Week 13 - Topic 1: Skin Infections Flashcards
A patient comes in with a skin rash. What are some important “contagious” questions to ask?
- Have you been exposed to anyone with a rash?
- Have you travelled to a community in an outbreak of contagious rashes?
A patient comes in with a skin rash. What are some “non-contagious” questions to ask?
- Have you gone hiking or camping recently?
- Do you have a history of skin illnesses
- Do you have allergies to foods/medications/other?
- Have you been using new soaps, laundry detergents, topical preparations, new clothes?
What are the 3 lines of attack on the skin?
1) Systemic infections via BBI or toxin-mediated
2) Direct extensions from fistulae or sinuses
3) Direct breaches (cuts, bruises, warts, ulcers, etc)
What diseases result to attacking the skin from systemic infections?
- Measles
- Scarlet fever
- Toxic shock syndrome
What procedure can attack the skin from direct extensions?
Draining abscess
What are macules?
Flat red lesions
How do macules form?
Microbes/toxin arrive on the skin (ex: from the blood vessel) and inflammation/redness is triggered from responding macrophages and neutrophiles (leukocytes)
What is a papule?
Raised red lesion
How does a papule form?
Formation of a macule + invasion of neighbouring tissue triggering more inflammation
What are vesicles?
Papules filled with fluid
What two viruses can cause vesicls?
Herpes simplex and varicela zoster
How does an ulcer form?
When there is a rupture of the epithelium (or the vesicle)
What is a papilloma?
It is the growth and proliferation of a microbe (introduced directly) in the epithelium
What causes a papilloma?
Warts from HPV
What is a granuloma?
A build-up of macrophages
Where do you find Pseudomonas folliculitis?
In the water –> think spas
What does Pseudomonas folliculitis produce on the skin?
Macules, papules and vesicles on the back
Begin as pruritic red macules and end as itchy papules and pustules
What additional precautions should you use on Hot Tub Folliculitis?
Contact
What is folliculitis?
Build of of MO in the hair shaft + inflammation
What is a sty?
Inflammation of the sebaceous gland that opens into a follicle of an eyelash
What is a furuncle?
A folliculitis with pus
What is a carbuncle?
A cluster of furuncles that produce deep seated pus
What usually causes infectious such as folliculitis, sty, etc?
Staph aureus
What bacteria causes acne?
Propionibacterium acnes or spp
What bacteria causes gas gangrene?
Clostridium perfingens
Why shouldn’t diabetics walk barefoot?
C perfingens is found in soil and could cause gas gangrene in their feet
What bacteria causes abscesses?
Staph aureus
Strep pyogenes
What bacteria causes impetigo?
Staph aureus
Strep pyogenes
What precautions does acne require?
Routine
What precautions does gas gangrene require?
Routine
What precautions does draining an abscess require?
Additional (Contact)
What precautions does impetigo require?
Additional (contact)
What bacteria causes leprosy?
Mycobacterium leprae
What is the incubation period of leprosy?
2-10 years
What precautions does leprosy require?
Routine
Additional (contact) only when it has been untreated
What is another name for Leprosy?
Hansen’s disease
What type of lesions do you find in leprosy and where are they?
Macules, patches, papules and nodules
Symmetrically distributed all over the body
True or False: People with leprosy lose their eyebrows and eyelashes.
True
Leprosy is easily treatable. If left untreated, what happens to the person?
Disfigurement and nerve damage
What animal is also a host for leprosy?
Armadillo
What bacteria causes Scarlet Fever?
Group A strep
What bacteria causes Necrotizing fasciitis?
Group A strep
What bacteria causes Erypsipela (St Antony’s fire)?
Group A strep
What precautions does Scarlet Fever require?
Routine
What precautions does necrotizing fasciitis require?
Additional (droplet + contact)
What bacteria causes Scalded skin syndrome?
Staph aureus (strain that produces TSST-1 and exfoliative toxin)
What bacteria causes impetigo of newborn (impetigo neonatorum)?
Staph aureus (strain that produces TSST-1 and exfoliative toxin)
What precautions does Scalded Skin Syndrome require?
Additional (contact)
What precautions does newborn impetigo require?
Additional (contact)
What type of gram and shape is Staph aureus?
Gram + cocci
True or False: Staph aureus is an opportunistic pathogen.
True
True or False: Streptococcus pyogenes is the common cause of nosocomial infections.
False, it is Staph aureus
What are the 3 virulence factors of Staph aureus?
1) Exotoxins
2) Exoenzymes
3) Structural defenses against phagocytosis (slime, protein A preventing opsonization)
What are the 2 categories of the exotoxins of Staph aureus?
1) Cytotoxins, exfoliative toxin –> toxic shock syndrome toxin-1 (TSST-1)
2) Enterotoxin and leukocidin –> food poisoning
What virus causes chickenpox?
Varicella zoster virus
What virus causes shingles?
Varicella zoster virus?
What precautions does chickenpox require?
