Title: GZ / The Grenz Zone Season 2 / 23 Viral Exanthems
Tags: GZ DermnetNZ

Q: [...] is the term used to describe a measles-like rash that consists of erythematous macules and papules that coalesce on the trunk, arms, and legs
A: Morbilliform
Back Extra: Think first of "bugs and drugs". Viral/bacterial infections in kids and meds in adults
The rash we see clinically in viral exanthems is due to the patient's immune response to that virus in the skin

Q: [...] refers to a rash on the skin surface, whereas [...] refers to changes on the mucous membranes
A: Exanthem; Enanthem

The 6 classic childhood exanthems are:
1st disease: Measles (Rubeola)
2nd disease: Scarlet Fever
3rd disease: Rubella (German measles)
4th disease: Duke's disease
5th disease: Parvovirus B19 (erythema infectiosum)
6th disease: Roseola Infantum

Measles(Rubeola) is transmitted via respiratory droplets and presents with a prodrome of fever & 4 "C's": cough, coryza, conjunctivitis, and Koplik spots followed by a morbilliform rash starts behind the ears and frontal hairline, spreading caudally a few days later
Back Extra: Recall the dreaded complication of measles: SSPE (subacute sclerosing panencephalitis). Occurs around 10 years after acute infection and presents with neuro sxs (seizures, coma, death)

Q: Rubella(German measles) has a mild/short 3 day course and presents with [palatal petechia] and more impressive lymphadenopathy than Rubeola
A: Forchheimer spots
Back Extra: Rare complication: Post-infectious encephalitis
Also a TORCH infection (may have vertical transmission from mother to baby)

Q: Erythema infectiosum(Slapped Cheek) is caused by [virus] and presents with a flu-like prodrome of fevers, headaches, myalgias, & small-joint arthralgias followed by the characteristic erythematous slapped cheek rash. 2-3 days later, a morbilliform eruption occurs that may have a [specific pattern]
A: Parvovirus B19; reticulate, lacy pattern
Back Extra: Recall, Parvovirus B19 is ssDNA. Most other DNA viruses are double-stranded

Q: Roseola infantum(Sixth Disease) presents in infants 6-12 months with high fevers [number] for up to 5 days while child does not appear to be very ill. This is followed by a faint, [specific color] morbilliform rash that favors the trunk and lasts a few days.
A: >102 F; rose-pink
Back Extra: Caused by HHV 6 & HHV 7 (HHV 6 & 7 also can cause Pityriasis Rosea)
Associated symptoms include: febrile seizures, upper respiratory sxs, lymphadenopathy, Nagayama's spots (red macules on soft palate and uvula)

What are the 7 Herpes Viral Infections?
HHV 1,2: Herpes simplex
HHV3: Varicella Zoster (VZV)
HHV4: Epstein-Barr (EBV)
HHV5: Cytomegalovirus (CMV)
HHV6: Roseola > Pityriasis Rosea
HHV7: Pityriasis Rosea > Roseola
HHV8: Kaposi sarcoma
Back Extra: HHV4 can also cause: Gianotti-Crosti syndrome, Oral hairy leukoplakia, Hydroa vacciniforme, Burkitt’s lymphoma, NK/T cell lymphoma
HHV8 can also cause: Castleman’s dz, primary effusion lymphoma (PEL)

Q: [...] is usually seen in pre-school age kids and presents with symmetric, monomorphous, pink-brown papules on face, buttocks, and extremities with relative sparing of the [body location]
A: Gianotti-Crosti Syndrome; trunk
Back Extra: Also known as papular acrodermatitis of childhood
Associated with EBV (HHV4)

What are 4 non-HHV's that can cause upper respiratory infections and viral exanthems?
Parainfluenza, Rhinovirus, Influenza A&B, Enterovirus (Coxsackie)

Q: Coxsackie A16 a.k.a. [common name] disease presents with a prodrome of fever, upper respiratory, and possibly GI sxs. They develop a vesicular eruption or erythematous macules on hands, feet, mouth, buttocks, and thighs
A: hand-foot-mouth
Back Extra: Very contagious. Hygiene is crucial to prevent spread

Q: A child with a morbilliform eruption localized to one axilla or inguinal crease has [...]
A: unilateral laterothoracic exanthem

Q: What are some viruses you should be thinking about in an adult who is sick enough to be in the hospital if you're suspicious for a viral cause? (5 viruses)
[...]
A: Dengue, Chikungunya, Zika, Mono (EBV), acute HIV