Viral Exanthems Flashcards
Define exanthem
- greek for breaking out
Define enanthem
- Rash of mucosa
Define Morbilliform
composed of erythematous macules & papules that resemble a measles rash”
Define centrifugal
rash that spreads from trunk to extremities
Define centripedal
rash that spread from extremities to trunk
When is a child immunized for measles?
- first dose: 12-15 months
2. Second dose: 4-6 years
How is measles described? what does the rash look like?
- Morbilliform rash- pathognomonic for measles
- Blanchable rash
- Facial exanthem is often confluent
- Appears sick or systemically ill (toxic)
How does measles spread?
Cephalocaudal extension*
What causes measles?
SS RNA virus of Paramyxoviridae family
Where is measles more prevalent? Who is at risk?
- More common developing countries*
2. Unvaccinated pop.
How is measles transmitted?
- Direct contact
- Airborne via aerosolized droplet nuclei
- Reportable disease
What is the pathophys of measles/rubeola?
- Incubation period: range 7-21 days
A. Ave. 10-12 days - Prodrome of 3-4 days
A. High fever (up to 105oF) that lasts 3-5 days
B. Classic triad (3 C s)
-Cough (nonproductive) can be “barking” cough
-Coryza
-Conjunctivitis: - Rash develops after prodrome
A. Typically about 14 days after exposure
B. Desquamation may occur afterwards
What is the classic triad of measles?
- Cough (nonproductive) can be “barking” cough
- Coryza: inflammation of nasal mucosa similar to rhinitis
- Conjunctivitis
What information do you need to obtain if measles is suspected?
- Vaccinated or not?
- Recent immigrants
- Migrant workers
- Travel history
- Immunosuppression/immunocompromised
What are the sxs of measles?
- Fever (103-105F)
- Malaise
- Photophobia
- 3 C’s
A. Cough
B. Coryza
C. Conjunctivitis - Koplik’s spots: preceed the rash
- +/- ear infection
What is a Koplik’s spot?
- Grainy white appearing area typically located near 2nd molars ““grains of salt on a wet background”
- Ulcerated mucosal lesions characterized by neutrophilic exudate and neovascularization.
What are the ddx for measles?
- Drug eruption
- Other viral exanthems
A. Rubella, parvovirus - Scarlet fever
- Kawasaki Syndrome
- Infectious Mono (EBV)
- RMSF
- HHV-6
What labs are ordered for measles?
- Measles-specific IgM
- Viral swab of throat, nasopharyngeal
- CBC w/diff
- +/- LP
How is measles treated?
- Isolation
- Vitamin A support
- Rest, Antipyretics, Antitussives
- Hydration
- Prevention: MMR
What complications can be present from measles?
1. Pneumonia A. Strep pneumoniae or Staph aureus B. Group A Strep C. immunocompromised patients 2. Otitis media 3. Encephalitis
How long is a child with measles contagious?
4 days before rash till 4 days after the rash
How is rubella described? What does the rash look like?
- 3 day measles
- Pinpoint pink maculopapules
A. 1st on face, spreads caudally to trunk/extr & generalized w/in 24 hrs
B. w/in 1 day rash fades from face -> centrifugal spread: trunk to extrem.
C. Pink macules coalesce on trunk but remain discrete on extrem
How is rubella different from rubeola?
- Rubella is less red, more benign dz, spreads more quickly
What is the etiology of rubella?
Rubella virus, togavirus RNA virus
How is rubella transmitted?
Contaminated nasal airborne respiratory droplets
What is the pathophys of rubella?
- Virus invades respiratory epithelium
- Spreads to bloodstream
- Disseminates to skin
What is the dz process of rubella?
- 14-21 days
2. Onset of rash is usually day 15
When are rubella pts contagious?
infected pts may shed virus and are potentially contagious for 1-2 wks before infection is clinically apparent
What are the sxs of rubella in children?
- Children – little to no prodrome
2. Mild conjunctivitis, HA, adenopathy, low-grade fever (100.9 F)
What are the sxs of rubella in adolescents?
- HA
- Malaise
- Anorexia
- Arthralgias
What are the genreal signs of rubella?
1. Forschheimer’s spots (20%) A. Red petechiae on soft palate B. During prodrome phase 2. Lymphadenopathy A. Postauricular B. Suboccipital C. Post. Cervical 3. Possible splenomegaly
What are the ddx for rubella?
Drug eruptions Other viral exanthems Scarlet Fever Acute Rheumatic Fever Measles
What labs will be performed for rubella?
- Viral cultures
Throat - Rubella-specific IgM antibody: diagnostic
- Acute phase: leukopenia with lymphocytosis
What is the major complication for rubella?
1. If mom is unvaccinated and gets rubella A. Congenital rubella syndrome (CRS) -Hearing loss, deafness -Mental retardation -CV defects -Ocular defects -Cataracts -Hydrocephalus
What are the contraindications to MMRV?
- pregnancy and immunocompromised patients
- Pregnant women are screened for rubella and syphilis at 1st prenatal visit
A. can get IgG and IgM
How is rubella treated?
- Supportive
- Isolation
- Antipyretics
- Hydration
- Prevention: Prevention: MMR vaccine: 97% effective after single dose
How is scarlet fever’s rash described?
- Fine erythematous papular rash 1st on trunk
A. Sandpaper texture
B. Blanches - Involves neck, trunk, axilla, extremities
- No facial rash typically
What is the etiology of scarlet fever?
- Group A Beta hemolytic Strep pyogenes (GAS)
2. Exotoxin producing Staph aureus (rare)
How is scarlet fever transmitted?
- Direct contact with infected patient
- Direct contact with carrier
- Site of GAS infection: pharynx, tonsils
What are the complications of GAS tonsillopharungitis?
- Nonsuppurative:
A. Acute Glomerular Nephritis, rheumatic fever, strep toxic shock syndrome - Suppurative: pus, purulent, otitis media, sinusitis, tonsillar abscess
What is the incubation period for scarlet fever?
2-5 days
What is the pathophys of scarlet fever?
- Rash due to exotoxin from bacteria
2. Possible hypersensitivity reaction