Perspiration & Sebum contain
nutrients
salt inhibits
most microbes
Lysozyme hydrolyzes
peptidoglycan
fatty acids inhibit
some pathogens
Mucous Membranes:
- line body cavities (epithelial cells)
- are acidic
- have cilia
The outer portion of the skin (epidermis) contains:
keratin, a waterproof coating
Normal microbiota of the skin are gram(+) and salt tolerant:
- Staphylococci
- Micrococci
- Diptheroids
These anaerobes grow in hair follicles
Propionibacterium acnes
These aerobes grow on the skin surface
Corynebacterium xerosis
a yeast that grows on oily skin surfaces; cause of dandruff
Malassezia furfur
S. epidermidis
coagulase-negative
*the majority of skin microbiota*
S. aureus
coagulase-positive
S. aureus resistance:
- antibiotic-resistant
- lysozyme resistant
- resists opsonization (phagocytosis)
- leukocidin
- exfoliative toxin
- superantigen
S. aureus
Staph skin infections:
- folliculitis
- sty
- furuncle
- carbuncle
- impetigo
Folliculitis
- infections of the hair follicle
Sty
folliculitis of an eyelash
Furuncle
abscess
- pus surrounded by inflamed skin
Carbuncle
inflammation of the tissue under the skin
Impetigo
- crusting sores (nonbullous)
- spread by autoinoculation
Scalded Skin Syndrome (SSS)
- Bullous impetigo / Impetigo of a newborn
S. aureus
Toxic Shock Syndrome (TSS)
S. aureus
S. pyogenes
Group A beta-hemolytic streptococci
(GAS)
- S. pyogenes
- cause severe & rapid tissue destruction
S. pyogenes (GAS)
- hemolysins
- hyaluronidase
- streptolysins
- M proteins
Streptococcal TSS
SHOCK & ORGAN DAMAGE
Diseases caused by P. aeruginosa
- Otitis externa
- dermatitis
- burn infections
- respiratory infections
P. aeruginosa produces Pyocyanin
produces a blue-green pus
Buruli ulcer
Mycobacterium ulcerans
Buruli ulcer symptoms
- deep damaging ulcers
- exceeds incidence of leprosy
Viral disease of the skin:
- Warts
- Smallpox
- Monkeypox
- Chickenpox
- Shingles
- Herpes Simplex
- Measles (Rubeola)
- 5th Disease (Erythema Infectiosum)
- Roseola
Warts
Papillomaviruses
Treatment for Warts
Removal by:
- Cryotherapy
- Electrodessication
- Salicylic acid
Imiquimod, Bleomycin
Smallpox (variola)
orthopox virus
- erradicated by vaccination
Smallpox (variola) major ____% mortality
20% mortality
Smallpox (variola) minor ____% mortality
1% mortality
Chickenpox (varicella)
Varicella-zoster virus (HHV-3)
Chickenpox is transmitted
via respiratory route
Chickpox causes
pus filled vesicles
Chickenpox virus can lay dormant in
the dorsal root ganglia
The zoster-herpes virus, that affects the cutaneous sensory nerves
shingles
vaccine given to people who have been vaccinated for Chickenpox
Breakthrough varicella
Vaccination for Chickenpox
live attenuated vaccine
Herpes Simplex (HSV-1)
- oral & respiratory routes
- cold sores
- fever blisters
HSV-1: Herpes gladiatorum
vesicles on skin
HSV-1: Herpes whitlow
vesicles on fingers
HSV-2: Herpes encephalitis
- 70% fatality
- treatment - Acyclovir
HSV-1 remains dormant
trigeminal nerve
(facial nerve)
HSV-2 remains dormant in
sacral nerve ganglia
Measles (Rubeola)
- Measles virus
- transmitted via respiratory route
A rare complication of Measles:
Subacute Sclerosing PanEncephalitis (SSPE)
- 1 in 1,000,000 cases
Fifth Disease (Erythema Infectiosum)
HPV B19
- mild flu-like symptoms
- facial rash
List of skin rashes Fifth Disease derived from:
- Measles
- Scarlet Fever
- Rubella
- Filatov Dukes Disease
Roseola
HHV-6 & HHV-7
- fever, rash
- lasts 1-2 days
Cutaneous Mycoses
(ringworm, tineas)
Dermatomycoses
fungi that grow on keratin
Genera of cutaneous mycoses
- Trichophyton
- Microsporum
- Epidermophyton
Trichophyton
- hair
- skin
- nails
Microsporum
- hair
- skin
Epidermophyton
- skin
- nails
Treatment for cutaneous mycoses
- Miconazole
- Allylamine
Subcutaneous mycoses
Sporotrichosis
sporothrix schenchii
a fungus that penetrates the skin thru a wound
sporotrichosis
Sporotrichosis is treated with
potassium iodide (KI)
Candidiasis
candida albicans (yeast)
Candidasis occurs in
skin/ mucous membranes of GU tract & mouth
a yeast infection of the mucous in mouth
Thrush
Treatments for Candidasis
- Miconazole
- Nystatin
Systemic Candidasis is called
Fulminating Disease
Systemic Candidasis can be treated with
Fluconazole
Scabies
(Sarcoptes scabei)
- burrow in skin to lay eggs
Treatment for Scabies
topical insecticides
Pediculosis humanus capitas
head lice
Pediculosis humanus corporis
body lice
Pediculosis feed on
blood
Treatment for Pediculosis
topical insecticides
Diseases of the Eye:
- Conjunctivitis
- Ophthalmia neonatorum
- Chlamydia trachomatis
Conjunctivitis (pinkeye)
H. influenza
- unsanitary contact lens
Ophthalmia neonatorum
N. gonorrhoeae
- transmitted to baby's eye during birth
- treated with antibiotics at birth
Inclusion conjunctivitis (Chlamydia conjunctivitis)
Chlamydia trachomatis
- transmitted to baby's eye during birth
- spread thru swimming water
Treatment for conjunctivitis
Tetracycline
Trachoma
Chlamydia trachomatis
- causes permanent scarring of cornea
leading cause of worldwide blindness
Trachoma
What are the 2 bacterial Diseases of the eye that are transmitted to a newborn's eye during passage of the birth canal
- Ophthalmia neonatorum
- Chlamydia Conjuntivitis (inclusion)