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
What are the sxs of scarlet fever?
Sore throat Headache Myalgias Nausea / Vomiting Cough Diarrhea Fever Strawberry tongue Punctate petechiae palate Pastia’s lines Sandpaper rash Desquamation On body and extr when exanthem fades
What are pastia’s lines?
Exacerbation in skin folds:
antecub., popliteal fossa, axilla, groin
What are the ddx of scarlet fever?
- Staph or Strep TSS
- Kawasaki’s Syndrome
- Viral exanthems
- Drug eruption
What labs are performed for scarlet fever?
- Rapid Strep Ag test
- Throat cx (TC)
- ASO titer (inc.)
What is the treatment for scarlet fever?
- Penicillin V 250-500 mg po BID-TID x 10 days- DOC
- Amoxicillin 50 mg/kg/day po divided doses x 10 days
A. Erythromycin/Azithromycin/Clarithromycin/Cephalexin: If allergy to penicillin - Supportive Care
What is the rash asst. with rheumatic fever?
erythema marginatum
How is roseola described?
- Exanthem Subitum
- Generalized fine MacularPapular rash
A. Small blanchable
B. Starts behind ears
C. Spreads to trunk - Usually course of infection is benign self-limited w/ rare sequelae
What is the etiology of roseola?
- Human herpes virus type 6 (HHV-6)
A. Most common - Human herpes virus type 7 (HHV-7)
A. 10-30%
How is roseola transmitted?
Oropharyngeal secretions
What is the incubation period for roseola?
5-15 days
What age group most commonly gets roseola?
6-36 months
What are the sxs for roseola?
1. High fever x 3-5 days* A. 38.9 – 40.6C B. 103 – 105F 2. Rash appears when fever breaks (4th day) 3. Toxic appearance 4. LAD, TM’s red
What is the ddx for roseola?
- Other viral exanthems
- Consider drug allergy when child with fever tx w/ abx
then develops rash (a lot of times pruritic)
What labs are performed for roseola?
- Seldom necessary
2. HHV6 & HHV7 Ab titers
How is roseola treated?
- Treatment is supportive care:
A. Hydration
B. Antipyretics: Acetaminophen
What are the complications of roseola?
Febrile seizures possibly
True false: roseola is contagious?
False: Not considered contagious
Describe eryhtema infectiosum (fifth disease)
- Edematous erythematous plaques on cheeks
- “Slapped cheeks”
- Lacy reticulated rash trunk & extremities (stocking/glove)
What is the etiology of fifth dz?
Parvovirus B19
Who gets fifth dz?
School-aged children, although adults too
How is fifth dz transmitted?
- Respiratory via droplet aerosol
- Perinatally
- Exposure to classmates or siblings
What is the incubation period for fifth dz?
4-14 days
What are the sxs of fifth dz?
Nonspecific prodrome: Fever Malaise HA Coryza Mild Conjunctivitis Diarrhea 2 days prior to rash Slapped cheeks” appearance Lacy erythematous rash on trunk & ext* Often pruritic May recur with intermittent rash over 2-3 weeks
What are the ddx for fifth dz?
Roseola Rubella Measles Enteroviral inf GAS inf Drug Eruption
What are the complications for 5th dz?
- Arthritis*
- Hemolytic Anemia
A. Sickle Cell
B. Thalassemia - Fetal death or hydrops fetalis
A. 20 wks: rar
What labs are performed for 5th dz?
- HPV B19 IgM Ab
2. B19 DNA using NAAT (nucleaic acid amplification test)
What is the treatment for 5th dz?
Symptomatic
How is varicella-zoster virus described?
- Systemic illness
2. Successive crops of pruritic vesicles that evolve to pustules, crusts and at times scarring
Who gets chicken pox?
90% cases children
What is the etiology of vzv?
VZV DNA virus
How is vzv transmitted?
- Direct contact
2. Airborne droplets
What is the incubation period for vzv?
14 days (10-23 days) from contact
What is the pathophys of vzv?
- Virus enters mucosa respiratory tract
- Viral replication
- Viremia
- Dissemination to skin
- Skin to sensory nerves to sensory ganglia to latent infection
What are the prodrome characteristics of vzv?
