Microbio skin infections Flashcards
Describe epidemiology of skin infections
25% of skin-related GP conslultations (skin problems account for 25% GP visits also)
Infection more common in hot, humid, poor environements
Autoimmune common everywhere
Examples of common skin problems
Inflammatory dermatoses eg psoriasis, acne etc fungal infection viral infections bacterial infections parasitic skin infection skin malignancy
Example of bacterial skin infection
Staphylococcus aureus
Treponema pallidum
Example of fungal skin infection
Trichophyton rubrum
Examples of viral skin infection
herpes simplex virus
varicella zoster virus
(human papillomavirus)
Example of parasitic skin infection
sarcoptes scabiei (ectoparasite)
Example of a non-skin related fungal infection
+ where infects
Aspergillus
lungs and liver
Manifestations of Staph. aureus skin infection based of location
Impetigo = subcorneal Boil = hair follicle Carbuncle = multiple adjacent hair follicles Folliculitis = mouth of hair follicle Ecthyma = whole epidermal layer
Features of S. aureus skin infection
Usually crusty, golden (aureus) impetigo around mouth but can affect head, neck and ears
(may cause serious staphylococcal scalded skin syndrome in newborns)
Staphylococcus aureus organism classification
Gram +ve
staphylococcus (spherical chains) bacteria
Treponema pallidum classfication
gram -ve
spirochaetae bacterium
Disease caused by Treponema pallidum
SYPHILIS!!!!!
Transmission of Treponema pallidum
sexual transmission
vertical transmission -> congenital syphilis
Disease course of syphilis
1’ = chancre = painful ulcer at inoculation site (weeks)
2’ = generalised rash + lymphadenopathy (months)
latent phase
3’ = skin, vasculature and BRAIN manifestations (years)
Symptoms of 2’ syphilis
maculopapular rash
palmar and plantar involvement
condyloma lata at anus
Symptoms of 3’ syphilis
Bone lesions -> severe facial and cranial deformity
Gummatous skin lesions
thoracic aortic aneurysm
neurosyphilis
Symptoms of congenital syphilis
miscarraige/stillbirth prematurity rashes bone disease brain and neuro problems
Herpes simplex classification and types and what they cause
dsDNA virus with tegument shell
Type 1 -> oral herpes
Type 2 -> genital herpes
Symptoms of herpes
vesicular rash around mouth or genitals
May cause eczema herpeticum in eczema patients
Why is herpes infection recurrent?
And typical symptom
Virus has latency in neurones
Can migrate to cell body and cause unilateral dermatomal infection
Varicella zoster virus classification and types and what they cause
(also called herpes zoster virus) dsDNA virus with tegument shell Part of human herpes virus family Type 8 Causes CHICKENPOX (preferentially called varicella) and then recurrent infection = SHINGLES (preferentially called herpes zoster)
Symptoms of herpes zoster = SHINGLES
Unilateral dermatomally distributed vesicular/bullous rash
Trichophyton rubrum classification
superficial fungal skin infection with long hyphae
grows in keratin
Types of Trichophyton rubrum based on location
Tinea unguium = toenail Tinea capitis = head/scalp Tinea facei = face Tinea manuum = hand Tinea pedis = foot Tinea cruris = groin
