.

Bacterial Skin Infection Scarlet Fever

• Caused by Streptococcus pyogenes (also causes strep throat)

• Produces a red toxin that causes the scarlet rash.

Bacterial Skin Infection Impetigo

• Highly Contagious• Pyoderma (pus producing skin

infection)• Transmitted by hands, toys,

furniture, DAYCARE• Symptoms include pustules

that rupture, producing a yellow crust over the lesions

• Tmt: washing, antibiotic ointment

Bacterial Skin Infection Acne

• Affects 80% of teens and adults.

• Primarily caused by male sex hormones which increase the size of the sebaceous glands.

• Microorganisms feed on the sebum


• Cystic Acne• Plugged ducts become

inflamed and rupture.• Bacteria will infect

area and cause scarring.


• Blackheads• Mild form of acne• Hair follicles become

plugged with sebum and keratin.


Treatment:• Frequent cleansing of

skin.• Topical ointment• Tetracyline (controls

the bacterial infection)• Accutane (inhibits

sebum production)

MRSA• Methicillin-resistant Staphylococcus aureus:

resistant to antibiotics commonly used to treat Staph infections

• Appearing in healthy people who share personal items such as athletes and students

• 2005- MRSA deaths higher than those due to AIDS

• MRSA- humans have helped build resistance by: over-prescribing antibiotics, also in livestock (meat supply and groundwater)

• Symptoms: small, red bumps, can cause deep abscesses or become blood borne (rash over body, chills, headache, joint pain)

• TMT: Vancomycin (expensive), some bacteria are developing a resistance to this

• Prevention:

• do not share personal items

• frequent hand washing or hand sanitizer (, alcohol works as sanitizer)

• do not overuse antibiotics

Viral Skin Disease

1. Rubella

2. Rubeola

3. Chicken Pox and Shingles

4. Warts

5. Herpes Simplex

Viral Skin Disease Rubella

• Rubella = German Measles (3-day measles)

• Symptom: rash on trunk of body occurring 14-21 days after infection, fever, chills, joint pain

• Vaccine since 1969

Viral skin Infection Rubeola

• Rubeola = Measles• One of most serious

childhood diseases• Immunization since

1963, Koplik’s spots in mouth

• Fever, runny nose, rash

Viral Skin Infection Chicken Pox

• Caused by Varicella Zoster Virus.

• Highly contagious: 3 million + in US

• 10-21 days after exposure, small irregular rose-colored lesions develop

• Can be fatal: virus invades and damages cells that line the small blood vessels = clots. Also leads to pneumonia

• Vaccine since 1995

Viral Skin Infection Shingles

• Caused by Varicella Zoster Virus.

• Latent virus acquired during prior case of chicken pox.

• Virus hides in nerve cells

• Pain and prickling or the skin, mild itching to severe pain.

• Fever, headache, malaise

Viral Skin Infections Warts

• Warts = Papillomas• Caused by HPV Human Papilloma Virus

• Infection lasts a lifetime.• Common warts: on hands

and fingers, transmitted by fomites (inanimate objects) and scratching

• Disappear spontaneously

Plantar warts: sole of feet, grows inward, cauliflower-like appearance, pain with walking

-surgical removal

• Genital warts: one of most common STDs, highly contagious, causes a higher incidence of cervical cancer

Viral Skin Infections Herpes Simplex

• HSV-1: Cold sores / fever blisters.

• Virus localizes in in a cutaneous nerve.

• Blisters itch and sting.

• Herpes Simplex Type 2

-genital herpes

-can be sexually transmitted but not always, can get it from the lips

HSV-1 and HSV-2 cannot be separated clinically

Fungal InfectionsTinea: term used to identify a number of

highly contagious fungal infections of skin

• Athletes Foot

• Ringworm

• Candida

• Madura Foot

Fungal InfectionsAthletes Foot

• Tinea pedis• Dry, scaly lesions that

result from fluid filled lesions on sweaty feet.

• skin cracks and a secondary skin infection results in soggy areas between toes.

Fungal Skin InfectionsRingworm

• Highly Contagious• Infects:

– Body: Tinea corporis

– Groin: Tinea cruris

– Nails: Tinea unguium

– Scalp: Tinea capitis

– Beard: Tinea barbae

Jock itch

Tinea unguium

Tinea capitis

Fungal Infections Candidiasis

• Candida = yeast infection

• Thrush: milky patches of inflammation on oral mucous membranes

• Infants, diabetics, prolonged antibiotic users

Fungal Infections Madura Foot

• Occurs mainly in the tropics, enters body through breaks in skin.

• Causes massive enlargement of the foot

• Amputation may be necessary.

Cancers

• Basal Cell Carcinoma

• Squamous Cell Carcinoma

• Malignant Melanoma

Basal Cell Carcinoma

• Least malignant• Most common Skin

Cancer common in fair-skinned blondes

• Cells of Stratum Basale• Lesions occur on sun

exposed area of face• Shiny, dome shaped

nodules develop a central ulcer

• Full cure in 99% cases

Squamous Cell Carcinoma

• Arises from cells in stratum spinosum

• Scalp, ears, dorsum of hands, lower lip

• Less common, grows more rapidly, metastasizes to lymph if not removed

• Sun induced

• Cure rate good if tx early.

Malignant Melanoma

• Cancer of melanocytes• Only 5 % of skin cancer,

but rising, more common in men

• Develops wherever there is pigment

• Appears spreading brown / black patch

• Metastasizes rapidly to surrounding blood vessels and lymph.

• Survival = 80%

ABCD Rule for Recognizing Melanoma

A Asymmetry: 2 sides of mole do not match

B Border irregularity: borders not smooth but

indented.

C Color: pigmented spot contains areas of

different color.

D Diameter: spot larger than 6 mm

diseases of the skin diane hannon anatomy and physiology

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