Skin infections Flashcards
What percentage of GP consultations in the UK are skin related?
15%
What percentage of skin related conditions are due to skin infections?
25%
Which populations are skin infections much more common in?
Hot humid climates and amongst poor populations
What type of bacteria is staphylococcus aureus?
Gram positive
In what percentage of humans is staph aureus commensal?
30% with colonisation in nose, axillae and groins
What is the most common bacterial cause of skin infections?
Staph aureus -skin infections including impetigo, folliculitis, ecthyma, boils and carbuncles
What can staph aureus cause through production of toxins?
Staphylococcal scalded skin syndrome (exfoliative toxin), toxic shock syndrome, food poisoning (enterotoxin) and necrotising soft tissue infections
What else can staph aureus cause?
Bone, joint, lung infection and sepsis
What can staph aureus infection be treated with?
Antibiotics- no vaccine
What is treponema pallidum?
Gram negative spirochaete
What is treponema pallidum the cause of?
Syphilis- STD
What are the stages of syphilis?
Primary- painless ulcer (chancre) at site of inoculation
Secondary- disseminated infection with rash and lymphadenopathy
Latent (asymptomatic) period
Teritary- Skin, neurological and vascular manifestations
How else can syphilis be transmitted?
Vertically- causes congenital syphilis with broad spectrum of clinical manifestations
How is syphilis treated?
Antibiotics- no vaccine
What family do HSV 1 and 2 belong to?
Human herpes family of DNA viruses
What is the difference between type 1 and 2 HSV?
Type 1- usually causes oral infection
Type 2- usually causes genital infections
How is HSV transmitted?
Direct contact- kissing and sex
What does clinical infection with HSV result in?
Painful vesicular rash which heals over 2-4 weeks.
How is HSV treated?
No vaccine but can be treated with anti-viral medication such as acyclovir
What does primary infection with varicella zoster virus cause?
Chicken pox- this manifests with prodrome of fever and malaise followed by development of widespread vesicular rash
How long does primary clinical infection with varicella zoster last?
About 2 weeks.
What happens after primary infection with varicella zoster/herpes is cleared up?
The viruses remain latent in the sensory neurones and can reactivate years later to cause herpes zoster (shingles)/herpes again
What is herpes zoster/shingles?
Reactivation of VZV and painful vesicular rash appears along course of a dermatome- usually heals over 2-4 weeks
What can there be serious consequences with in herpes zoster and why?
The eye if the distribution of the ophthalmic division of the trigeminal nerve is involved
How is varicella zoster treated?
A vaccine is available- anti-viral medicine such as acyclovir is prescribed in certain circumstances
What is trichophytum a common cause of?
Superficial fungal infections
What is trichophytum?
A dermatophyte- type of fungus that particularly infects parts of the body which have keratin e.g. skin, nails and hair.
How are clinical manifestations of tricophytum named?
They have the prefix tinea and then the latin part of the body that they infect e.g tinea capis
What are the clinical manifestations of tricophytum?
Erythematous scaly rash on skin or scalp or discoloured and crumbly nails
How are trichophytum infections treated?
Topical or systemic antifungal medication such as terbinafine
What is scabies?
Skin infestation with the mite sarcoptes scab?
How does scabies develop?
The mite burrows in the surface of the skin and exposure to mite faeces and eggs causes delayed allergic reaction which results in wide spread eczematous rash which usually occurs about 4 weeks after original infestation and usually very itchy
Where can the scabetic burrows be found?
Certain regions of the body e.g. genital region, nipples, wrists, finger webs, instep of the feet and axillae
How is scabies transmitted?
Skin to skin contact
How is scabies treated?
Topical use of systemic insecticides
