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Viral Exanthems

Terms in this set (84)

What are Exanthems?


What are Enanthems?
Exanthem--SKIN rashes caused by viral infections



Enanthem--Lesions that occur on MUCOSAL surfaces
What is a maculopapular rash?
A mix of macules and papules
**What is crucial for the diagnosis of Viral Exanthems?
**The pattern of illness is more important than the appearance of the rash
Rash begins on the extremities and spreads towards the trunk
Centripetal
Rash that spreads from the trunk to the extremities
Centrifugal
Which are maculopapular and which are vesicular rashes?
Measles (rubeola)
German measles (rubella)
Coxasackieviruses
Scarlet fever (S. pyogenes)
Herpes simplex (HSV)
Erythema infectiosum (Fifth disease, parvovirus B19)
Chickenpox (varicella, VZV)
Roseola infantum (human herpesvirus 6, HHV6)
Maculopapular:
Measles (rubeola)
German measles (rubella)
Scarlet fever (S. pyogenes)
Erythema infectiosum (Fifth disease, parvovirus B19)
Roseola infantum (human herpesvirus 6, HHV6)

Vesicular:
Coxasackieviruses
Chickenpox (varicella, VZV)
Herpes simplex (HSV)
What kind of virus is Measles?


What does it naturally occur in?
Paramyxovirus



Humans only! No animal reservoirs (what else is like this?)



(smallpox)
Does measles usually affect adults or children?



What seasons does measles occur?
Childhood illness




Winter and Spring
What cells does the measles virus infect? How does it end up as a rash?
The measles virus infects epithelial cells of respiratory tract and spreads by viremia to the reticuloendothelial system. There is then a secondary viremia that leads to the rash.
Where can the measles virus replicate?
Conjunctiva, respiratory tract, GI, GU, lymphatic system, blood vessel and the CNS
What is the histology of measles?
Multinucleated giant cells seen in skin and mucosa
Are measles contagious?


How are measles transmitted?
Yes, HIGHLY contagious


Measles are spread by DROPLETS of infected nasopharyngeal secretions
When are individuals with measles contagious?
Individuals are contagious for 7 days before the rash till 1-2 days after the rash appears

They are most contagious BEFORE the rash appears
A prodromal illness includes Koplik's spots for this disease



What are Koplik's spots? Are they exanthems or enanthems?
Measles!!




Koplik's spots are ENANTHEMS that are typically found on the buccal and labial mucosa. They are irregular areas of patchy erythema with a central, minute bluish-white speck with the appearance of a "grain of salt"
A morbilliform (maculopapular) rash
Measles!!
What is the measles rash caused by?
T-cell response to virus-infected cells lining capillaries
Where does the measles rash usually begin and how does it spread?
It begins on the FACE and spread over 3-4 days to involve trunk and limbs.
-Can involve the palms and soles
-Becomes confluent extensive
When does the measles rash start to fade? What's up with the skin when the rash starts to fade?
It fades in 72 hours.

It can leave post-imflammatory pigmentation that may take 6-8 weeks to fade
How is diagnosis for Meales usually made?


What are other ways to make a diagnosis?
Clinically


See a leukopenia, see IgM in serum, or see 4x increase in IgG titer in paired (acute and convalescent) sera.
What is the treatment for measles?
NO antiviral therapy!
What can decrease the severity of measles?
Vitamin A
What kind of vaccine is the Measles vaccine? Who can't be given this vaccine?


What are side effects of this vaccine?
Live-attenuated vaccine
Immunocompromised can't get this vaccine


Side effects: Mild fever, mild rash
When is the MMR vaccine administered?
15 months, and then again between 4-6 years old
Togavirus
Rubella (German measles)
Who gets Togavirus?
What seasons is it seen?
CHILDREN get rubella

Seen in the winter and spring
Only occurs in humans
Rubella
Smallpox
How is Rubella transmitted? What else is like this?
Nasal DROPLET spread

Like Measles!
What Viral exanthem causes lymphadenopathy?
Rubella
Where does Rubella replicate and then spread to?
Rubella replicates in the UPPER RESPIRATORY TRACT and spreads to the LYMPH NODES, causing lymphadenopathy
What happens after the prodromal illness of fever, malaise and anorexia in Rubella?
Maculopapular rash
What is Rubella rash like?
Maculopapular rash that spreads from top to bottom
-not usually Confluent (unlike measles)
Suboccipital and postauricular lymphadenopathy is useful for diagnosis of
Rubella (Togavirus-German Measles)
When does viral shedding of rubella continue to?
2 weeks after the start of the rash
What are the complications of Rubella?
-Arthritis of the small joints in 1/3 of women
-Hemorrhagic complications, including thrombocytopenia
-Encephalitis
-Congenital Rubella syndome
How is Congenital Rubella Syndrome acquired?
It is acquired in babies if there is an acute infection while the non-immune mother is pregnant
When is the fetus at highest risk for Congenital Rubella Syndrome?
EARLY in pregnancy, up until the 20th weeks of gestation
65-85% in the first 2 months
What are the illnesses that are associated with Congenital Rubella Syndrome?


