LAYERS OF SKIN

• Epidermis - 5 layers formed by mitosis
• Dermis - Papillary Layer & Reticular Layer -- VITAL
• Hypodermis - Loose connective adipose

BACTERIAL INFECTIONS

• Abcesses - Localized collection of pus - superficial pustules, pimples, furuncles, boils, carbuncles, pyogenic groups of hair follicles, deep skin abcesses
• Spreading Infections - Can be limited to epidermis or can involve subcutaneous fat
• Necrotizing Infections - Death of infected tissue - flesh eating bacteria

STAPHLOCOCCAL INFECTIONS

-bacterial -

-Staph-

• Most common bacterial skin infections
• Part of normal flora
• Do not cause harm unless there is a break in skin

FURUNCLES (BOILS)

-bacterial -

-Staph-

• Causitive Agent - Staphloccus aureus
• Hot Tub exposure to Pseudomonas Aeruginosa & Pseudomonas Folliculitis
• Occure in hair follicles - face, neck, butt, thighs, armpit

CELLULITIS

-bacterial -

-Staph-

• Acute infection of dermis / subcutaneous
• Caused by S. Aureus, Streptcocci
• Redness, swelling, warmth,pain, tenderness
• Systemic anitbiotics, cold compress, analgesics are needed
• Most common - lower legs, arms, hands

IMPETIGO (PYODERMA)

-bacterial -

-Staph-

• Superficial infection limited to epidermis
• Common in kids, but not limited
• Cause: S. aureus and group B. streptocci in children
• Passed via contact sports and vectors
• Treatment: Topical, oral antibiotics, hygiene

STREPTOCOCCAL INFECTIONS

• Usually secondary infection
• Glomerulonephritis can occur due to antibiotic treatment

ERYSIPELAS

-bacterial-

-strep-

• Acute Infection
• Caused by Group A Strep
• Used to only infect face, but now affects legs as well
• Breakouts have raised edge and sharp borders

ACUTE NECROTIZING FASCIITIS

-bacterial-

strep

• Flesh eating bacteria
• Uncommon infection in deeper tissue
• Aerobic and Anerobic bacteria present
• Necrosis due to virulent strain of S. Pyogenes (GRAM POSITIVE GROUP A STREP)

ACNE

-bacterial-

strep

• Cause: Propionibacterium acnes
• Lives in fatty acids secreted by sebacous glands - skin oil
• Adolescents mostly effected
• Tetracycline-resistant P. acnes becoming common

LEPROSY

-bacterial-

strep

• HANSONS DISEASE
• Mycobacterium leprae
• Infected many but now limited throughout the world
• Not very contagious
• Skin, mucus membrane, nerves
• Overcrowding and poor hygiene thought to be the cause

VIRAL INFECTIONS

• Most common cause of acute infections not requiring hospitalizations
• Some via skin, some via insect bite
• Few via animal bite, needles, transfusion, acupuncture
• Some viruses can enter via resp tract and infect skin - measles, rubella, chicken-pox

WARTS

-viral-

• Caused by HPV
• Mostly on hands and feet
• Direct Contact, Fomites, Autoinoculation
• Treatment - Salicyic and lactic acid, freezing with nitrogen, electrodesiccation, laser surgery

HERPES SIMPLEX

-virus-

• Painful watery blisters
• Skin, mucous membranes, lips, genitals
• HSV1-Fever blister on lips and mouth
• HSV2 - Genital herpes
• Can remain dormant and activate with uv, xray,heat, cold, stress, hormones
• Treatments reduce duration - CAN NOT BE CURED

VARICELLA-ZOSTER

-virus-

• Form of herpes
• Manifest as chicken pox
• When contracted later in life, get herpes zoster "SHINGLES"
• Transmission: Resp droplets or secretions
• Can be latent and reactivate replicating along neural pathways causing rash along dermatome

