Viral skin infections Flashcards
What causes both chicken pox and shingles ?
Varicella Zoster virus
Describe who are the usual affected individuals of chicken pox and what happens after the infection has subsided ?
- Typically occurs in children
- After subsiding the virus establishes latency in dorsal root ganglion
What are the main symptoms of chicken pox ?
- Fever initially then other symptoms develop
- Itch
- Systemic upset is usually mild
- Rash - goes from macules to papules to vesicles to scabs to recovery
How is chickenpox diagnosed ?
Clinically
What are some of the complications of chicken pox ?
- Secondary bacterial
- Pneumonitis
- Disseminated haemorrhagic chickenpox
- Scarring, absent or minor
- Encephalitis (inflammation of the brain, caused by infection or an allergic reaction)
Pic below shows a haemorrhagic rash caused by chicken pox
What should not be given to patients with chickenpox and why?
NSAID’s - because it increases the risk of secondary bacterial infection
Appreciate this story of a man developing varicella penuomia
A 26-year-old man presented with a 5-day history of cough, fever, and mild dyspnoea. He had an exanthematous vesicular rash that had started 3 days before the respiratory symptoms began. He smoked cigarettes (30 per day for the previous 14 years). His daughter had recently had chickenpox; he had not been vaccinated against the disease nor did he have a history of it. A skin examination revealed a polymorphic rash with vesicles, pustules, and crusty lesions (Panel A). Chest radiography performed at the time of admission to our hospital showed multiple small nodules in both lungs (Panel B). There was no evidence of central nervous system or liver involvement. High-resolution computed tomography revealed numerous ill-defined nodules, 1 to 5 mm in diameter. Coalescence and surrounding halos of ground-glass attenuation were also observed in some nodules (Panel C). Serologic testing for the human immunodeficiency virus was negative. The diagnosis of varicella pneumonia was made on the basis of the rash, pulmonary symptoms, and contact with a child with chickenpox. The patient was treated with intravenous acyclovir. Follow-up chest radiography, performed 7 days after admission, showed that the nodules had disappeared. The patient had a full recovery.
What is neonatal varicella zoster virus ?
It is when the mother gets chickenpox dring pregnancy which can then be passed on to the baby associated with more sever complications
In who may chickenpox present more severe ?
- Very young (neonates) or very old patients
- Immunocompromised
What is the treatment of chickenpox in health individuals ?
- Paracetamol + calamine lotion for the itch
- Keep cool & trim nails
For immunocompromised patients & newborns with peripartum exposure to chickenpox (i.e. havent yet developed it themselves) what should be given?
Varicella zoster immunoglobulin (VZIG).
If an immunocompromised patient or neonate develops chickenpox what should be given to treat it ?
IV aciclovir
What is given to pregnant women if they have exposure to someone with shingles/chickenpox?
Varicella Zoster Immune Globulin
What should be given to pregnant women who are found to be seronegative for varicella-zoster virus immunoglobulin G (VZV IgG)
Varicella vaccination prepregnancy or postpartum
If a pregnant women develops chickenpox what treatment should be given ?
- PO aciclovir if they present within 24 hours of the onset of the rash and if they are 20+0 weeks of gestation or beyond.
- For severe chickenpox all pregnant women should recieve IV aciclovir
What is shingles (or herpes zoster) ?
- Shingles is an acute, unilateral, painful blistering rash caused by reactivation of the Varicella Zoster Virus (VZV).
- It is also known as herpes zoster
What are some of the features/symptoms of shingles ?
- There is usually a prodromal phase with abnormal skin sensations and pain in the affected dermatome e.g. burning, stabbing, throbbing for 2-3 days before rash appears
- Dermatomal distribution
- Tingling/neuralgic type pain to erythema, to vesicles, to crusts
How is shingles diagnosed ?
Clinically
Who is shingles more common in ?
More common in the elderly and immunocompromised
What is it reffered to as if patients experience pain due to shingles for greater than 4 weeks
Post herpetic neuralgia
Post herpetic neuralgia affects nerve fibers and skin, causing burning pain that lasts long after the rash and blisters of shingles disappear.
What is herpes zoster ophthalmicus ?
- Herpes zoster ophthalmicus (HZO) describes the reactivation of the varicella-zoster virus in the area supplied by the ophthalmic division of the trigeminal nerve.
What are the clinical features of herpes zoster ophthalmicus ?
- vesicular rash around the eye, which may or may not involve the actual eye itself
- Hutchinson’s sign: rash on the tip or side of the nose. Indicates nasociliary involvement and is a strong risk factor for ocular involvement
What is the management of herpes zoster ophthamicus ?
PO aciclovir + urgent referral for ophthalmology review +/- topical corticosteroids
What is wrong with this patient ?
Patient has shingles which is affecting the maxillary division of the trigeminal nerve
What is wrong with this patient ?