How long may the virus persist in an infant's eye? When can the virus be shed?
-Deafness
-Cataracts or glaucoma
-Congenital Heart disease


The virus may persist for 3-4 years and may be shed up to 1 year after birth
How is a diagnosis of Rubella made?
Clinical diagnosis and serology. Look for rubella-specific IgM or a 4-fold increase in IgG on paired sera
When is the Rubella vaccine administered?


When is it advised NOT to be vaccinated for rubella?
Like measles! First time at 15 months, and then again between 4-6 years old



Don't get vaccinated DURING PREGNANCY because there is waning of the immune system
What is Scarlet Fever caused by?

What are the major illnesses from Scarlet fever?
Caused by S. pyogenes! (Group A Strep)


Major illnesses: FEVER & RASH
What does confluent mean, according to Afsoon?
Background of erythema
What do certain strains of Strep pyogenes produce that actually cause the fever in Scarlet fever?
Erythrogenic toxin (pyrogenic toxin)
Who is scarlet fever usually seen in?
Children between 1-10
How to differentiate between Scarlet Fever and Parvovirus?
Most cases of Scarlet Fever are associated with pharyngitis (pus on the tonsils)
-Scarlet Fever has a STRAWBERRY TONGUE
LONG incubation period
Rubella
SANDPAPER-like rash
Scarlet Fever
Where are the rashes concentrated in Scarlet Fever?

What body part especially?
In the SKIN FOLDS!

Especially the antecubital fossa
Desquammation
Scarlet Fever
How do you treat Scarlet Fever?
Anti-streptococcal antibiotics
Respiratory transmission
Measles
Rubella
Parvovirus
What seasons do you usually see Parvovirus?
Winter/spring

(like Measles and Rubella!)
Arthritis seen in Women
Complication of Rubella
Parvovirus
What are the clinical syndromes of Parvovirus?
-Erythema Infectiosum
-Acute arthritis in adults
-TRANSIENT aplastic crisis in patients with rapid red cell turnover
-Chronic anemia (Pure Red Cell Aplasia) in IMMUNODEFICIENT
-Fetal demis
Slapped cheeks
Erythema Infectiosum (Fifth Disease)
How does the rash in Erythema Infectiosum progress?
Slapped cheek first, then a LACY Reticular Rash on the Trunk and Extremities
How do you make a diagnosis for Erythema Infectiosum?
Serology (Check for IgM or Increase in IgG)
Why can you not check serology for immunocompromised patients with Pure Red Cell Aplasia? Whay do you use instead?
They cannot make antibodies to Parvovirus! Must do a PCR for Parvovirus DNA in the blood!
Giant pronormoblasts found in the bone marrow
Parvovirus
What is Roseola Infantum caused by?
HHV6 (Human Herpes Virus)
Who is Roseola Infantum usually seen in?
Children -- Roseola INFANTum (get it, infant?!)
How is Roseola Infantum spread?
Contact with SALIVA
What seasons are Roseola Infantum seen in?
Spring/Fall

(Different than measles, rubella and parvovirus!)
ABRUPT fever! And once the fever resolves a pink macular rash appears
Roseola Infantum -- (ROSEola--pink rose!)
What blood findings do you see with Roseola Infantum?
Drop in WBC (Leucopenia)
Atypical lymphocytes in the bone marrow
How severe is Roseola Infantum?
Very mild. Most patients won't even go to seek attention. Self-limited disease.
How can you make a diagnosis for Roseola Infantum?


What is the treatment?
Clincal! But can also do serologic testing



Treatment is supportive
What seasons are Enteroviruses seen in?
DIFFERENT:
Summer/Early fall
What age groups does Enterovirus affect?
DIFFERENT:
Affects ALL ages (not just children like most of the other viral exanthems)
How are enteroviruses spread?
Fecal-oral, or respiratory
What causes Hand-Foot-and-Mouth syndrome?
Coxsackievirus A16
Kids with this will stop eating because they have so many sores on their mouth that are so tender
Hand-Foot-and-Mouth syndrome
Vesicle ENANthem on buccal mucosa or tongue that can ulcerate
Hand-Foot-and-Mouth syndrome
Do the exanthems from Hand-Foot-and-Mouth syndrome hurt?
YES, the exanthems may be TENDER
Where are the papules from Hand-Foot-and-Mouth syndrome located?
Hand
Geet
Proximal Extremities
Buttocks
How are the exanthems from Hand-Foot-and-Mouth syndrome different than Measles or Rubella?
The exanthems do NOT evolve to form pustules or scabs
What season is Herpangina seen in?
DIFFERENT: Summer
Does herpangina cause exanthems or enanthems? Where?
ENANthems, usually in the posterior pharynx (soft palate and tonsillar pillars) and RAPIDLY ULCERATES
What is herpangina caused by?
Coxsackievirus
Herpangina presents exactly like this other disease?
Oral herpes
How are Hand-Foot-and-Mouth disease and Herpangina different than the other exanthems?
These two are VESICULAR
What spreads VERY rapidly?
Meningococcemia
Rash characterized by central clearing
Erythema Chronicum Migrans (Lyme Disease)
Patient is DIFFUSELY red, like a lobster. No papules. Hypotensive. Skin will blanch
Toxic Shock Syndrome caused by Staph and Strep
Lacy rash, not caused by Parvovirus
Vasculitis
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