MOLLUSCUM CONTAGIOSUM

-virus-

• Caused by POXVIRUS
• Raised pearl like papules or nodules on skin
• More common in children
• Contagious and spread via direct contact including fomites and sexual contact
• Can NOT infect palms or soles of feet

ROSEOLA INFANTUM

-virus-

• SIXTHS DISEASE
• HHV-6 HHV-7 self limiting disease in children 6m-2y
• High grade fever 102-104 for 3-5 days followed by a skin rash starting on trunk spreading to limbs

SMALLPOX

-virus-

• Acute contagious disease
• Caused by VARILA VIRUS which is part of ORTHOPOXVIRUS family
• One of the most devastating diseases of all time
• Transmit: person to person via contact with skin lesions or secretions of resp tract
• 1967 WHO eradicated smallpox with vaccine from Edward Jenner. By 1979 smallpox was nearly gone

FUNGAL INFECTIONS

• Classified as Mycoses and are generally parasites that can present mild infections. When the immune system is compromised however, fungal infections can be very serious!!
• Live off living or dead organic matter
• Many fungi live on damp surfaces - public showers and locker rooms

TINEAS

-fungal-

• RINGWORM
• Superficial infection affecting skin, nails and hair
• Named on body part infected
• Live off dead epidermis for food
• DERMATOPHYTES most common form

TINEA CAPITIS

-fungal-

• Infection of the scalp - CRADLE CAP
• Bald patches due to destruction of hail follicles
• Common in school aged children
• Microsporum Canis - from cats and dogs
• Trichophyton Tonsurans - from humans
• Oral anti fungals for treatment

TINEA CORPORIS

fungal

• Can affect the body anywhere
• Contagious by shower mats, walls, pools
• Can present symptoms of ringworm and burning

TINEA VERSICOLOR

-fungal-

• Is NOT contagious
• Comes in form on yeast rather than fungal
• Caused by Malassezia furfur / pityrosporum ovale
• Skin may be uneven in color for several weeks

TINEA CRURIS

-fungal-

• JOCK ITCH
• Mainly in men
• Caused by friction of clothing, moisture, sweat
• Transmitted: Skin to skin contact or jock strap

TINEA UNGUIUM

-fungal-

• Called ONYCHOMYCOSIS
• Infects mostly toenails
• Can be caused by untreated fungal infections
• At risk: Diabetes, peripheral vascular disease, artificial nails, close fitting rubber foot wear, older women
• Difficult to cure and may return

TINEA PEDIS

-fungal-

• ATHLETES FOOT
• Thrives in warm, humid enviornments
• Caused by TRICHOPHYTON RUBRUM
• Most common of tinea infections
• Contagious - direct contact or fomites

CUTANEOUS CANDIDIASIS

-fungal-

• Caused by yeast (Candida albicans - common form of diaper rash)
• Normal flora- oral, genital and large intestine
• Infectious when immunocompromised
• Diabetes, obesity, antibiotics and rubber gloves cause increased risk

SUBCUTANEOUS MYCOSES

• Fungal disease that penetrates dermis or deeper layers after trauma
• Mainly in the tropics

CHROMOBLASTOMYCOSES

-sub-q fungal-

• Limited mostly to subcutaneous tissue
• Localized fungal infections
• Mainly in lower extremities
• Bone, muscle and tendon often involved
• Often caused by thorns and splinters
• Antibiotics may cause secondary bacterial infections

MYCETOMAS

-sub-q fungal-

• Chronic infection
• Occurs at site of injury and gets into deeper tissue
• Presents as subcutaneous nodule
• May be caused by actinomycetes which are bacteria that form filaments
• Found in soik and plants in tropics
• Often associated with injuries of feet
• May require amputation

SPOROTRICHOSIS

-sub-q fungal-

• Caused by SPOROTHRIX SCHENCKII
• Soil, plant material
• Thorns, barbs, pine needles
• Noncontagious - presents as painless bumps resembling insect bite