Viral Exanthams

Question 1

Macule

Answer 1

<1 cm
Circular
Flat
Discolouration (red, brown, blue)

Question 2

Papule

Answer 2

<0.5 cm
Superficial
Solid
Elevated
Color varies

Question 3

Morbilliform

Answer 3

Erythematous macules and papules

Resembles measles

Question 4

Vesicle

Answer 4

<1 cm

Circular collection of fluid

Question 5

Pustule

Answer 5

Vesicle containing pus

Question 6

Petechiae (petechial)

Answer 6

Pinpoint
Round spots
As a result of bleeding

Question 7

Exanthem

Answer 7

A rash that appears abruptly and affects several areas of the skin simultaneously
Viral ones are more common in children, nonspecific, and self limiting

Question 8

Measles virus

enveloped?, nucleic acid, family, genus, causes what, transmission

Answer 8

Enveloped non-segmented ssRNA (-)
Family Paramyxoviridae, genus Morbillivirus
Causes measles (rubeola): infection of the respiratory tract, spreads and presents as a morbilliform rash
Highly contagious
Spread by aerosol and contact

Question 9

R naught

Answer 9

Average number of people that one sick person will infect

Measles has a very high R0 (18)

Question 10

Symptoms of Measles (rubeola)

Answer 10

Fever
The 3 C’s: cough, coryza, conjunctivitis
Koplik spots in the mouth
Morbilliform rash: generalized, maculopapular, erythematous

Question 11

Complications of measles

Answer 11

Bronchitis
Pneumonia
Encephalitis
Death
SSPE (Subacute sclerosing panencephalitis)

Question 12

Subacute sclerosing panencephalitis

Answer 12

Rare progressive neurological disorder
Can occur years after measles infection
Even if the person is fully recovered from the illness
Death usually within 3 years

Question 13

Molecular detection of measles

Answer 13

Respiratory illness but spreads to areas including the bladder
RT-PCR from nasopharyngeal swabs, throat, and urine
RT-PCR more sensitive than IgM
Viremia before rash appears

Question 14

Rubella Virus

enveloped?, nucleic acid, family, genus, transmission, causes what, detection

Answer 14

Enveloped, ssRNA (+)
Family: Togaviridae, genus: Rubivirus
Tranmission droplet and vertical
Adult disease is a self limiting rash
Concern is infection during pregnancy: congenital rubella syndrome, miscarriage or severe birth defects
MMR vaccination!
Serology is useful, also PCR

Question 15

Congenital Rubella Syndrome

Answer 15

Child contracted rubella from the mother in utero
Outcomes: deafness, cataracts in the eyes, heart problems, meningoencephalitis, mental or growth retardation, enlarged liver and spleen, skin lesions, bleeding problems

Question 16

Parovirus B19

enveloped?, nucleic acid, family, genus, transmission, causes what

Answer 16

Non-enveloped ssDNA
Parvoviridae family, Erythrovirus genus
Transmission droplet and vertical
Infectious period before the onset of rash
Causes erythema infectiosum

Question 17

Erythema infectiosum

Answer 17

Prodrome: low-grade fever, malaise, headache, coryza, myalgias, joint pain (more common in adults)
Exanthem: begins with bright red ceeks, then get a symmertric, erythematous, reticular eruption on trunk and extremities
Usually mild for children and adults
Can lead to aplastic crisis
Treat with blood transfusion

Question 18

Hydrops fetalis

Answer 18

Fetal anemia can lead tot his

Intrauterine growth retardation, pleural/pericardial effusions, and death

Question 19

Roseola infanticum (exanthema subitum)
(enveloped?, nucleic acid, transmission, symptoms)

Answer 19

Human herpesvirus 6 or 7
Enveloped, dsDNA
Transmission unknown, but likely droplet and contact
No vaccine, infection leads to immunity
Immunocompromised have significant mortality
Rash: papular purpuric gloves and socks syndrome, purple or brownish red spots, usually in adolescents

Question 20

Enterovirus

family, enveloped?, nucleic acid, transmission, causes what

Answer 20

Picornaviridae family
Non-enveloped, ssRNA (+)
Transmission: droplet, contact
Respiratory, CNS and exanthems
Hand foot and mouth disease (skin and oral lesions resembling canker sores)
Seasonal: common in late summer and early fall

Question 21

Hand foot and mouth disease

Answer 21

From enteroviruses, echoviruses, and coxsackie viruses
Rash starts in the mouth and resembles canker sores
Later presents on hands and feet (bring pink macules and papules, then painful vesicles and erosions with erythema, usually self limiting and resolves within days)

Question 22

Varicella zoster virus

enveloped?, nucleic acid, family, transmission, symptoms

Answer 22

Enveloped dsDNA
Family: herpesviridae
Human herpes virus 3
Transmission: aerosols
Vaccines available
Contagious for a couple days before rash
Rapid progression from macules to papules to vesicles with crusting

Question 23

Complications of varicella

Answer 23

Bacterial infections in children (skin and soft tissue)
Severe pneumonia (adults)
Septicemia
Necrotizing faciitis
Septic arthritis
Hemorrhagic conditions
CNS infection/encephalitis
Zoster in children

Question 24

Herpes Zoster

Answer 24

Painful vesicular eruption in a dermatomal distribution
From VZV reactivation
Disseminated zoster spans more than one dermatome, in immunocompromised people

Question 25

Diagnosis for herpes zoster

Answer 25

PCR is highly sensitive and specific

Serology (only for immunity)

Question 26

Herpes zoster treatment

Answer 26

Antivirals: acyclovir, cidofovir, foscarnet

VZIG (immunoglobulin): exposed neonate or susceptible adult

Question 27

2 VZV vaccines

Answer 27

Varivax (chickenpox vaccine): childhood vaccination programs

Zostavax (shingles vaccine): reduces severitiy and occurances of PHN