Infections and Infestations of the Skin Flashcards
What is panton valentine leukocidin?
- It is a beta-pore forming toxin released by Staphylococcus aureus
- Increased morbidity, mortality, trasmissability
- Painful, multi-site, recurrent, present in contacts
What are the extracutaneous presentations of panton valentine leukocidin (3)?
- Necrotising fasciitis
- Necrotising pneumonia
- Purpura fulminans
What is the presentation?
- Purpura fulminans
What is the presentation?
- Necrotising fasciitis
A patient presents with the following symptoms:
What is the most likely diagnosis?
- Panton valentine leukocidin releasing staphylococcus aureus
What are the risks of acquiring panton valentine leukocidin releasing staphylococcus aureus (5Cs)?
- Close contact
- Contaminated items
- Crowding
- Cleanliness
- Cuts
How is panton valentine leukocidin releasing staphylococcus aureus managed (4)?
- Abx
- Nasal ointment
- Chlorhexidine body wash
- Treat contacts
What is the presentation?
- Folliculitis (follicular erythema; sometimes pustular)
May be infectious or non-infectious (in HIV)
A patient presents with the following symptoms:
What is the most likely diagnosis?
- May be infectious (Staphylococcus aureus, particularly strains expressing panton valentine leukocidin (PVL))
OR
- Non-infectious (in HIV)
How is folliculitis managed?
- Antibiotics (usually flucloxacillin or erythromycin)
- Incision and drainage is required for furunculosis
What is the presentation?
What is the cause?
- Pseudomonal folliculitis
- Staphylococcus aureus from hot tub, swimming pool, depilatories, wet suits
What is a furuncle?
- A furuncle is a deep follicular abscess involving one follicle
What is a carbuncle?
- A carbuncle is a deep follicular abscess involving several adjacent follicles
More likely to lead to complications such as cellulitis and septicaemia than a furuncle
What is the presentation?
- Cellulitis
What is the cause of cellulitis (2)?
- Streptococcus pyogenes
- Staphylococcus aureus
How is cellulitis managed (1)?
- Systemic antibiotics
What is the presentation?
-
Impetigo
- Superficial bacterial infection, stuck-on, honey-coloured crusts overlying an erosion
What is the cause of impetigo?
- Streptococci (non-bullous)
- Staphylococci (bullous)
Impetiginisation: occurs in atopic dermatitis-> superimposed infection -> gold crusting
How is impetigo managed (1)?
- Topical +/- systemic antibiotics
What is the presentation?
-
Ecthyma
- Severe form of streptococcal impetigo
- Thick crust overlying a ‘punch out’ ulceration surrounded by erythema
- Usually on lower extremities
What is the presentation?
- Erysipelas
What is erysipelas?
- Infection of upper dermis and subcutis caused by β-haemolytic streptococci or Staphylococcus aureus
Presents as erythematous indurated plaque with a sharply demarcated border and a cliff-drop edge (+/- blistering)
How is erysipelas managed (1)?
- IV antibiotics
What is the presentation?
What is the cause?
-
Erythasma
- Well demarcated patches in intertriginous areas
- Corynebacterium
What is the presentation?
What is the cause?
-
Pitted Keratolysis
- Pitted erosions of sole of foot
- Treated with topical clindamycin
- Corynebacterium
A patient presents with the following symptoms:
What is the diagnosis?
- Staphylococcal Scalded Skin Syndrome (SSSS) due to exfoliative toxin
Neonates, infants or immunocompromised adults (In neonates, kidneys are immature so cannot excrete the exfoliative toxin quickly)
A patient presents with the following symptoms:
* Fever > 38.9oC
* Hypotension
* Diffuse erythema
* Involvement of ≥ systems: GI, CNS, renal, hepatic, muscular
* Mucous membranes (erythema)
* Hematologic (platelets < 100 000/mm3)
What is the diagnosis?
- Toxic shock syndrome due to Group A Staphylococcus aureus strain that produces pyrogenic exotoxin TSST-1
What is the presentation?
-
Necrotising fascitis
- Initial dusky induration (usually of a limb), followed by rapid painful necrosis of skin, connective tissue and muscle.
What is the cause of necrotising fascitis?
- Usually synergistic: streptococci, staphylococci, enterobacteriacee and anaerobes > Blood and tissue cultures can determine organisms and sensitivities.