They have shingles which is affecting the mandibular division of the trigeminal nerve
What is ramsay-hunt syndrome and what are some of the complications of it ?
Ramsay Hunt syndrome (herpes zoster oticus) occurs when a shingles outbreak occurs in the geniculate ganglion of the seventh cranial nerve.
What are the clinical features of ramsay-hunt syndrome ?
- Auricular pain is often the first feature
- Facial nerve palsy
- Painful vesicular rash around the ear & in the auditory canal
- Other features include vertigo, tinnitus, loss of taste, dry eyes/mouth & deafness
What is the treatment of ramsay-hunt syndrome ?
PO aciclovir + prednisolone
Herpes zoster (shingles) is uncommon to affect people < 10yrs old but when it does occur what is the difference between it and when it affects people in older age groups ?
Difference is the lesions have a predilection for dermatomes supplied by the cervical and sacral nerves. In adults, the lesions are more common in the lower thoracic and upper lumbar dermatomes and may involve the trigeminal nerve.
Pic shows an area affected by herpes zoster in a 19month infant
What is the vaccination for chicken pox and who is it used for ?
- It is live attenuated varicella zoster virus
- Mainly used for susceptible health care workers
Is the vaccination for shingles the same as the one for chicken pox and who is this vaccination mainly used for ?
Yes - it is offered to 70-79 year olds reduce the impact of shingles
What is the main contraindication to the chickenpox and shingles vaccination ?
Immunocompromise because it is a live-attenuated vaccine
What could have caused the scarring pattern and red eye shown in the pic below ?
Opthalmic zoster
Note it can damage eye sight
What are the 2 main types of herpes simplex viruses and what are the different areas they mainly infect ?
There is HSV type 1 and 2
HSV type 1:
- Main cause of oral lesions
- Causes half of genital herpes
- Causes encephalitis
HSV type 2:
- Rare cause of oral lesions
- Causes half of genital cases
- Encephalitis / disseminated infection (particularly in neonates)
What is oral HSV & what is the primary cause of it ?
- Oral herpes simplex virus (HSV) usually causes a mild, self-limiting infection of the lips, cheeks, or nose (herpes labialis or ‘cold sores’) or oropharyngeal mucosa (gingivostomatitis)
- HSV-1 accounts for > 90% of cases
What are the main signs of oral herpes simplex virus infection ?
Prodrome of fever, general malaise, sore throat, & cervical & submandibular lymphadenopathy
Cold sores:
- Burning, tingling, itching & paraesthesia preceed lesions
- Crops of vesicles that rupture leaving superficial ulcers that crust over & heal. Typically occuring at the mucomembranous junction of the lips (the transition from skin to mucous)
Gingivostomatitis:
- Sore mouth or throat + excess salavation & drooling
- Crops of vesicles on a red swollen base that rupture forming ulcers on the pharyngeal & oral mucosa (palate, buccal mucosa, tongue, gingiva & floor of the mouth)
- Ulceration may be covered by a yellow/grey membrane
How is oral HSV infection diagnosed?
Clinically
What is shown in the pic ?
Herpes simplex
What is the anti-viral used to treat both severe chicken pox, shingles and severe HSV infections ?
PO Aciclovir
What is the specific treatment of oral herpes simplex infection ?
- gingivostomatitis: oral aciclovir, chlorhexidine mouthwash
- cold sores: topical aciclovir
How are HSV and VSV(shingles and chicken pox) infections diagnosed if not made clinically alone?
Swab with viral transport - preferred test for viral skin / mucous membrane infections
Antibody tests –where virus infected site is inaccessible or as adjunct to swab
Describe the action of aciclovir
- It is a guanosine analogue:
- It is selectively incorporated into viral DNA inhibiting replication
What is erythema multiforme ?
A hypersensitivity reaction usually triggered by infections, most commonly herpes simplex virus (HSV). It presents with a skin eruption characterised by a typical target lesion.
What are the tirggers for erythema multiforme ?
- Mainly infections - esp HSV, Mycoplasma pneumoniae bacterium may also cause it
- Drugs may also trigger it e.g. penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
What are the clinical features of erythema multiforme ?
- Few-hundreds of skin lesions
- Lesions 1st appear on hands &/or tops of feet & then spread to the limbs and then trunk
- May have associated itch or burning sensation
Typical target lesions are sharply demaracated, round shaped with 3 zones:
- The centre is dusky or dark red with a blister or crust
- Next ring is a paler pink and is raised due to oedema (fluid swelling)
- The outermost ring is bright red.
What is it known as if mucosal involvement occurs in someone with erythema multiforme ?
Erythema multiforme major:
- Most commonly lips, inside the cheeks, tongue
- Less commonly floor of the mouth, palate, gums.
