Infectious Exanthems Flashcards
DNA viruses
HPV - warts Pox virus - MC, smallpox (Variola) Orf virus - Exanthem contagiosum Herpes (varicella, HSV1/2, HHV 6/7, EBV) Parvovirus - erythema infectiosum (Fifth disease)
RNA viruses
Enterovirus (Coxsackievirus - HFM, Echo virus - non-specific, EV D68 - severe respiratory) Paramyxovirus - measles (rubeola) Togavirus - rubella arbovirus - dengue virus, chikungunya Filoviridae - ebola
exanthem
expressed on cutaneous surfaces
enanthem
expressed on mucosal surfaces
HPV –>
common warts, plantar warts, flat warts, genital warts, condylomata
HPV transmission
person to person by contact or through fomites
non-seasonal
HPV incubation
3 months to many years
HPV management
liquid N2, various acids, laser, surgical, laser
prevention
Small growth on surface of skin and gradually enlarges over long period. Relatively few sxs (maybe pain on foot). Small black dots seen centrally. Surface exhibits hyperkeratinization.
HPV - wart
Asymptomatic discrete papular waxy lesions gradually develop on surface of skin. Umbilicated appearance. 2-20 in generalized location
Molluscum contagiosum (poxvirus)
Molluscum contagiosum spread
humans - direct contact/fomites
non-seasonal
infectivity low
MC incubation
2-7weeks to 6 months
MC management
mechanical removal
liquid N2, acids
Vesiculated rash from distal distribution to central
HA, fever, malaise, muscular pains before rash
Rash develops in same stages w/ local crops and becomes encrusted. Illness lasts 2 weeks and resolves w/ significant scarring. Hemorrhagic form is highly fatal
Variola (smallpox) - poxvirus
Variola transmission
direct contact w/ skin lesions, mucous membranes
human transmission
animals in winter/spring
incubation smallpox
12 days
communicability of smallpox
onset of rash - clearing of crusts
dx of smallpox
culture of lesions, serology
smallpox management
strict isolation, symptomatic tx, active immunization
eczema vaccinatum
skin reaction - underlying skin disease + smallpox vaccine
Sheep herder (spring) notices small pimple on finger. No other sxs.
Ecthyma contagiosum, orf (poxvirus)
orf virus transmission
working with sheep - zoonosis usually seen in spring
directly from infected animal
incubation orf virus
4-7days
dx of orf
solitary lesion on hand, beginning as erythematous papule and developing into a vesicle
management of orf
duration is usually 30-40 days
spontaneously resolves w/ only symptomatic care
wear gloves
General malaise - fever - pruritic rash beginning centrally on head and trunk and extending peripherally.
Macule –> papule in 24 hrs
Local areas have various stages of development
Clears over week to 10 days
Latent infection, do not treat w/ aspirin (Reye’s)
varicella (chickenpox)
Herpes virus - VZV
VZV transmission
exposure to nasopharyngeal droplet, skin lesion contact, easily air spread
Peaks in late winter/spring
VZV incubations
14-16 days
VZV communicability
1-2 days before rash to when rash begins to crust (5 days)
VZV dx
clinical inspection of rash, spreading from macule to vesicles in 24 hours, hx of contact, immunofluorescence stain of lesion, serology
vzv management
strict isolation, avoid use of aspirin, avoid hospitalization, vitamin a, immunization
oral acyclovir w/in 24 hrs
smallpox vs chickenpox
smallpox ill 7-17 days after contact has fever/malaise 2-4 days before rash Pocks mostly on face/arms/legs Present on palms/soles Scabs 10-14 days after rash appears Fall off 14-28 days after rash appears
Chickenpox
ill 14-21 days after contact
no sxs before rash
pocks most numerous on body, not on palms/soles usually
Scabs 4-7 days after rash appears
scabs fall off w’/in 14 days after rash begins
Stinging erythematous lesion at junction skin/lip
Proceeds to crusted sore over few days but lasts up to 10-12 days. no systemic sxs noted.
Lesions of oral cavity (gingiva and tongue) and genital region may be found
Herpes simplex 1 and 2
HSV1/2 transmission
direct contact - sexual and birthing contacts
non-seasonal but associated w/ stress
HSV1/2 incubation
varies from 2d-2w, becomes latent and recurs
HSV1/2 communicability
not well defined, 1 to several weeks
dx of HSV1/2
clinical picture, recovery from lesion for cell culture, fluorescent antibody