A patient presents with the following symptoms:
What is the diagnosis?
-
Erysipeloid
- Erythema and edema from contaminated raw fish or meat =› slow spread
A patient presents with the following symptoms:
What is the diagnosis?
-
Anthrax
- Painless necrotic ulcer + oedema + lymphadenopathy
A patient presents with the following symptoms:
What is the diagnosis?
-
Blistering distal dactylitis
- Staph or strep
- Young children; 1+ superficial bullae on erythematous base
Volar fat pad of finger
A patient presents with the following symptoms:
What is the diagnosis?
-
Lyme disease
- Annular erythema from infected tick bite
Borreliosis; 1-30 days from infection
* Neuroborreliosis
* Arthritis
* Carditis
A patient presents with the following symptoms:
What is the diagnosis?
-
Tularaemia
- Infected bite (rodents, rabbits, hares)
Ulceroglandular form
Painful ulceration
What are the different presentations of herpes simplex virus (HSV) (4)?
- Oral lesions: cold sores
- Genital lesions
- Herpetic whitlow
- Eczema herpeticum
How is herpes simplex virus (HSV) diagnosed?
- Swab for polymerase chain reaction
How is herpes simplex virus (HSV) managed (2)?
- Oral valacyclovir or acyclovir 200mg five times daily in immunocompetent localised infection
- Intravenous 10mg/kg TDS X 7-19 days if severe, systemic or at risk
A patient presents with the following symptoms:
What is the diagnosis?
- Oral lesion caused by herpes simplex virus (HSV-1)
HSV-1 is mainly transmitted by oral-to-oral contact to cause oral herpes (which can include symptoms known as “cold sores”), but can also cause genital herpes. HSV-2 is a sexually transmitted infection that causes genital herpes. Both HSV-1 and HSV-2 infections are lifelong.
A patient presents with the following symptoms:
What is the diagnosis?
- Genital lesion caused by herpes simplex virus (HSV-1)
HSV-1 is mainly transmitted by oral-to-oral contact to cause oral herpes (which can include symptoms known as “cold sores”), but can also cause genital herpes. HSV-2 is a sexually transmitted infection that causes genital herpes. Both HSV-1 and HSV-2 infections are lifelong.
A patient presents with the following symptoms:
What is the diagnosis?
-
Eczema herpeticum
- Monomorphic, punched out erosions (excoriated vesicles)
It’s an emergency!
A patient presents with the following symptoms:
What is the diagnosis?
-
Herpetic whitlow
- HSV (1>2) infection of digits - pain, swelling and vesicles (vesicles may appear later)
Misdiagnosed as paronychia or dactylitis
Often in children
A patient presents with the following symptoms:
* Fever
* Malaise
What is the diagnosis?
-
Varicella zoster virus (VZV) (Chickenpox)
- Results in a characteristic skin rash: small, itchy blisters, which eventually scab over
Shingles: reactivation of virus
Dermatomal
* Single dermatome
* Multidermatomal
A patient presents with the following symptoms:
* Fever
* Malaise
* Sore throat
What is the diagnosis?
-
Hand-Foot-Mouth disease
- Organisms: Coxsackie A16, Echo 71
A patient presents with the following symptoms:
What is the diagnosis?
-
Morbilliform rashes / eruptions caused by:
- Measles (Most likely)
- Rubella
- EBV
- CMV
- HHV6
- HHV7
A patient presents with the following symptoms:
What is the diagnosis?
-
Wart
- > 200 subtypes of HPV
- Self- limiting: most go away by themselves no need TX
- Careful: immunocompromised
A patient presents with the following symptoms:
What is the diagnosis?
-
Orf
- Caused by parapoxvirus in direct exposure to sheep or goats
- Resolve without therapy
A patient presents with the following symptoms:
What is the diagnosis?
-
Molluscum contagiosum
- Poxvirus infection, common in children & immunocompromised
- Usually resolve spontaneously
- Treatment options - curettage, imiquimod, cidofovir
A patient presents with the following symptoms:
What is the diagnosis?
- Candidiasis (Candida Albicans)
A patient presents with the following symptoms:
What is the diagnosis?
-
Scabies caused by sarcoptes species:
- Female mates, burrows into epidermis, lays eggs and dies
A patient presents with the following symptoms:
What is the diagnosis?
- Lice