- Mucosal lesions consist of swelling and redness with blister formation. The blisters break quickly to leave large, shallow, irregular shaped, painful ulcers that are covered by a whitish pseudomembrane. Typically the lips are swollen with haemorrhagic crusts.
What condition is shown?
Erythema multiforme
How is erythema multiforme diagnosed ?
Clinically
What is the treatment of erythema multiforme ?
Usually none due to self-limiting course
What is molluscum contangiosum ?
A common skin infection of childhood caused by molluscum contagiosum virus (MCV), that causes localised clusters of epidermal papules called mollusca.
Is molluscum contangious ?
Yes - transmission occurs directly by close personal contact, or indirectly via fomites (contaminated surfaces) such as shared towels and flannels.
Who does molluscum contangiosum typically occur in ?
Children
Who is Molluscum contagiosum most common in and what is the management plan of people with it ?
Common in children
Management:
- Usually self-limiting
- Can be treated with local application of liquid nitrogen
What are the clinical features of molluscum contagiosum ?
- Clusters of firm small round papules
- Papules may be flesh coloured or white
- Papules have a waxy, shiny look (pearly)
- Papules have a small central pit, described as umbilicated
- Papules contain white cheesy material
What is the condition shown ?
Molluscum contagiosum
How is molluscum contangiosum diagnosed ?
Clinically
What is the treatment of molluscum contangiosum ?
- Usually no treatment - provide reassurance, pontaneous resolution usually occurs within 18 months.
- If troublesome can use cryotherapy
What is a viral wart?
- A very common growth of the skin caused by infection with human papillomavirus (HPV).
- A wart is also called a verruca
There are hundereds of HPV genotypes, what are the important ones to remember and what are they associated with ?
6&11 and 16&18 are the ones to remember
- 6&11 are associated with causing genital warts (>90%)
- 16&18 infection are associated with significantly increasing the risk of cervical cancer, the also increase the risk of penile cancer
- 16 is also associated with increasing risk of oropharyngeal cancers
What types of HPV usually cause viral warts ?
Mainly HPV types 1-4
Who are viral warts most common in ?
Children
What are the clinical features of viral warts ?
- Common warts: Firm, raised papules with a rough surface that resembles a cauliflower (common on knuckles, knees, and fingers) — usually asymptomatic but may be tender.
- Periungual warts are common warts around the nails that can be painful and disturb nail growth
- Plane warts: usually round, flat-topped, and skin coloured or greyish yellow (common on the backs of hands).
- Filiform warts: finger-like appearance and may have a stalk (more common on the face and neck).
- Palmar and plantar warts: grow on the palms and the soles of the feet (verrucae). They often have central dark dots (thrombosed capillaries) and may be painful.
- Mosaic warts occur when palmar or plantar warts coalesce into larger plaques on the hands and feet.
What is shown in the pic ?
Viral warts
What is shown in the pic?
Viral warts
How are viral warts diagnosed ?
Clinically
What is the treatment of viral warts?
Topical salicylic acid or cryotherapy
What is herpangina ?
It is the name given to painful mouth and throat ulcers due to a self-limited viral infection
What is the cause of herpangina ?
Enteroviruses - Coxsackie virus (A16 most common), Echovirus
Who is herpangina most common in ?
Children < 10
What are the clinical features of herpangina ?
- Fever & general malaise
- Sore thorat & pain on swallowing
- Small blisters which form tiny yellowish ulcers with a red rim. Usually at the back of the mouth & throat
- It is a self-limiting condition
How is herpangina diagnosed ?
Swab of lesion or sample of stool for enterovirus PCR
What is the treatment of herpangina?
None, it is a self-limiting condition
What is hand, foot & mouth (HFM) disease?
- A common self-limiting viral infection most often affecting young children.
- It is characterised by blisters on the hands, feet and in the mouth
Who is typically affected by HFM disease?
Children - typically occurs in outbreaks at nursery
What is the cause of HFM disease?
Enteroviruses - most commonly coxsackie A16 and enterovirus 71
What are the clinical features of HFM disease?
- Mild systemic upset: sore throat & fever
- Oral ulcers
- Followed later by vesicles on the palms & soles of the feet
- Red macules & papules on buttocks
How is HFM disease diagnosed ?
Clinically
What is the management of HFM disease ?
- Reassurance that it is self-limiting & is not related to HFM disease in animals
- Hydration & analgesia
- Child does not need to be excluded from school but children who are unwell should be kept off school until they feel better
What is one of the complications of hand, foot and mouth disease due to enterovirus 71?
Brain stem encephalitis
What is erythema infectiosum ?
- A common childhood infection causing a slapped cheek appearance and a rash.
- It is also known as fifth disease
What causes erythema infectiosum ?
(erythrovirus) Parvovirus B19
Who is mainly affected by erythema infectiosum ?
