BMS 501 Skin and Eye infections

Perspiration protective factors

Low pH and high salt concentration

Lysozyme in perspiration and tears break down peptidoglycan

Bacteria present in oily skin type

Staphylococcus

Bacteria present in dry skin type

Pseudomonas

Primary lesions

Directly associated with a disease and can be used to diagnose an infection

Secondary lesions

Less strictly defined, can be from multiple sources and may indicate healing or complications from primary lesions.

Rash

A widespread eruption of lesions

Plantar and Seed wart

Warts on feet and hands

Herpes viruses

Large DNA virus with spike

Have latent periods during the life long infection

8 types cause human disease

Varicella-zoster virus

Chickenpox

Typically Causes mild childhood disease

How is Varicella transmitted

respiratory route, skin contact with lesions

Is there a vaccine for varicella?

Yes, varivax

Shingles

Latent varicella infection becomes reactivated later in life due to stress or decline in the immune system

Results in very painful lesions

Is there a vaccine for shingles?

Yes, zostavax taken when >50

Smallpox

Variola major virus. 30% mortality rate and highly contagious.

Eradication of smallpox

Only infectious disease to ever be eradicated, world wide eradication by 1980

Vaccine is no longer routinely administered

Mpox

similar to smallpox, but milder symptoms.

Mpox transmission

skin to skin via rash, scabs, body fluids. Also in utero.

Is there a vaccine for Mpox?

Yes, there are two

Human Herpes virus 1

Cold sores, fever blisters, painful, itchy vesicles (contagious) that crust and heal

Herpes simplex viruses

HHV-1 and HHV-2 (genital herpes)

Herpetic labialis

oral herpes

Herpetic whitlow

fingers

Herpetic gladiatorum

wrestlers herpes

Hermetic keratitis

ulceration of the cornea

Hermetic encephalitis

Highly fatal due to inflammation of the brain

measles causative agent

Rubeola virus (enveloped)

Why are measles reemerging

Lack of a vaccine

How is rubeola tranmitted

Respiratory route, contagious prior to symptoms

Rubeola symptoms

Cold symptoms after about 10-12 days with kopliks spots along gum line

red, maculopapular rash on the face first (around day 14)

Is there a vaccine for rubeola?

Yes, MMR given above 12 months with boosters

rubella (German measles)

Rubella virus (enveloped)

Milder than rubeola

Severe fetal damage in pregnancy because it crosses the placenta

Transmission route of rubella

Respiratory route

Is there a vaccine for rubella

Yes, MMR

Erythema infectious: fifth disease

Caused by parvovirus B19-non enveloped

Erythema infectiosum symptoms

”slapped cheek” facial rash

Flu like symptoms

Roseola

HHV-6 and HHV-7

Common mild childhood disease with a sudden high fever and rash on neck and back once fever suddenly ends

How is roseola transmitted

respiratory route

Hand, footy and mouth disease (HFMD) causative agents and age

Coxsackievirus A16

Enterovirus 71

Children most common

HFMD signs and symptoms

Blister-like sores on the mouth, lesions on the hands and feet

Warts

papillomaviruses

HPV-1-4

Uncontrolled benign broth of skin

Transmitted person to person

Treatment by removal

Folliculitis

S. Aureus, S. Epidermidis

Staphylococcal scaled skin syndrome

S. Aureus

Impetigo

S. Aureus, S. Pyogenes

Necrotizing fasciitis

s. Pyogenes

Acne

P. Acnes

Cutaneous anthrax

B. Anthracis

Gas gangrene

C. Perfringens

Leading cause of skin diseases

Staphylococcus species

S. Aureus virulence factors

Coagulase

Catalase

Enzymes that break down clots

Pyrogenic toxin

Exfoliative toxin

Hyaluonidase

Hemolysins

Lipases

Impetigo

Caused by S. Aureus

Newborns 2-5 y/o

Superficial blisters tyI ally oozing yellowish fluid with yellowish/brown flaky crust

Erysipelas

S. Aureus infection if impetigo spreads to surrounding skin and lymph nodes

Charactorized by excessive inflammation and pain, fever, chills

Cellulitis

S. Aureus infection that reaches the lower dermis and subcutaneous fat. Charactorized by red, swollen, painful skin. Fever, legs most commonly infected

Folliculitis

Minor infection at the base of a hair follicle by S. Aureus

Furuncle

S. Aureus boil-painful abscess full of pus in the region of a hair follicle

Methicillin resistant staphylococcus aureus

Most S. Aureus are methicillin resistant now

Scalded skin syndrome

S. Aureus, separation of dermis from epidermis

Exfoliative toxin is secreted into bloodstream to skin

Peeling of epidermis

Children and elderly

Toxic shock syndrome

S. Aureus secreting TSS toxin, happens during menstruation, surgery, and tattooing

Also caused by S. Pyogenes

TSS toxin MOA

causes overstimulation of immune system resulting in a high fever, vomiting, diarrhea, sore throat, severe sore muscles, skin peeling, shock and heart failure.

Streptococcus Pyogenes

can cause some of the same infections as S. Aureus

Beads on a string appearance

pus forming (pyogenes)

S. Pyogenes virulence factors

Capsule and M protein on cell surface

Antiphagocytic

Produces numerous toxins

erysipelas

cellulitis of the dermal layer caused by S. Pyogenes or S. Aureus

Necrotizing fasciitis

”flesh-eating disease”

caused by S. Pyogenes

Exotoxin A

Bacteria enter through wound or trauma

Streptococcal toxic shock syndrome

Large flat rash over several areas of the body

Similar to S. Aureus toxic shock syndrome

P. Aeruginosa

Found in soil and water

Contain Pili slime layer

Endotoxin and exotoxins

Opportunistic

What does P. Aeruginosa often infect

Burn victims producing a blue-green pus in burn wounds

Gas gangrene

Clostridium perfringens grows deep in wounds, endosperm forming

Can block blood flow resulting in tissue death

Can lead to bacteremia

Black skin

Cat scratch fever

Bartonella hensellae

Normal flora of cats and dogs, usually self limiting

Candidiasis

Opportunistic

Itchy, hot, painful

Skin, mouth and GU tract

Dermatomycoses

Fungal disease of hair, skin or nails

Tinea capitis

ringworm of the scalp

Tinea cruris

Jock itch

Tinea pedis

Athlete’s foot

Tinea unguium

Nails

Conjunctivitis

Infection of conjunctiva

Most common cause is haemophilus influenza

Highly contageous

Keratitis

Inflammation of the cornea

Protective layers of the cornea are destroyed

More serious than conjunctivitis

Can be caused by HHV-1

Differences between bacterial and viral conjunctivitis

Viral is red and watery

Bacterial has pus discharge and eyes may feel stuck shut

Blepharitis

Inflammation of eyelid margin typically caused by S. Aureus

Accompanied by burning sensation

Trachoma

Caused by chlamydia trachomatis

Eyelid turns inward so that eyelashes scratch and perminately damage cornea

Neonatal conjunctivitis/opthalmia

Transmitted to infant in birth canal

appears 2-5 days after birth with copious pus formation

Most hospitals are required to put antibiotics in newborns eyes