Additional (airborne)
What precautions does shingles require?
Routine
What virus causes german measles?
Rubella virus
What precautions does German Measles require?
Droplet (for 7 days after onset of rash)
What virus causes Measles?
Rubeola virus
What precautions does measles require?
Airborne (for 4 days after start of rash)
What lesions are found in chicken pox?
Macules, papules and vesciles
How long is chicken pox contagious for?
2 days before onset of rash up until lesions dry up
What lesions are found in german measles?
Macules and papules
What lesions are found in measles?
Macules and papules
How long is a person with measles contagious for?
4 days before onset of rash up until 4 days after onset
What is the difference between german measles and measles in terms of symptoms?
German measles:
They do not look sick –> mild fever + palpable lymph nodes
Measles:
They look sick –> fever + cough + conjunctivitis + coryza + Koplic spots
What are koplic spots?
Small, red irregular shaped spots with blue-white centers on the mucosal layer of the oral cavity = Measles
What virus causes smallpox?
Variola virus
What precautions does smallpox require?
Airborne + contact (until all lesions have separated and crusted, 3-4 weeks)
What virus causes warts?
70 different types of HPV
What are the 3 types of warts?
1) Common warts
2) Venereal warts
3) Planter warts
True or False: All warts require additional precautions?
False, only planter warts requires contact precautions
What type of lesions are found in warts?
Papillomas
What type of fungus causes tinea (ringworm)?
Dermatophytes
What type of fungus causes diaper rash?
Candida
What precautions does tinea require?
According to Rpap: routine
According to Ramona: additional
What precautions does candida require?
Routine
What technique must you use when taking a wound sample?
Aseptic no touch clean technique
What are the steps in taking a wound sample?
1) Remove non-viable tissue (necrotic or eschar)
2) Irrigate to remove exudate and topical agents
3) Scrap the base or break the pustule
4) Moisten swab with NS
5) Rotate over 1-2 cm area w/pressure to express fluid or scrap deep within the wound
6) Place swab in transport media, biohazard bag, label and date
7) Do not refrigerate
True or False: For abcesses, you send in a swab.
False, you send pus or fluid
Where do you aspirate the pus/fluid from an abcess?
Into a sterile container, such as a syringe (send without needle)
Can you refrigerate abcess samples?
No
What are ectoparasites?
Parasites that live on their host (outer layer of skin) and depend on them for nourishment
What parasite causes Leishmaniasis?
Leishmania (a flagellated protozoan infecting via sand flies)
What characterizes Leishmaniasis?
Boils on the face
What parasite causes scabies?
Sacroptes sabiei (mites)
What characterizes scabies?
They dig tunnels onto the skin (red) and lay eggs there
What do scabies mites feed on?
Human blood
How is scabies transmitted?
- Closed person-to-person contact of long duration
- Shared clothing and bedding
- Sex
What is Norwegian scabies?
A severe form of scabies
Millions in crusted scabies that look like psoriasis
Which is the only parasite that can transmit infections?
Body lice
What parasite causes pubic lice?
Phthirus pubis (crab louse)
True or False: Humans are the only reservoir for pubic lice.
True
What is the difference between pubic lice and head lice?
Pubic:
- Phthirus pubis
- Shorter life span off host (1-2 days)
- Morphological differences
Head:
- Pediculosis capitis
- Longer life span off host (several days)
What parasite causes body lice?
Pediculus humanus corporis
What diseases can body lice transfer?
Epidemic typhus
Trench fever
Epidemic relapsing fever
Where does body lice lay eggs?
On clothing and move onto skin to feed
True or False: Body lice is only found on the body.
False, it is also found on mattresses, sheets and clothing
What parasite causes bed bugs?
Cimex lectularius/hemipterus
What do bed bugs feed on?
Blood of animals (humans) while they sleep
True or False: Adult bed bugs can live several days without blood.
False, several months
Where do bed bugs live?
Within 8 feet of where people sleep
What is dangerous about bed bugs?
Can cause excessive scratching from itching with can lead to secondary skin infection
How do you spot bed bugs?
Rusty coloured blood spots (from poop)
Pepper-like exoskeletons while molting
What education can you provide to your patient regarding the treatment and prevention of bed bugs?
- Avoid scratching the area
- Apply antiseptic creams or lotions
- Take an antihistamine for itching
- Spray the infested area with insecticide
How so you find head lice?
By looking for adults or eggs (nits)
How do you treat prophylactically a family for head/pubic lice?
- Use permethrin for skin (brand name: Nix or Kwellada)
- Follow product manufacturer instructions + remove nits with vinegar
- Re-treat after 1 week if no clinical improvement
What do you do with clothing/bedding infested with ectoparasites?
1) If worn in the last 3 days, wash in hot water 50° or dry cleaned OR
2) Place in plastic bags for 1 week
What do you do with mattresses, chair or car seats that have been infested with ectoparasites or come in contact with infected person?
Vacuum them