Usually children, but can also affect adults
What sort of complications can arise due to infection with the parovirus B19?
- Spontaneous abortion
- Aplastic crises - sudden drop in haemoglobin
- Chronic anaemia - in immunosuppressed patients
- Polyarthropathy esp in infected adults (painful, swollen joints)
How is erythema infectiosum diagnosed ?
Usually clinical signs alone are enough but to confirm diagnosis do:
Parvovirus B19 IgM test
What is the treatment of erythema infectiosum ?
None required, advice rest, hydration & analgesia
Is school exclusion required for someone with erythema infectiosum ?
No as once rash appears they are non-infectious
What is orf (scabby mouth) & what causes it?
- A zoonotic viral skin infection that is contracted from sheep and goats.
- It is caused by the parapox virus
Who does orf primarily affect?
Primarily seen on the hands of farmers
What are the clinical features of orf?
- Lesions are usually solitary or few in number
- A small, firm, red or reddish-blue lump enlarges to form a flat-topped, blood-tinged pustule or blister
- . Characteristically, although there appears to be pus under the white skin, incising this will reveal firm, red tissue underneath.
How is orf diagnosed and managed?
- Diagnosed clinically
- No treatment needed condition is self-limiting & clears up in around 6 weeks
What is shown in the pic ?
Orf
What is lyme disease and what is it caused by ?
- It is an infection caused by a bacteria called Borrelia burgdorferi.
- Lyme disease can affect any part of the body, most commonly the skin, central nervous system, joints, heart, and rarely the eyes and liver.
What is the vector which transmits lymes disease to humans ?
Ticks
What are the clinical features of lymes disease?
Early features:
- Erythema migrans - ‘bulls-eye rash’
- Systemic symptoms: malaise, fever, arthralgia
Later features
- CVS: heart block, myocarditis
- neurological: cranial nerve palsies, meningitis
- polyarthritis
What sign is shown here and what is it diagnostic of ?
- Erythema migrans - diagnostic of lymes disease in early stages
- Erythema migrans = small papule often at site of the tick bite which develops into a larger annular lesion with central clearing, ‘bulls-eye’.
How is lymes disease diagnosed?
Diagnosis - Erythema migrans is diagnostic and does not need lab confirmation. But if caught at late presentation then blood test for antibodies carried out:
- 1st line = enzyme-linked immunosorbent assay (ELISA) test
- 2nd line if 1st line pos. or equivocal = results should be confirmed by Western immunoblot.
What is the treatment of lymes disease?
- 1st line = PO doxycycline
- 2nd line = amoxicillin if dox contraindicted e.g. pregnancy
What are the signs and symptoms of zika virus infection ?
Only 1 in 5 infected become ill - severe disease is rare. Symptoms occur approx 10 days after being bitten by an infected mosquito
•Symptoms include:
- Mild fever
- Rash (mostly maculopapular)
- Headaches
- Arthralgia
- Myalgia
- Non-purulent conjunctivitis
How is the zika virus spread and what are some of the complications the infection can cause ?
By mosquitoes
Can cause:
- Microcephaly - abnormal smallness of the head, a congenital condition associated with incomplete brain development.
- Guillain-Barré syndrome (GBS) is a disorder in which the body’s immune system attacks part of the peripheral nervous system. The first symptoms of this disorderinclude varying degrees of weakness or tingling sensations in the legs.
- People at risk are pregnant mothers due to complications like microcephaly
Where is zika virus most common ?
Endemic in dozens of tropical countries
How is zika virus diagnosed ?
- Diagnosed by tclinical symptoms after a mosquito bite in an endemic area.
- The infection is confirmed by specific serological tests for zika virus immunoglobulins (IgG and IgM),
What is the treatment of zika virus ?
Zika virus infection is usually self-limiting and resolves with supportive therapy
What is eczema herpeticum?
A disseminated viral infection characterised by fever and clusters of itchy blisters or punched-out erosions
What is eczema herpeticum caused by ?
Primary infection of the skin by herpes simplex virus 1 or 2.
Who does eczema herpeticum most commonly occur in ?
Children with atopic eczema/dermatitis
What are the clinical features of eczema herpeticum?
- Eczema herpeticum starts with clusters of itchy and painful blisters.
- On examination, blisters are described as monomorphic punched-out erosions (circular, depressed, ulcerated lesions)
- The patient is unwell, with fever and swollen local lymph nodes.
- It may affect any site but is most often seen on face and neck. May become widely disseminated throughout the body
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What is shown in the pic ?
Eczema herpeticum
How is eczema herpeticum diagnosed ?
viral swabs taken by scraping the base of a fresh blister for either viral culture, PCR or Direct fluorescent antibody stain
What is the treatment of eczema herpeticum and why ?
Treatment is admission for IV aciclovir because the condition can rarely be fatal
