Skin infestations and infections 3 Flashcards
What is herpes simplex virus?
Primary and recurrent vesicular eruptions
Where does Herpes simplex virus favour?
- orolabial
- genital regions
When can transmission occur in herpes simplex virus?
even during asymptomatic periods of viral shedding
How is HSV-1 spread?
direct contact with contaminated saliva / other infected secretions
How is HSV-2 spread?
sexual contact
Where does herpes simplex virus replicate?
at mucocutaneous site of infection
How does herpes simplex virus travel?
by retrograde axonal flow to dorsal root ganglia
When do the symptoms of herpes simplex virus come?
with 3-7 days of exposure
What is herpes simplex virus preceded by?
-tender lymphadenopathy
-malaise
-anorexia
± Burning, tingling
What are the symptoms of herpes simplex virus?
Painful rouped vesicles on erythematous base to ulceration / pustules / erosions with scalloped border
When is there resolution of herpes simplex virus?
Crusting and resolution within 2-6 weeks
What are orolabial lesions like in herpes simplex?
often asymptomatic
What is genital lesions like in herpes simplex?
often excruciatingly painful→ urinary retention
What are the systemic manifestations of herpes simplex?
aseptic meningitis in up to 10% of omen
What can causes reactivation of herpes simplex virus?
- spontaneous
- UV
- fever
- local tissue damage
- stress
What is eczema herpeticum, in herpes simlpex virus?
- emergency
- Monomorphic, punched out erosions (excoriated vesicles)
What is herpetic whitlow?
•HSV (1>2) infection of digits – pain, swelling and vesicles (vesicles may appear later)
What is the misdiagnosis of herpetic whitlow like?
- Misdiagnosed as paronychia or dactylitis
* Often in children
What is herpes gladiatorum?
- HSV 1 involvement of cutaneous site reflecting sites of contact with another athlete’s lesions
- Contact sports e.g. wrestling
When does neonatal HSV infection happen?
- Exposure to HSV during vaginal delivery – risk higher when HSV acquired near time of delivery
- HSV 1 or 2
What is the onset of neonatal HSV like?
- Onset from birth to 2 weeks
* Localised usually – scalp or trunk
What can happen in neonatal HSV?
- Vesicles → bullae erosions
* Encephalitis → mortality >50% without treatment, 15% with treatment → neurological deficits
What is the treatment of neonatal HSV?
IV antivirals
What are the types of HSV?
Severe or chronic
Who gets HSV?
Immunocompromised patients e.g. HIV / transplant recipient
What is the most common presentation of HSV?
- chronic, enlarging ulceration
- multiple sites or disseminated
What type of lesions are in HSV and what systems can be involved?
- Often atypical e.g. verrucous, exophytic or pustular lesions
- Involvement of respiratory or GI tracts may occur
What is the diagnosis of HSV?
Swab for Polymerase chain reaction
What is the treament of HSV?
•Don’t delay
- Oral valacyclovir or acyclovir 200mg five times daily in immunocompetent localised infection
- Intravenous 10mg/kg TDS X 7-19 days
What are the different types of varicella zoster virus?
Dermatomal
- Single dermatome
- Multidermatomal
- treat with iv antivirals
What causes hand foot and mouth disease?
- Coxsackie A16, Echo 71
- An acute self-limiting coxsackievirus infection
- Echo 71 (associated with a higher incidence of neurological involvement included fatal cases of encephalitis)
What are the symptoms of hand foot and mouth disease?
- Prodrome of fever, malaise, and sore throat
- Red macules, vesicles (typically gray and eliiptical), and ulcers develop on buccal mucosa, tongue, palate and pharynx, and may also develop on hands and feet (acral and volar surfaces).
How is hand foot and mouth disease spread?
direct contact via oral-oral route or oral faecal route
Which viruses cause morbilliform (measles-like) eruptions?
•Measles, Rubella, EBV, CMV, HHV6 & HHV7 cause morbilliform (measles-like) eruptions
What other agents cause morbilliform rashes?
- Leptospirosis
* Rickettsia
Which disorders mimic morbilliform eruptions?
- Drug eruptions (most commonly)
- Pityriasis Rosea
- Arthropod reactions
- Early guttate psoriasis
- Viral morbilliform reactions
What causes petechial/purpuric eruptions?
- Coagulation abnormalities - TTP, ITP, DIC
- Vasculitis
- Infections
- Viruses - Hepatitis B, CMV, Rubella, Yellow fever, Dengue fever, West nile virus
- Bacterial (BREN) - Borrelia, Rickettsia, Neisseria, Endocarditis
- Other infections - Plasmodium falciparum, Trichinella
- Other - TEN, Ergot poisoning, Raynauds
What is Gianotti-Crosti syndrome aka papular acrodermatitis of childhood?
viral eruption that causes and acute symmetrical erythematous papular eruption on face, extremities and buttocks – usually in children aged 1-3 years
What causes Gianotti-Crosti syndrome?
- EBV (most common)
- CMV
- HHV6
- Coxsackie viruses A16, B4 and B5
- Hepatitis B
What is another word for erythema infectiosum?
Parvovirus B19
What initially happens in erythema infectiosum?
mild fever and headache
What happens a few days later in erythema infectiosum
- A few days later – ‘slapped cheeks’ for 2-4 days
* Then reticulated (lacy) rash of chest and thighs in 2nd stage of disease
What is roseola infantum called?
exanthem subitum aka 6th disease
Who does roseola infantum affect and what are the first signs?
- Children
* 2-5 days of high fever
What are the signs of roseola infantum and how long does it last?
- Followed by appearance of small pale pink papules on the trunk and head
- Lasts hours to 2 days.
What causes roseola infantum?
HHV6 and HHV7 (less commonly)
What is Orf caused by?
parapoxvirus
When do people get Orf?
Direct exposure to sheep or goats
How does Orf present?
- Dome-shaped, firm bullae that develop an umbilicated crust.
- Usually develop on hands and forearms
How long does Orf last?
resolve without therapy in 4-6 weeks
