Perspiration & sebum contain

nutrients

Salt inhibits

microbes- NOT FUNGI, FUNGI LOVES SALT

Lysozyme

hydrolyzes peptidoglycan

Fatty acids inibit

some pathogens

Antimicrobial peptides:

Defensins

Defensins-

Small peptide antibiotics made by human cells.

Normal Microbiota of the Skin

Gram-positive, salt-tolerant bacteria
*Staphylococci
*Micrococci
*Diphtheroids

Exanthem:

Skin rash arising from another focus of the infection.

Enanthem:

mucous membrane rash arising from another focus of the infection.

SKIN RASH arising from another focus point of the infection is

Exanthem

MUCOUS MEMBRANE RASH arising from another focus of the infection.

Enanthem

Staphylococcal skin infections:

Staphylococcus aureus-

Gram-positive cocci, COAGULASE-POSITIVE (causes clumping)

Staphylococcus aureus (bad news):

Is-

antibiotic resistant

Staphylococcus aureus

Leukocidin

Staphylococcus aureus resists

opsoniztion

Staphylococcus aureus survives in

phagolysosome

Staphylococcus aureus is

lysozyme resistant

Staphylococcus aureus is an

exfoliative toxin

Staphylococcus aureus is a

superantigen

Staphylococcal skin infections can cause:

* Folliculitis
* Sty
* Furuncle
* Carbuncle
* Impetigo

Folliculitis:

Infection of the hair follicles

Sty:

folliculitis of an eyelash

Furuncle:

abscess; pus surrounded by inflamed tissue

Carbuncle:

Inflammation of tissue under the skin

Impetigo:

crusting (nonbullous) sores, spread by autoinoculation.

Scalded Skin Syndrome:
can also cause-

* Toxic shock syndrome (TSS)
- Toxic shock syndrome toxin 1

* Scalded skin syndrome
- Bullous impetigo
- Impetigo of the newborn

Streptococcal skin infections:

can produce/cause-

* Streptococcus pyogenes
* Group A beta-hemolytic streptococci
* Hemolysins
* Hyaluronidase
* Streptolysins
* M proteins
- Exotoxin A

Streptococcal Toxic Shock Syndrome:

* M proteins
* Complex w/fibrinogen
* Binds to neutorphils
* Activates neutrophils
* Release of damaging enzymes
* Shock & organ damage

Infections by Pseudomonads:

* Pseudomonas aeruginosa
- Gram-negative, aerobic rod
- Pyocyanin produces a blue-green pus
* Pseudomonas dermatitis (cause)
- Otitis externa (swimmers ear)
- Post-burn infections
* (is) Opportunistic

Buruli Ulcer is caused by

Mycobacterium ulcerans

Buruli Ulcer is

deep, damaging ulcers

Buruli Ulcer

exceeds incidence of leprosy

Classifications of Acne:

* Comedonal (mild) acne
* Inflammatory (moderate) acne
* Nodular cystic (severe) acne

Comedonal is _________ acne.

mild

Inflammatory acne is _________ acne.

moderate

Nodular cystic acne is _________ acne.

severe

Treatment for nodular cystic acne

Isotretinoin

Viral diseases of the skin:

* Warts
* Small pox
* Monkeypox
* Chickenpox
* Shingles
* Cold sores
* Measles
* Rubella
* Fifth disease
* Roseola

Warts

Papillomaviruse

Warts:

Treatment-

* Removal
* Cryotherapy
* Electrodesiccation
* Salicylic acid
* Imiquimod (stimulates interferon production)
* Bleomycin

Poxviruses:

* Smallpox (variola)
* Monkeypox

Smallpox (variola)

* Smallpox virus (orthopoxvirus)
- Variola major
-Variola minor
* Eradicated by vaccination

Monkeypox

prevention by smallpox vaccination

Chickenpox

Varicella-zoster virus (human herpesvirus 3)

Chickenpox:

transmitted by

respiratory route

Chickenpox:

causes

pus-filled vesicles

Chickenpox virus may remain laten in

dorsal root ganglia (spinal nerve)

Chickenpox prevention:

live attenuated vaccine

Shingles is the

reactivation of latent HHV-3, releases viruses that move along peripheral nerves to skin.

