Skin infections Flashcards
In which climates are skin conditions most prevalent?
Hot + humid
What sort of infection is caused by tricophytum rubrum? Where do they grow?
Tinea
Grow in keratin (skin, nails + hair)
What sort of pathogen is trycophytum rubrum?
Fungus
Give 3 examples of tinea infections
Tinea capitis
Tinea pedis
Tinea manu
Which pathogen is responsible for causing scabies?
Sarcoptes scabei
Recall the pathophysiology of a scabies infection
Sarcoptes scabei burrows into the stratum corneum to cause a Type IV DHT reaction
Give 3 common sites for scabies burrows
Groin
Axilla
Anticubital fossae
Recall the main symptom of a scabies infection and how long the latent period is before symptoms are seen
Widespread erythrematous rash
4 week latent period
What classification of bacterium is S aureus?
Gram positive
Recall the 4 toxins produced by S aureus
PVL (Causes necrotising abscess)
Exfoliative toxin (causes blisters)
TSS1
Enterotoxin
Recall 3 consequences of S aureus infection
Skin infection
Severe pneumonia
Sepsis
What is impetigo? Recall the appearance of imeptigo
An S aureus infection of the subcorneal layer of the epidermis
Yellowish with golden crust
What are 5 possible manifestations of S. Aureus Skin Infections? Describe what is infected in each
Impetigo (sub corneal layer of epidermis)
Folliculitis (mouth of hair follicle)
Ecthyma (full thickness of epidermis)
Boil (abscess of hair follicle)
Carbuncle (abscess of several adjacent hair follicles)
What does ecythema look like?
Crusted thick lesion
Necrotic at surface
Which group of the population are susceptible to Staphlococcal Scalded skin Syndrome?
Children < 5 years old
Exfoliative toxin causes outer layers of skin to blister + peel
What does exfoliative toxin production by S aureus result in?
Bullous impetigo
Splitting of skin at higher levels of the epidermis
What sort of pathogen is treponema pallidum? What does infection by this cause? What is the main way in which this is transmitted?
Gram negative bacterium
Syphilis
STD
Recall the duration of each of the phases of syphillis infection
Primary = 3-8 weeks Secondary = 6-12 weeks Tertiary = years later
Recall the main symptoms of the primary phase of syphillis
Painless ulcer at inoculation site
Recall the symptoms of secondary syphillis
Disseminated infection
Generalised rash, lymphadenopathy + flu-like illness
Describe the rash of secondary syphilis. Which areas are commonly effected?
Maculopapular
Erythrematous
Palms + soles
Which body systems are affected by tertiary syphillis?
Skin, neurological + vascular
What is the first-line treatment for congenital syphillis?
Penicillin
Recall which serotypes of HHV are known as EBV, VZV and CMV
VZV = HHV3 EBV = HHV4 CMV = HHV5
Recall which types of HSV cause oral and genital herpes
Oral = type 1 Genital = type 2
Which cells are infected in an HSV infection? What is the consequence of this?
Neurons
HSV 1 + 2 + VZV have latency, can be reactivated in times of stress
Which pathogen commonly infects at defective skin barriers due to eczema?
Herpes simplex virus
Leads to eczema herpeticum
What disease is produced by herpes spreading to the brain?
Herpes encephalitis
Which serotype of HHV is associated with Kaposi’s sarcoma?
HHV8
Where does VZV have latency?
Dorsal root ganglia
What are the possible severe consequences of reactivation of VZV (Herpes Zoster)?
When CNV is infected you get face involvement so acyclovir is given IV rather than orally so as to avoid blindess
What is the clinical presentation of herpes simplex virus? How long does this presentation usually last?
Vesicular rash
2 weeks
Describe the presentation of varicella zoster virus
“chickenpox”- vesicular rash
Maiaise
Fever
Sore throat
Risks of what are increased by developing chickenpox as an adult?
Encephalitis
Pneumonia
Where do candida yeasts grow?
Warm wet surfaces e.g. body folds
