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