Shingles prevention:

live attenuated vaccine

Shingles- treatment

Acyclovir may lesson symptoms

Herpes Simplex

Human herpesvirus 1 (HSV-1) and 2 (HSV-2)

Herpes Simplex causes

Cold sores and/or fever blisters (vesicles on lips)

HSV-1-

can remain latent in trigeminal nerve ganglia

Herpes Simplex- treatment

Acyclovir

Measles (Rubeola) is a

measles virus

Measles is transmitted by

respiratory route

Measles causes

macular rash & Koplik's spots

Measles is prevented due to

vaccinations

Rubella (German Measles)

Rubella virus

Rubella causes

Macular rash and fever & CONGENITAL RUBELLA SYNDROME which causes severe fetal damage

How to prevent Rubella

vaccination

Fifth Disease

also known as Erythemia infectiosum
- Human parvovirus B19 produces mild flulike symptoms & facial rash

Cutaneous Mycoses

* DERMATOMYCOSES
- Also known as tineas or ringworm
- Metabolize keratin

** Common in southwest where it is hot & dusty**

Cutaneous Mycoses:

Genera of fungi involved-

* Trichophyton: infects hair, skin & nails
* Epidermophyton: infects skin & nails
* Microsporum: infects hair & skin

Genera of fungi that infects the Hair & skin-

* Trichophyton & Microsporum

Genera of fungi that infects the skin & nails-

* Trichophyton & Epidermophyton

Microsporum infects

hair & skin

Trichophyton infects

hair, skin & nails

Epidermophyton infects

skin and nails

Cutaneous Mycoses:

Treatment

* Topical miconazole
* Topical allylamine

Subcutaneous Mycoses

is more serious than cutaneous mycoses

Subcutaneous Mycoses

* Sporotrichosis
- Sporothrix schenkii= enters punture wound
- Treated with potassium iodid (KI)

Candidiasis

* Candida albicans (yeast)

Candidiasis may result when

antibiotics suppress competing bacteria.
- Occurs in skin & mucous membranes of genitourinary tract & mouth.
- Thrush: an infection of mucous membranes of mouth

Candidiasis:

Treatment

fluconazole

Scabies:

Sarcoptes scabies burrows in the skin to lay eggs

Scabies treatment

Topical insecticides

Pediculosis (lice)

* Pediculus humanus capitis (head louse)
* P.h. corporis (body louse)
- Feed on blood
- Lay eggs (nits) on hair
- Treatment: topical insecticides

Bacterial Diseases of the Eye

* Conjunctivitis

Bacterial Diseases of the Eye

Conjunctivitis:

* inflammation of the conjunctiva
* also called pinkeye or red eye
* commonly caused by Haemophilus influenzae
* associated w/unsanitary contact lenses

Bacterial Diseases of the Eye

Ophthalmia neonatorum:

* Caused by Neisseria gonorrhoeae
* Transmitted to a newborn's eyes during labor
* Prevented by treating a newborn's eyes
with antibiotics

Bacterial Diseases of the Eye

Chlamydia trachomatis

Chlamydia trachomatis causes

inclusion conjunctivitis, or chlamydial conjunctivitis.

Chlamydia is transmitted to newborn's eyes during

passage through the birth canal

Chlamydia trachomatis is spread through

swimming pool water

Chalmydia is treated with

tetracycline

Chlamydia trachomatis causes

trachoma

Trachoma is the leading cause of

blindness worldwide

Chlamydia trachomatis infection causes permanent

scarring; scars abrade the cornea, leading to blindness

Other infectious diseases of the eye

Keratitis:

* Inflammation of the cornea
* Fusariuim & Aspergillus (Africa & Asia)

Other infectious diseases of the eye

Herpetic keratitis:

* caused by herpes simplex virus 1 (HSV-1)
* infects cornea & MAY CAUSE BLINDNESS

Other infectious diseases of the eye

Acanthamoeba keratitis

* transmitted via water
* Associated w/unsanitary contact lenses

Acanthamoeba keratitis is transmitted via

water

Acanthamoeba keratitis is associated with

unsanitary contact lenses