Skin, rashes and infections Flashcards
What is chickenpox also known as?
herpes zoster
What causes chickenpox?
varicella zoster
What is the incubation period of chickenpox?
1-3 weeks
What is the prodrome for chickenpox?
nausea myalgia anorexia headache malaise
Explain the nature of the rash in chickenpox
Starts on head and trunk Progresses to peripheries 1. Macule to papules 2. Vesicles (itchy) 3. Pustules 4. Crusts w/in 5 days1
How is chickenpox spread?
personal contact and droplets
What is the treatment for chickenpox?
its self-limiting
topical calamine for itch
Chlorphenamine if >1yr
If immunocompromised: IV aciclovir
What are the complications of chickenpox?
- Secondary bacterial infection(staph, group A strep) -> TSS, NF
- Encephalitis -> VZV associated cerebellitis
- Purpura fulminans
- Primary VZV in immnocomp -> severe disseminated disease
What is the cause of rubella?
Rubella virus
What is the incubation period of rubella?
2-3 weeks
When is someone with rubella infectious?
5 days before and after start of rash
What are the signs of rubella other than rash?
Prodrome of mild fever
Lymphadenopathy
What is the nature of the rash in rubella?
Maculopapular rash on face which spreads to whole body Not itchy (unlike adults)
How long does a rubella rash take to fad?E
3-5days
What are the ix for rubella
can be confirmed serologically
What is the rx of rubella
self-limiting
prevention in immunisation
inform HPT
What are the complications of rubella
arthritis
encephalitis
thrombocytopenia
myocarditis
What is the cause of mumps?
RNA paramyxovirus
What is the incubation period of mumps?
2-3 weeks
wHEN IS mumps contagious?
7 days before and 9 days after parotid swelling
What are the features of mumps?
prodrome malaise and increased temp
painful parotid swelling unilateral -> bilateral
mild rash
What is rx of mumps
rest
prevention in immunisation
notifiable
What is the cause of measles?
RNA paramyxovirus
How is measles spread?
droplets
What is the incubation period of measles?
10-14days
wHEN is measles contagious?
prodrome until 4 days of rash
What are the features of measles?
prodrome: fever, cough, coryza, conjunctivitis
Koplik spots
Describe the nature of measles rash
Spread downwards from behind ears to whole body
discrete maculopapular rash becoming blotchy and confluent
What is the treatment of measles?
self-limiting
painkillers
notifiable
what is rx of measles in immunocompromised?
ribavirin
What is the cause of HSP?
IgA mediated small vessel vasculitis
What are the features of HSP?
SMALL artery biopsy showing IgA deposition
increased ESR
proteinuria
What are the features of HSP
- Abdo pain
- Polyarthritis
- IgA nephropathy: haematuria, proteinuria, rbc casts
describe the nature of HSP rash
palpable purpura on extensor surfaces of feet, legs, arms and buttocks w localised oedema
What is the cause of slapped cheek syndrome?
parvovirus B19
How is SCS spread?
resp route
direct contact w nose/throat discharges
Describe the rash in SCS
Slapped cheek facial rash week after viraemic phase
progressing to maculopapular ‘lace’ like rash on trunk and limbs
What isn’t usually involved in a rash in SCS?
palms and soles
What is the rx of SCS?
SELF-limiting
what are the complications of SCS?
aplastic crisis
fetal disease
When is SCS no longer infectious?
when rash appears
What is the cause of scarlet fever?
reaction to erythrogenic toxics produced by Group A haemolytic streptococci - usually S. Pyogenes
What is the incubation period of scarlet fever?
2-4 days
What are the features of scarlet fever?
fever 1-2days sore throat malaise, headache, N&V flushed face + circumoral pallor strawberry tongue
How is scarlet fever diagnosed?
throat swab
Describe the nature of the rash in scarlet fever
red-pinprick blanching rash on the chest, axillae or behind ears
When does a rash appear in scarlet fever?
12-48hrs after fever
what is the treatment of scarlet fever?
penicillin 10 days (start before results of throat swab)
clarithromycin if pen allergic
notifiable
What are the complications of scarlet fever?
otitis media
rheumatic fever
acute glomerulonephritis
sydenhams chorea
What is the cause of eczema?
Multifactorial:
genetic - atopy, FHx
infection
What is needed for a diagnosis of eczema?
Diagnosis: itchy skin + ≥3: 1. Onset <2yrs 2. Past flexural involvement 3. Hx of dry skin 4. PHx of other atopy Visible flexural dermatitis
What ix are done for eczema?
increased plasma IgE
RAST
skin prick
What are the features of eczema?
pruritus (main sx)
excoriations that become red, weeping and crusted
dry skin
lichenifications due to XS scratching + rubbing
What is the treatment of eczema?
- Emollients - equal parts liquid paraffin and soft paraffin
- Topical CS
- Immunomodulators: tacrolixus, pimecrolimus
What can be used to help break the itch cycle in eczema?
sedating anti-histamines -hydroxyzine at night
What is a complication of eczema and how is it treated?
infection - abx w hydrocortisone
What is the cause of ITP
Immune mediated reduction in platelet count