viral infections of skin

Question 1

what are the viral skin manifestations listed in order from most common to least?

Answer 1

Herpesviruses, coxsackie virus, HPV, poxviruses, measles and rubella

Question 2

what are the sources of viral skin infections?

Answer 2

exogenous (from the environment) or endogeneous (from disseminated infection)

Question 3

how do viruses infect the skin?

Answer 3

through breaks in skin integrity or mucous membranes

Question 4

what are the endogenous causes of viral skin infection?

Answer 4

viremia or reactivation from latency

Question 5

define dermatitis.

Answer 5

inflammation of the skin

Question 6

what is exanthem?

Answer 6

an eruptive disease (infectious rash)

Question 7

define macular, papular and vesicular.

Answer 7

macular is a flat discoloration, papular is a raised patch, vesicular is a raised, fluid filled blister

Question 8

define erythema and petechiae

Answer 8

erythema is redness. petechiae are tiny dark spots due to localized hemorrhage

Question 9

what is pruritis?

Answer 9

itching

Question 10

what is a pustule? what does umbilicated mean?

Answer 10

a vesicle filled with pus. it is umbilicated if it has a dimple in the center

Question 11

what type of virus are herpesviruses? how common are they?

Answer 11

large enveloped DNA viruses. most people are infected with greater than three kinds

Question 12

how are herpesviruses transmitted?

Answer 12

by secretions and mucous membranes of an infected individual with primary or recurrence of a latent infection. asymptomatic shedding also occurs

Question 13

where do herpesviruses establish latency?

Answer 13

in neurons or lymphocytes during primary infection

Question 14

describe primary HSV 1. who does it infect?

Answer 14

usually in childhood. lesions on mouth and face (usually above the waist)

Question 15

where does HSV 1 latency occur? how is it treated and how common is it?

Answer 15

in dorsal root ganglia
treat with oral acyclovir
50-80% of population is infected

Question 16

what are some common names of recurrent HSV1? what percentage of people have recurrence

Answer 16

cold sores, canker sores or fever blisters

20% of people have recurrent lesions

Question 17

what triggers HSV 1 recurrence? what is the treatment?

Answer 17

fever, UV exposure, hormones, stress and physical trauma

treat with acyclovir, zovirax, valtrex and famvir as needed or prophylactically

Question 18

which herpesviruses cause keratitis and corneal scarring? when does primary infection occur? what causes the damage?

Answer 18

HSV 1 and 2
primary infection occurs at birth from vaginal mucosa
caused by infiltration of T cells into the cornea

Question 19

what is herpetic whitlow? how is it treated?

Answer 19

primary HSV 1 or 2 on nonmucosal sites. risk factor is putting bare hands into people’s mouths. treat with acyclovir

Question 20

describe primary HSV 2 lesions.

Answer 20

extensive vesicular, pustular and erythematous lesions on penis, labia, anus and possibly oral areas. accompanied by itching, fever malaise and headache

Question 21

why is antiviral treatment important for primary HSV 2 lesions?

Answer 21

to shorten the acute infection and prevent spread to the brain (meningial involvement indicated by malaise and headache)

Question 22

describe recurrent HSV2 lesions. why is treatment important?

Answer 22

prodrome accompanied by vesicular lesions. frequency is variable and prophylactic antiviral can reduce recurrences and transmission.

Question 23

what is the risk for perinatal and congenital infection with HSV2?

Answer 23

most risk during primary infection congenitally. moderate risk for perinatal infection with recurrence

Question 24

what is the primary infection of vericella zoster virus? where is it latent and what is the recurrence?

Answer 24

chicken pox

latent in dorsal root gangial neurons and recurrs as shingles

Question 25

how is varicella transmitted? describe the rash and symptoms

Answer 25

aerosol transmission | fever and malaise precede and accompany rash of dew drops on rose petals on face and trunk (itchy)

Question 26

what are the complications of varicella?

Answer 26

visceral infection, dissemination to the brain, penumonitis and bacterial infection of lesions (increases in severity with age of primary infection)

Question 27

how is varicella treated?

Answer 27

prevented with varivax (vaccine) and treated with acyclovir and foscarnet

Question 28

describe herpes zoster.

Answer 28

prodrome followed by outbreak of vesicular, painful lesions on a single dermitome. more common in elderly and immunocompromised

Question 29

how is zoster treated? what are the possible complications?

Answer 29

acyclovir | keratitis, retinitis, bells palsy and postherpetic neuralgia

Question 30

what is herpes zoster opthalmicus? which tissue are effected? how is it treated?

Answer 30

shingles in the eye that can destroy the retina. effects all tissues of the eye and long lasting pain is common. treat aggressively with acyclovir and IV foscarnet

Question 31

describe the VZV vaccines. what kinds are there and at what doses?

