Viral infections of the skin Flashcards
What virus causes chickenpox and shingles?
Varicella zoser
When are you likely to get chickenpox?
Primary infection typically in childhood that stays latent in the sensory nerve roots
What is shingles?
Reactivation of latent varicella virus to form zoster
Only flares up in one dermatome
What is the progression of the chickenpox disease?
Macules to papules to vesicles to recovery
Centripetal with inflammed skin
Fever
Itch
When is someone with chickenpox no longer infectious/
When the spots have scabbed over
What are complications of chickenpox?
Secondary bacterial infection in the skin Pneumonitis Haemorrhagic Scarring, absent or minor Encephalitis Purpuric haemorrhagic rash
Who is likely to get severe chickenpox?
Extremes of age (elderly and newborns)
Depressed cell mediated immunity
What can occur if you get chickenpox whilst pregnant?
Foetal varicella syndrome
How can a newborn get VZV?
If a women get chickenpox within 5 days of delivery the child can get neonatal chickenpox which has a high mortality
What is the progression of shingles?
Tingling pain to erythema and to vesicles to crusts
What type of pain is zoster pain?
Neuralgic in character
What is post herpetic neuralgia?
Pain beyone 4 weeks of the virus after the rash has cleared up
Who is most likely to develop post herpetic neuralgia?
Elderly and those with trigeminal distribution
What is opthalimc zoster?
Zoster in opthalmic division of trigeminal nerve that requires an urgent referral to an opthalmologist
Where is shingles likely to distribute if in children under 10 (this is very rare)?
Dermatomes supplied by the cervical and sacral nerves
Where is shingles likely to distribute in adults?
Lower thoracic and upper lumbar dermatomes and may involve trigeminal
What is ramsay hunt syndrome?
Vesicles and pain in auditory canal and throat that can cause facial palsy and irritation of the 8th cranial nerve *deafness, vertigo, tinittus)
What can herpes simplex virus cause?
Primary gingivostomatits in pre-school children
Extensive ulceration in and around mouth`
How would you describe herpes simplex virus?
Blistering rash at vermillion border that can be spread to fingers or eczema
What is eczema herpeticum?
Severe atopic eczema can inoculate herpes simplex from mouth all over the skin causing an infection over the whole skin
What strain of herpes simplex virus causes genital warts?
Herpes simplex type 1 or 2
What strain of herpes simplex causes cold sores?
Type 1
How can VZV and HSV be treated?
Aciclovir - structural analogue of guanosine that gets incorporated into growing viral DNA chains and terminates it
What will erythema multiforme present as?
Target lesions with erythema
What can cause erythema multiforme?
Herpes simplex virus
Mycoplasma pneumoniae bacterium
How does molluscum contagiosum present?
Fleshy, firm, umbilicated, pearlescent nodules 1-2mm in diameter
What causes molluscum contagiosum?
Pox virus
How can molluscum be treated?
Liquid nitrogen
What causes viral warts?
HPV
How can warts be treated?
Keratolytics - topical salicyclic acid
What strain of HPV causes genital warts?
Types 6 and 11
What strains of HPV cause cervical cancer?
Types 16 and 18
What strains of HPV cause warts?
Types 1-4
What is herpangina?
A blistering rash of the back of mouth caused by enterovirus
What causes hand, foot and mouth disease?
Coxsackie virus
Who is most affected by hand foot and mouth disease?
Typically children
What is erythema infectiosum?
Caused by parvovirus B19 that causes a red cheek in children and can cause acute polyarthritis of the small joints in adults
What are some complications of parvovirus B19?
Spontaenous abortion - foetal hydrops as precursor
Aplastic crises - sudden drop in haemaglobin seen in patients with thalassaemia and sickle cell anaemia
Chronic anaemia - in immunosuppresed patients
What is orf?
Firm fleshy nodule on hands of sheep farmers
What is the primary infection of syphilis?
Chancre - painless ulcers at the site of entry
What is the secondary phase of syphilis infection?
Red rash over body that is prominent on feet and palms of hands
Mucous membrane snail track ulcers
What is the tertiary phase of syphilis infections?
CNS
CV
Gummatous
What is a gumma?
A soft, non-cancerous growth resulting from the tertiary stage of syphilis. It is a form of granuloma
How is syphilus treated?
Injections of penicillin
What is the vector for lyme disease?
Ticks
What causes bacterium causes lyme disease?
Borrelia burgdorferi
How does lyme disease present?
Erythema migrans (bullseye, target lesions) Heart block, nerve palsies, arthritis
How is lyme disease treated?
Doxycycline or amoxicillin
What are the symptoms of zika virus?
Mild fever Rash (maculopapular) Headaches Arthralgia Myalgia Non-purulent conjuctivitis
How is zika virus spread?
Mosquito
What are complications of zika virus?
Microcephaly of foetuses
Guillan barre
