Micro U2 L6. Flashcards
What are the viruses in order from most to least common that cause skin manifestations?
Herpesviruses, Coxsackie virus, papilloma virus, poxvirus, measles, rubella
dermatitis
inflammation of the skin, non infectious
exanthem
an eruptive disease, infectious RASH
macular, macule
flat, discolored patch
papular, papule
raised, discolored patch
vesicular, vesicle
raised, fluid filled blister
erythema, erythematous
redness
petechial, petechiae
tiny, dark spots due to localized hemorrhage
pruritic, pruritis
itchy
pustular, pustule
vesicle filled with pus
umbilicated
pustule with dimple (umbilicous) in center
Herpesvirus
large, enveloped DNA viruses, 8 species, most people with 3+ - establish latency in neurons or lymphocytes during primary infection - infection by secretions and mucous membranes
Primary Herpes simplex virus type 1
-usually in childhood by close contact - lesions on mouth, face, nose, eyes - latency in dorsal root ganglia - usually above waste
Recurrent HSV-1
herpes labialis (cold sores) - recurrences triggered by fever, UV exposure, hormones, stress, physical trauma - contagious
Treatment for HSV-1
oral acyclovir
HSV keratitis
primary infection in the eye often occurs at birth from vaginal mucosa - caused by recurrence of HSV-1 or 2 - can cause corneal scarring and vision loss - mediated by infiltration of T cells that destroy the cornea
Treatment for HSV keratitis
antivirals to prevent corneal damage - corneal transplant may be needed
Herpetic Whitlow
primary HSV-1 or 2 of non-mucosal sites - acquired by direct contact - usually by dentists, hospital workers, wrestlers - recurrences in unusual sites (Hands, legs, back) - prevent with gloves
HSV-2
genital herpes - extensive vesicular, pustular, erythematous lesions on penis, labia, anus - can also have pain, itching, fever, malaise, headache
Recurrent genital herpes
prodrome: itching, tingling at lesion site a day before outbreak - lesions are contagious, but transmission can occur without symptoms
Varicella-zoster virus
HSV 3 - chicken pox (varicella) - latency in neurons of dorsal root ganglia where it can reactivate along the dermatome to cause shingles (zoster)
Varicella rash
“dew drops on a rose petal” - few to hundreds on face and trunk - itch, vesicular, form scabs - 1-2 week incubation
Varicella treatment/prevention
varivax vaccine (live attenuated) - acyclovir and foscarnet
VZV (varicella) recurrence
herpes zoster - prodrome: burning, itching, tingling - outbreak along single dermatome - painful and pruritic vesicular lesion
Zoster vaccine
zostavax (only 50% effective)
HZO: herpes zoster ophthalmicus
30% zoster outbreaks affect face - zoster in eye can destroy retina causing blindness
EBV: primary infectious mononucleosis
infects B cells and epithelia of oropharynx - 90% of population by adulthood - childhood infections often asymptomatic - NO RASH
EBV recurrences
latent in small fraction of B cells - most people asymptomatic - recurrences linked to B cell cancers esp in immunocompromised
Oral hair leukoplakia
epithelial overgrowth caused by EBV - non painful hairy or feathery lesions on the tongue or buccal mucosa - associated with immunosuppressed - no treatment :(
Cytomegalovirus
usually asymptomatic, childhood - when there are symptoms - similar to IM caused by EBV
How are cytomegalovirus and EBV symptoms distinguished?
EBV has lack of sore throat and presence of petechial rash and jaundice (IM has no rash!!)
Roseola: Exanthem subitum
HHV6b and 7 - infect CD4 cells - site of latency - transmitted in saliva. 90% of children have had it twice by age 2
Roseola rash
3 day illness of high fever followed by a faint rash on the trunk - no antibiotics because that may cause a rash too
Kaposi’s sarcoma
HHV8 - no known disease with primary infection. prevalent in african, mediterranean, homosexual populations (maybe sexual) - found in B cell and endothelial cells (latency?)
KSHV recurrence
linked to cancer esp kaposi’s sarcoma - body cavity-based lymphomas
Coxsackie virus
RNA virus - enteroviridae
Skin manifestations of coxsackie
herpangina: throat infection causes red-ringed blisters and ulcers on tonsils and soft palate AND hemorrhage conjunctivitis: begins as eye pain, then red, watery eyes with swelling, light sensitivity, blurred vision
Hand, foot and mouth disease
painful red blisters in throat, tongue, gums, hard palate, inside of cheeks, and palms of hands and soles of feet (coxsackie virus) - spread on hands and surfaces contaminated by poop and saliva
Human papilloma virus
small, naked DNA virus - infects skin, genitals, cervix, anus, mucosa - spread by direct contact
Poxvirus skin rash
small pox! - others are MCV and monkey pox
MCV - molluscum vontagiousum virus
pearly appearance of the vesicles - lack of inflammation = pale and shiny also UMBILICATE - by skin-skin contact or by fomites (tatooing, wrestling, towels) - most common in children - need physical removal
Monkey Pox
indistinguishable from small pox - fatality 10-15%, endemic to west and central africa - natural host squirrels with disease in humans and monkeys - transmission by direct contact, aerosol, ingestion, needles, person-person -> protected by small pox vaccine
Variola virus
small pox! - lethal epidemics - fever, severe aching pains and prostration - umbilicate papular rash over face and extremities - death week 2 from overwhelming infection
Vaccina virus
smallpox vaccination (blend of variola and other poxviruses) - LIVE vaccine
Measles virus
paramyxovirus, enveloped, negative strand RNA - contagious during incubation period - cough, conjunctivitis, fever, rash
Measles rash
Kopliks’ - small red spots with bluish centers on buccal mucosa
Rubella virus
togavirus, enveloped, postive strand RNA - respiratory virus, aerosol spread - congenital infections severe
Rubella rash
maculopapular rash, lymphadenopathy, arthralgia
