Viral Skin Infections Flashcards
What causes chicken pox?
- varicella zoster virus
How is chicken pox spread?
- respiratory droplets
- personal contact
What is the incubation period for chicken pox?
14 - 15 days
What is the presentation of chicken pox?
- fever
- malaise
- anorexia
- ## rash (centripetal, vesicular)
How would you describe the chicken pox rash?
- centripetal (trunk) vesicular :
- errythmatous —> macules —> papules —> vesicles –> pustulates —> resoution
- **Intensley pruritic
- may see excoriations
What are the complications of chicken pox?
- Shingles (herpes zoster) = reactivation of dormant virus in adults. - dermatomal distribution
- sever pneumonitis in pregnancy
- CNS (benign cerebellar ataxia syndrome, acute encephalitis (rare)
- thrombocytopenic purpura
Apart from clinical diagnosis of chickenpox - what other invx can be done to confirm?
- PCR of vesicluar fluid
What is the treatment of chicken pox?
- oral aciclovir
IV in neonates or severe disease
How is herpes simplex virus spread?
direct contact
Which type of herpes simplex virus affects the face vs the genitals?
HSV1 = face HSV2 = genitalia
How does HSV1 affect the face?
colesores- small vesicular lesions that crust and heal over but may cause pain.
- malaise
- lymphadenopathy
How does HSV2 affect the genitals?
- ulcers after vesicles break down
What are the triggers of reactivation of HSV?
- immunosuppression
- stress
- illness
- sunlight
- trauma
What are the prodromal effects of HSV?
- tingling / stinging
What is the treatment for HSV?
topical aciclovir (oral if severe or genital)
What are the complications of herpes zoster opthalmicus?
PEELS:
- ptosis
- ectropion
- entropion
- lid scarring
- SCLeritis (scleral, corneal, limbal atrophy)
- inflammation of cornea / optic nerve /retina / choroid = permanent vision loss
- postherpetic neuralgia
What causes molluscum contagiosum and who is usually affected??
Pox virus
- children affected
describe the skin manifestations of molluscum contagiousum?
- pearly white (slightly pink), well demarcated papules, umbilicated centre, pus filled - when squeezed , cheesy white fluid comes out.
Molluscum contagiosum is self limiting - how long does it take to go?
- usually takes 6-12 weeks for the lesion to go but then the virus spreads elsewhere.
- overall takes 12-18months to completely get rid of virus
What are the non specific symptms of HIV?
- rash
- viral like prodrome (headache)
- arthralgia
- myalgia
- pyrexia
What special tests are done for HIV?
- Capsid protein p24
- CD4+ count
- GP120 and GP41
What do the bloods for HIV show?
- anaemia
- lymphocytopenia
- thrombocytopenia
- Raised CRP
- raised AST / ALT
What is the incubation period for HIV?
2 - 6 weeks
What does the skin look like in the primary manifestation of HIV (seroconversion illness)?
- Diffuse Macular - papular rash
- face, neck, trunk affected
- lasts 2-3 weeks
After the primary manifestation of HIV on the skin how does this progress?
- Seborrhoeic Dermatitis (in 50% of HIV patients)
- Greasy scales, underlying inflammatory eczema - very itchy.
- affects NAMES - nasal creases, anterior chest, moustache, eyebrows, scalp
What is the treatment for Seborrhoeic Dermatitis (affects 50% of HIV pts)
- ketaconazole shampoo
- topical steoid
- imidazole in resistant cases
What causes viral warts?
HPV
Which virus that causes warts is linked to cervical cancer? and what are the risk factors ?
HPV 16 and 18
- folate deficiency
- UV
- smoking
- immunosupression
How would you describe the appearance of a viral wart?
- exophytic warty lesion
- papules
- filiform (finger like projections)
When would you suspect malignant change in a viral wart?
- sudden change in appearance or size
- pain
What are the treatments for viral warts?
1) topical salicylic acid ( but 70% recur)
2) Cryo (but painful and causes scarring)
3) diathermy loop cauteristion