- HA, myalgias
- Malaise, low-grade fever
- Pharyngitis
- Loss of appetite
When does the vzv rash appear? What does it look like?
- Generalized vesicular rash usually w/in 24 hrs
- Papules to vesicles to pustules to crusts
- “Dewdrops on a rose petal”
- Cephalocaudal spread
What are the ddx for vzv?
- Disseminated HSV
2. Enterovirus infection
What labs are performed for vzv?
- Tzanck prep.- cytology of fluid or scraping of vesicles show giant and multinucleated epidermal cells
- VZV titers
- Diagnosis usually made on clinical findings alone*
How is vzv treated?
- Symptomatic
A. No aspirin - Acyclovir if severe
What complications can appear in children
- S aureus or Group A Strep Superinfection
- Varicella encephalitis
- Reye’s Syndrome: encephalopathy w/ liver dysfunction
What complications can appear in adults from vzv?
In adults:
A. VZV encephalitis
B. Pneumonia
C. VZV hepatitis in immunocompromised pts
How is vzv prevented?
- VZV vaccination (Varivax) 1995
2. MMRV
Describe impetigo
- Superficial infection of epidermis
- Crusted erosions
A. Golden-yellow, stuck-on), honey-crusted - Two types
A. Non-bullous
B. Bullous
What is the etiology of impetigo?
- S. aureus
A. Most common with bullous - GAS (Strep pyogenes)
A. Most common with non-bullous
How is impetigo transmitted?
Bacteria enters through breaks in skin (non-bullous)
What is the pathophys of non-bullous impetigo?
Non-bullous -
Bacteria in epidermis causes vesicles or pustules leading to erosions and crusting
What is the pathophys of bullous impetigo?
Eruption occurs in non-traumatized skin via exfoliating toxin
What are the sxs of impetigo?
- Variable pruritis
- Erythema
- Crusted lesions
- Bullous lesions
- Regional lymphadenopathy possible
What are the ddx for impetigo?
- Excoriation
- Perioral dermatitis
- Seborrhea dermatitis
- Allergic contact dermatitis
- HSV
What labs are performed for impetigo?
Gram stain or Culture lesions but usually clinical dx
What is the treatment for impetigo?
- Mupirocin ointment 2% (Bactroban) Apply topically TID x 7-10 days
- Cephalexin (Keflex) - 1st choice for oral therapy
What are the complications of impetigo?
- Cellulitis
- Bacteremia
- Septicemia
What is another name for coxsackie virus?
Hand, Foot & Mouth Disease (HFMD)
How is HFMD described?
- Systemic infection
- Ulcerative oral lesions
- Vesicular exanthem on distal extremities
- Usually children
A.
What is HFMD caused by?
- Most Common
A. Coxsackie Virus A16 - Enterovirus A71
A. More severe
How is HFMD transmitted?
- Direct Contact
A. Highly contagious
B. Oral-Oral route
C. Oral-Fecal route
What is the incubation period for HFMD?
3-5 days
What is the pathophys for HFMD?
- Enteroviral implantation in GI tract
- Extends to regional lymph nodes
- Viremia
- Oral lesions, skin lesions
What is the dx process for HFMD?
- Illness usually resolves in 2-3 days w/o complication
2. Most contagious during first week
What are the sxs for HFMD?
- Anorexia
- Low grade fever
- Sore mouth
- Possible URI sxs
- Prodrome 12-24 hrs of low-grade fever, malaise, abd pain or resp sxs
- Painful ulcerative oral lesions
- Refusal to eat
- Skin lesions on palms and soles come together or shortly after oral lesions
A. Macules, papules ->vesicles
Define herpangina
Oral enanthem caused by Coxsackie A virus
What are the ddx for HFMD of only oral lesions are present?
- HSV infection
- Herpangina
- Adverse drug rxn
- Sudden outbreak of oral and distal ext. lesions is pathognomonic for HFMD
What labs are performed for HFMD?
- Viral cultures from vesicles or throat
2. Stool/rectal swabs
What is the treatment for HFMD?
- Supportive
2. Lidocaine/xylocaine gel
What complications can arise from HFMD?
- Myocarditis
- Aseptic meningitis (enterovirus )
- Encephalitis
- Pulmonary edema
- Above uncommon