Answer 31

live attenuated virus varivax- prevent varicella (80-90% effective) zostavax prevents zoster (give >50, 50% effective) zostavas has 14 times higher dose than varivax

Question 32

what illness does epstein barr virus cause? who does it infect? what cells?

Answer 32

causes mononucleosis, infects most people in childhood. infects the B cells and the epithelia of the oropharynx

Question 33

where is EBV latent? what recurrences does it cause?

Answer 33

latent in the B cells. recurrences are linked to B cell cancers especially in the immunocompromised. (oral hairy leukoplakia)

Question 34

who does cytomegalovirus infect? what are the symptoms?

Answer 34

infects children with mononucleosis similar to EBV. There is no sore throat and there is a petechial rash and jaundice

Question 35

what viruses cause roseola? what cells does it infect?

Answer 35

HHV6b and HHV7 | infects CD4 T cells (also site of latency)

Question 36

how is roseola transmitted? what are the symptoms? how is it often treated?

Answer 36

saliva three day high fever followed by a faint rash on the trunk children given antibiotics mistakenly and the rash is presumed to be an allergy to the antibiotic

Question 37

what virus causes kaposis sarcoma? where is it prevalent and what cells does it infect?

Answer 37

HHV8 prevalent in Africa, the mediterranean population infects B cells and endothelial cells (site of latency)

Question 38

what other cancers are associated with HHV8?

Answer 38

body cavity based lymphomas and castleman's disease (hyperplastic lymphadenopathy)

Question 39

what is the morphology of coxsackie virus?

Answer 39

small, naked ssRNA virus of the enterovirus family

Question 40

what are the skin manifestations of coxsackie virus?

Answer 40

herpangina- throat infection with red ringed blisters and ulcers on the tonsils and soft palate hemorrhagic conjunctivitis- eye pain with red, watery eyes, light sensitivity and blurred vision

Question 41

what is hand, foot and mouth disease?

Answer 41

presentation of coxsackie virus with painful blisters in the mouth, on the palms and soles of the feet. common in preschool aged children and their parents

Question 42

how is coxsackie spread? how is it treated?

Answer 42

spread on hands and surfaces contaminated by feces and saliva. also aerosolized no treatment

Question 43

what is the morphology of HPV and where does it infect?

Answer 43

small, naked DNA virus | infects skin, genitals, cervix, anus and mucosa

Question 44

how is HPV spread? how is it treated?

Answer 44

spread with direct contact treat with chemical or surgical removal prevent with gardasil

Question 45

what are the three pox viruses? why are they becoming more of a problem?

Answer 45

molluscum contagasiosum, monkey pox and smallpox | more of a problem because the smallpox vaccine is no longer being given which protected against monkey pox

Question 46

describe the appearance of molluscum contagiosum virus. where do they appear?

Answer 46

pearly appearing vesicle that is umbilicated without inflammation. found anywhere on the body (except face, mucosa, palms and soles) in children and on anogenital area in sexually active adults

Question 47

who is commonly affected by molluscum contagiosum virus?

Answer 47

school aged children and HIV positive population

Question 48

how is molluscum contagiosum virus treated?

Answer 48

with cidofovir. remove with surgery, cryotherapy or chemicals (recurs if "popped")

Question 49

where does monkey pox occur and how is it transmitted?

Answer 49

in west and central africa squirrels are the natural host and it also infects monkeys. transmitted through contact, aerosol, ingestion, needles or person to person

Question 50

what virus causes smallpox? what are the symptoms?

Answer 50

variola virus | fever, severe aching pains and prostration. umbilicated papular rash over face and extremities. death in second week

Question 51

how is smallpox treated?

Answer 51

supportive care and vaccination. eradicated from the wild with worldwide vaccination

Question 52

what virus is included in the smallpox vaccine?

Answer 52

vaccinia virus- mixture of variola and other poxviruses. live attenuated vaccine

Question 53

what are the possible complications from smallpox vaccine?

Answer 53

autoinnoculation of the eyes, generalized dissemination in the body, eczema vaccinatum (contraindicated for people with eczema), and progressive vaccinia (necrosis and gangrene in immunocompromised patients) all are recoverable except the last

Question 54

what is the morphology of measles virus? why does it spread so easily?

Answer 54

paramyxovirus enveloped with negative strand RNA | infectious during the incubation period

Question 55

what are the symptoms of measles virus?

Answer 55

cough, conjunctivitis, fever and rash (small red spots with bluish centers in mouth called koplik's spots)

Question 56

what is the morphology of rubella virus?

Answer 56

togavirus, enveloped with positive strand RNA

Question 57

how is rubella sperad? what are the symptoms?

Answer 57

aerosol spread | maculopapular rash, lymphadenopathy and arthralgia (worse if congenital)