Skin Infections Flashcards
what are the 3 bacterial skin infections
impetigo, cellulitis, necrotising fasciitis
what is impetigo?
infectious disease affecting kids spread by direct contact
what is the appearance of impetigo?
inflamed plaques with a golden/ crusted surface around mouth and nose
organisms responsible for impetigo?
staphylococcus aureus, streptococcus pyogenes
mx for impetigo?
topical fusidic acid & avoid school/work until lesions dry
what is the main complication of impetigo?
toxin induced bullous impetigo- abs tx (fluclox / erythromycin)
what is cellulitis
infection of the skin and soft tissue underneath
aetiology of cellulitis
skin barrier breach
organisms of cellulitis
staphylococcus aureus, streptococcus pyogenes (GroupA) or GroupB, immunocompromised usually gram -ve/anaerobes
s/s of cellulitis
cardinal signs of inflammation, leather like, may have golden yellow crust if staph A, generalised swelling
common areas of cellulitis
lower leg/arm, peri-anal, peri-orbital
what is the classification for cellulitis
Eron Classification 1- no systemic toxicity or morbidity 2- systemic toxicity or comorbidity 3- significant systemic toxicity / significant comorbidity 4- sepsis
mx for cellulitis
elevate, analgesia, splint, abx (fluclox, clarithromycin, clindamycin, co-amoxi)
what is necrotising fasciitis
rapidly spreading, deeper bacterial infection of subcutaneous tissues
necrotising fasciitis usually occurs following _____ / _____
trauma / surgery
what are the 2 types of necrotising fasciitis
T1: mix of aerobic/ anaerobic bacteria
T2: group A streptococci, spontaneous
what is a very rare cause of necrotising fasciitis
vibrio species (asiatic cholera)
s/s of NF?
severe pain that is unproportional to degree of skin inflammation, high WBC/CRP
abx for NF?
benzylpenicillin & clindamycin
surgical mx of NF?
surgical debridement and exploration- may result in amputation
what are the viral skin infections studied?
chicken pox herpes simplex virus erythema multiforme molluscum contagiosum warts herpangina erythema infectosum (slapped cheek disease) Orf syphillis Lyme disease zika
what is chickenpox and shingles?
chickenpox- primary infection
shingles- reactivation
T/F: shingles happens in kids
F: in adults, chickenpox in kids
what is the organism that causes chicken pox?
varicella zoster virus
s/s of chickenpox and shingles
chickenpox: macules> papules > vesicles > scabs
fever, headache, itch*
shingles: tingling pain to erythema > vesicles (one sided only) > curses + neuralgic pain (dermatomal distribution)
mx for chickenpox?
live attenuated vaccine
+ stay away from school, loose clothes, paracetamol
when do you give antivirals (acyclovir) for CP?
> 16yo and susceptible population
mx of shingles?
may take up to 4 weeks, acyclovir if immunocompromised or if CN involvement, stay off work
complication of chicken pox?
pneumonia
complication of shingles?
post herpetic neuralgia
herpes simplex virus s/s?
extensive ulceration in and around mouth, lasts 1 week, blistering rash at vermillion border
types of HSV?
t1: oral lesions, genital herpes, encephalitis
t2: genital herpes, oral lesions less common, encephalitis
T/F: cold sores are t1 HSV related?
T
Ix for HSV?
clinical or HSV DNA in vesicle fluid sample via PCR
mx of HSV?
oral valaciclovir, acyclovir for T2/ cold sores
complications of HSV?
other HSV infections- corneal ulcers, eczema herpeticum, chronic peri-anal ulceration
s/s of erythema multiform?
target lesions with erythema on the distal limbs with mucosal involvement e.g. conjunctivitis
describe the target lesions of erythema multiform?
concentric rings of erythema with dusky centre
aetiology of erythema multiform?
drug reaction, HSV infection, off, mycoplasma
mx of erythema multiform?
self limiting, recurrence- acyclovir
what organism is responsible for molluscum contagiosum?
pox virus
s/s of molluscum contagiosum?
fleshy, firm, umbilicate, pearlescent nodules
mx for molluscum contagiosum?
lasts months but is self-liming, liquid nitrogen (cryo) therapy
what are warts?
small lumps of skin caused by human papilloma virus
types of warts?
common warts
plantar warts (verrcuae)- flattened papillomatous surface, may be tender
plane warts: flesh coloured flat-topped lesions, multiple
anogenital warts
how are warts spread?
direct contact
tx for warts?
may spontaneously clear, keratolytic agents (salicylic acid), cryotherapy
organism responsible for herpangina?
enteroviruses- coxsackie, echovirus
s/s of herpangina?
blistering rash of back and mouth
foot and mouth is a coxsackie caused subtype of which disease?
herpangina
erythema infectosum is also known as what?
slapped cheek disease
what is erythema infectosum?
viral infection that causes blotched or raised red rash and a slapped cheek appearance
what is the organism that causes erythema infectosum
parvovirus B19
s/s of erythema infectosum?
fever, slapped cheek rash, lacy rash on arms/ legs/ trunk
in adults wrist arthritis may be present
ix for erythema infectosum
AB testing for parvovirus
mx for erythema infectosum?
supportive- symptomatic tx
complications of erythema infectosum?
abortion, aplastic crisis (drop in haemoglobin), anaemia
what is Orf
pox virus infection mainly affecting mouth
T/F: Orf is caused by Pox virus transmitted via monkeys
F: Pox virus transmitted via sheep and goats therefore more common in farmers and young kids at petting zoos
s.s of Orf?
red papule on hands with inflamed blistering border
mx for Orf?
self-limiting
T/F: syphilis is sexually transmitted
T
types of syphilis
1y: chancre present (painless ulcer at site of entry)
2y: red rash over body + oral lesions
3y: CNS and CV involvement
what is the bacterium responsible for syphilis?
treponema pallidum
mx for syphilis
penicillin injection
epi of Lyme disease?
countryside- May to September
organism that carries Lyme disease?
tick which carries borellia burgdorferi bacterium
s/s of Lyme’s?
early- erythema migrant (bull’s eye), fever, headache
late- heart block, nerve palsies, arthritis
tx for Lyme’s?
doxycycline/ amoxicillin
Zika virus is found in which countries?
tropical- Brazil*
organism of Zika and its vector?
aedes aegypti carried by mosquito
s/s of Zika?
fever, maculopapular rash, headaches, arthralgia, myalgia, non-purulent conjunctivitis
mx of zika?
self resolves 2-7 days after onset
main complications of Zika
pregnant women as may cause microcephaly, G-B syndrome
