Skin Infections Flashcards
What percentage of GP appointments are skin related?
15%
25% are skin infections
Where are skin conditions more common?
Hot, humid climates amongst the poor
Describe Staphylococcus aureus
Gram positive
Commensal in 30% of humans
Colonisation in nose, axilla and groin.
What is the most common bacterial cause of skin infections?
Staphylococcus aureus
Name some skin infections caused by S.aureus
Impetigo
Folliculitis
Boils
Carbuncles
Give an example of a disease caused by S.aureus via the production of toxins
Staphylococcal scalded skin syndrome
Describe Treponema palladium and the disease it causes
Gram negative spirochaete Causes syphilis (usually an STI)
Outline the stages of Syphilis and their respective symptoms
- Primary- painless ulcers (chancre) at site of inoculation
- Secondary- maculopapular rash and lymphadenopathy
- Latent- asymptomatic
- Tertiary- gummatous (non-cancerous soft tissue growth in syphilis) skin lesions, neurological and vascular manifestation
How is Syphilis treated?
No vaccine, use antibiotics
What is the route of transmission in congenital syphilis?
Vertical transmission from mother to child
miscarriage, still birth, premature, bone disease etc
Describe HSV in particular types 1 & 2
Members of HHV (human herpes virus)- Large DNA virus
Type 1- causes oral infections
Type 2- causes genital infections
What is the mode of transmission of HSV 1 & 2
Direct contact
Give some clinical features observed in HSV 1 & 2
- Painful vesicular rash (heals over 2-4 weeks, appears in same place as multiple blisters)
- Eczema herpeticum
- Eczema encephalitis
How does T.pallidum affect the transmission of HIV?
Increases HIV transmission
What is the reactivation and reinfection seen in HSV 1 &2 and VZV due to?
Latency period
How are HSV 1&2 treated?
No vaccine, use antivirals like Acyclovir
Describe VZV and the disease it causes?
varicella zoster virus (also a HHV), causes chickenpox mainly in those younger than young adults, causes shingles in adults
-widespread vesicular rash
Why can there be serious consequences with VZV infection?
Affects CN V1 (ophthalmic branch of trigeminal nerve)
Is there a vaccine for VZV?
yes, can also use antivirals
What is a dermophyte?
type of fungus that particularly affects parts of the body that have keratin e.g Trichophytum rubrum
Describe Tricophytum rubrum
- dermophyte
- common cause of superficial fungal infections
What infections are associated with T.rubrum?
Tinea capitis (scalp)- Kerion is a type Tinea mauum (hand)
State another form of fungal infection distinct from dermophytes.
Yeast e.g Candida
-grows on war wet surfaces (aka thrush when in mouth)
What are some clinical features of an infections with T.rubrum?
- erythromatous scaly rash on skin/scalp
2. discoloured or crumbly nails
What is Scabies?
skin infestation by the mite Sarcopetes scabei
Outline the pathogenies of Scabies
- mite burrows into surface of skin, exposure to faeces and eggs causes a delayed-type allergic reaction.
- leads to widespread eczematous rash approx 4 weeks after first infestation
- very itchy
Where are the burrow sites in Scabies?
Genital regions Nipples Axilla Wrists Finger webs
How is Scabies transmitted?
Skin-skin contact
How is Scabies treated?
Topical systemic insecticide
