Viral Infections of Skin Flashcards
1
Q
skin rash decision tree
A
- infectious or not?
- if non-infectious-allergy, cancer, injury, AI?
- if infectious- bacterial, fungal, protozoan, viral?
- if viral-treatable or not?
2
Q
viruses that cause skin manifestations
A
-from most to least common: herpes- HSV1,2; VZV, EBV, CMV, HHV6,HHV7, KSH/HHSV8 coxsackie papilloma pox-molluscum, monkey, variola, vaccinia measles rubella
3
Q
sources of viral skin infections- exogenous
A
- from without
- infection at site of lesion
- breaks in skin integrity, cuts, insect bites, pimples
- mucous membranes
4
Q
sources of viral skin infections- endogenous
A
- from within
- disseminated infection
- viremia- spread through blood/lymph
- reactivation from latency
5
Q
dermatitis
A
- inflammation of skin
- non-infectious
6
Q
exanthem
A
- eruptive disease
- infectious rash
7
Q
macular/macule
A
-flat, discolored patch
8
Q
papular, papule
A
-raised, doscolored patch
9
Q
vesicular/vesicle
A
-raised, fluid filled blister
10
Q
petechial
A
=tiny dark spots due to localized hemorrhage
11
Q
pustular/pustule
A
-vesicle filled with pus
12
Q
umbilicated
A
pustule with dimple in center
13
Q
herpesvirus infections
A
- large, enveloped DNA viruses
- 8 different species
- most people infected with >3 kinds
- primary and recurrent infections
- a naive person is exposed and gets the disease through transmission
- secretions contain infectious viruses in primary or recurrent infections
- can also have asymptomatic shedding of virus
14
Q
primary HSV 1
A
- usually occurs in childhood
- stomatitis
- spread by close contact with active lesions or asymptomatic shedding
- lesions on mouth, face, nose, eyes
- latency in dorsal root ganglia
- usually above waist, can be genital
- trt with oral acyclovir or derivatives
- 50-80% of pop is seropositive
15
Q
recurrent HSV1
A
- herpes labialis
- cold sores
- 20% of seropositive people have recurrent lesions on lips, eyes, or inside mouth
- triggered by fever, UV exposure, hormones, stress, physical trauma
- trt with acyclovir, zovirax, valtrex, famvir
- use as needed for outbreaks or prophylactically to prevent recurrences
16
Q
HSV keratitis and corneal scarring
A
- primary infection of the eye often occurs at birth from vaginal mucosa
- caused by recurrence of HSV1 or 2
- chronic keratitis can cause corneal scarring and vision loss
- disease is mediated by infiltration of T cells that destroy cornea
- trt- antivirals to prevent corneal damage, corneal transplant may be needed
17
Q
herpetic whitlow
A
- primary HSV1 or 2 of non-mucosal sites, acquired by direct contact
- putting bare hands into others mouths is a risk factor
- dentists, hospital workers, and wrestlers are susceptible
- recurrences at unusual sites: hands, legs, back
- trt- acyclovir and derivatives
- prevention- gloves
18
Q
HSV2 primary
A
- genital herpes
- extensive vesicular, pustular or erythematous lesions on penis, labia, anus, oral and ocular possible
- other sx- pain, itching, fever, malaise, headache
- HSV2 usually but not always below the waist
- antiviral trt is important to shorten acute infection, prevent spread to brain
- double infections with HSV1/2 common
- highest risk for congenital infections from mother to fetus
19
Q
HSV2 recurrent
A
- recurrent genital herpes
- prodrome-itching, tingling at lesion site a day before outbreak
- vesicular lesions appear on labia, penis, anus, mouth
- lesions are contagious, shedding and transmission can also occur without sx, especially female to male
- freq of recurrences is highly individual, ranges from never to monthly
- prophylactic antiviral treatment can reduce recurrences and thus transmission
- infection is also emotionally painful, heavy stigma associated with HSV2
- moderate risk for perinatal infection
20
Q
Varicella-zoster virus primary
A
- chicken pox
- aerosol transmission, highly contagious
- 1-2 week incubation period: contagiousness, fever, malaise precede and accompany rash
- latency in dorsal root ganglia neurons
- distinctive rash- dew drops on rose petals; few to hundreds on face and trunk
- lesions are itchy, vesicular, form scabs that may scar
- trt and prevention-vaccine, acyclovir, foscarnet
- complications: visceral infections, dissemination to brain, bacterial infection of lesions
- severity increases with age
21
Q
VZV secondary
A
- herpes zoster/shingles
- prodrome-burning, itching, tingling
- outbreak occurs along a single dermatome
- vesicular lesions are extremely painful, pruritic
- more common in elderly and immunocompromised
- trt with acyclovir and derivatives
- complications include keratitis, retinitis, bell’s palsy, postherpetic neuralgia
- contagious to naive persons- can transmit virus and babies will get chicken pox
22
Q
herpes zoster ophthalmicus
A
- approx 30% of zoster outbreaks affect the face
- zoster in the eye can destroy the retina, rapidly leading to blindness
- all tissues of the eye can be infected and damaged
- long lasting pain is common
- treat aggressively
23
Q
VZV vaccines
A
- live attenuated virus
- varivax for varicella- ages 1-60, 80-90% effective
- zostavax for zoster, ages >50; 50% effective
- zostavax is 14 times higher dose than varivax
- ACIP recommends both
24
Q
EBV primary
A
- infectious mono
- EBV infects B cells and epithelia of oropharynx
- restricted to humans, 90% of population is infected by adulthood
- older teens have mono often
- 170,000 cases of infectious mono per year, 15 % hospitalized
25
EBV recurrences
- EBV is latent in a small fraction of B cells, most people are asymptomatic
- immune surveillance suppresses EBV
- recurrences linked to B cell cancers, esp in immunocompromised
26
oral hairy leukoplakia
- epithelial overgrowth caused by EBV
- non painful hairy/feathery lesions on tongue or buccal mucosa
- associated with HIV infections, transplants, chemo
27
CMV primary
- usually asymptomatic and acquired in childhood
- when sx do occur, similar to EBV
- lack of sore throat and presence of petechial rash and jaundice differentiate from EBV
28
roseola
- exanthem subitum
- caused by HHV6b and HHV7
- infect CD4 cells, also the site of latency
- transmitted by saliva
- by age 2, >90% of kids have had roseola tiwce
- 3 day illness- high fever followed by faint rash on trunk
- many infants are mistakenly given antibiotics for a suspected infection, then rash is attributed to drug allergy
29
kaposis sarcoma virus
- KSHV/HHV8
- primary infection has no known disease
- KSHV is prevalent in African, Mediterranean, and homosexual pops
- evidence for sexual transmission
- KSHV is found in B cells and endo cells, probable site of latency
- recurrences linked to cancers- kaposi's sarcoma, body cavity based lymphomas, castlemans diseasehyperplastic lymphadenopathy
30
coxsackie virus
- small naked ssRNA virus, enterovirus (with polio and others)
- herpangina-throat infection with red ringed blisters and ulcers on tongue/soft palate
- hemorrhagic conjunctivitis-begins as pain, then red, watery eyes with swelling, light sensitivity, and blurred vision
31
hand/foot/mouth disease
- painful blisters of the throat, tongue, gums, hard palate, inside of cheeks, and palms and soles
- common in pre school children and their parents
- highly contagious, spread on hands and surfaces contaminated with saliva and deces
- aerosol spread from sneezes/coughs
- no trt, prevent with hand washing
32
HPV
- small, naked DNA virus
- infects skin, genitals, cervix, anus,, mucosa
- spread by direct contact
- trt with chemical or surgical removal
- gardasil, vaccine for young women, now recommended for boys at age 11
- differentiate from lesions caused by molluscum contagiousum
33
molluscum contagiousum
- named after pearly appearance of vesicles, lack of IF
- poxvirus-large, enveloped DNA virus
- lesions are pearly, flesh colored, raised, imbilicated
- occur anywhere on body in kids
- anogenital area in sexually active adults
- occasionally, a single nodule may occur
- lesions rarely appear on palms, soles, mucosa, face or eyes
- transmission by skin-skin contact or fomites- tattooing, wrestling, towels
- disease incidence is 2-8%, most common in school aged kids
- higher incidence in HIV pop-5-20%
- trt-surgery, cryoptherapy, chemicals
- topical trt with cidofovir is promising
34
monkey pox
- indistinguishable from smallpox
- fatality rate 10-15%
- endemic to west and central africa
- squirrels are the natural host, disease occurs in monkeys and humans
- transmission via direct contact, aerosol, ingestion, needles, or person to person
- smallpox vaccine is cross protective
- # of human to human transmissions are increasing
35
variola virus
- smallpox
- historical cause of massive, lethal epidemics
- fever, severe aching pains, and prostration
- 2-3 days later, an umbilicated papular rash over face and extremities
- rash stages: papular, vesicular, then pustular, scabs leave pitted scars
- death usually occurs in the second week from overwhelming infections
- trt-supportive care and vaccination
- eradicated from the world in 1979 following vaccination
36
smallpox vaccine
- variola virus blended with other pox viruses to make vaccinia
- adverse reactions: live vaccine
- auto inoculation from arm to eye
- generalized vaccinia-virus disseminates in body
- eczema vaccinatum- not for people with eczema!
- progressive vaccinia- vaccinia necrosum or gangreosum- in immunocompromised patients
- trt is cidofovir and vaccinia immune globulin (VIG)
- still given to military, lab personnel, others who need protection
37
measles
- paramyxovirus, enveloped, negative strand RNA
- contagious during incubation process
- sx-cough, conjunctivitis, fever, rash
- spread through respiratory droplets
- kopliks spots- small red spots with bluish centers on buccal mucosa
- outbreaks in UK, Asia, Africa
- 122,000 deaths in 2013
- ~500,000 cases annually worldwide
38
rubella
- togavirus, enveloped pos strand RNA
- respiratory virus, aerosol spread
- maculopapular rash, lyphadenopathy, arthralgia
- congenital infections are severe
- no trt
- prevention-MMR vaccine- no association with autism, herd immunity is crucial to prevent outbreaks
39
other viruses
- many can cause rashes
- 5th disease (parvo), dengue, west nile, yellow fever
- many rashes look alike
- most viral exanthems look are never diagnoses
- offer supportive care, isolation if contagious
