Exanthems

Question 1

Define exanthem

Answer 1

• widespread rash
• usually in children
• toxins, drug, microbes, autoimmune

Question 2

Three exanthems we will study

Answer 2

• Erythema infectiosum (Fifth disease)
• Hand, Foot, Mouth disease
• measles

Question 3

Erythema infectiosum

• aka
• causative organism
• timing
• incubation
• transmission

Answer 3

• aka Fifth disease
• caused by Parvovirus B19**
• late winter/early spring
• incubation 4-14 days
• respiratory route, aerosolized droplets

Question 4

Erythema infectiosum

- clinical findings in children

Answer 4

• MC asx
• nonspecific sx: HA, coryza, low-grade fever
• pharyngitis, malaise, myalgias, diarrhea, nausea, cough, conjunctivitis
• 10% arthralgia or arthritis, lrg joints

Question 5

Erythema infectiosum

- rash specific clinical findings

Answer 5

• begins with confluent, erythematous, edematous plaques on cheeks “slapped cheek”
• fades 1-4 days
• then pink to erythematous macule or papules on trunk, neck, extensor surfaces
• lesions have central fading = reticulated appearance
• usually no pruritus
• lasts 5-9 days, can recur with triggers (sunlight, exercise, temp change, bath, emotional stress)

Question 6

Erythema infectiosum

- adult clinical findings

Answer 6

• acute arthropathy is primary finding (MC women)
• symmetric polyarthritis of small joints (hand, knee)
• self-limiting
• can persist/recur for months
• constitutional sx more severe than in children
• Fever, adenopathy, mild arthritis w/o rash most common
• rash if present: reticulated on extremities, rarely slapped cheek

Question 7

Erythema infectiosum

- dx

Answer 7

• based on clinical findings
• labs usually normal
• IgM anti-HPVB19 antibodies or IgG seroconversion or PCR for B19 DNA possible

Question 8

Erythema infectiosum

- major complications (2)

Answer 8

• Transient aplastic crisis

- Fetal B19 infection

Question 9

Erythema infectiosum

- Transient aplastic crisis

Answer 9

• cessation of RBCs
• MC cause in patients with chronic hemolytic anemia
• fatigue, pallor, worsening anemia

Question 10

Erythema infectiosum

- Fetal B19 infection

Answer 10

• **spontaneous abortion (first half)
• **hydrops fetalis (fluid in compartments like lung or brain)
• late fetal death
• congenital anemia

Question 11

Erythema infectiosum

- treatment

Answer 11

• none, usually not needed
• supportive therapy for fatigue, malaise, pruritus, arthralgia
• offer serologic B19 testing to pregnant women exposed to B19 (follow with frequent US)

Question 12

Hand-Foot-and-Mouth Disease

• demographics
• timing
• transmission
• pathogen

Answer 12

• Children <10 MC
• summer and fall
• highly contagious
• oral-oral and fecal-oral
• Coxsackievirus A16 and enterovirus 71

Question 13

Hand-Foot-and-Mouth Disease

- clinical findings

Answer 13

• first: low-grade fever, malaise, abd pain, URI sx
• nearly all: painful oral lesions on tongue, buccal mucosa, hard palate
• later: 2/3 get cutaneous lesions on hand, feet, buttocks (occasionally genitalia, face, legs)
• red macule and papules > vesicle with red halo > crust/erosion

Question 14

Hand-Foot-and-Mouth Disease

- diagnosis

Answer 14

• clinical dx

- no labs

Question 15

Hand-Foot-and-Mouth Disease

- tx

Answer 15

self-limiting in 7-10 days

- supportive tx only

Question 16

Hand-Foot-and-Mouth Disease

- complication

Answer 16

• aseptic meningitis

Question 17

Measles

• aka
• transmission
• timing

Answer 17

• rubeola
• highly contagious, respiratory droplets
• contagious several days before onset of rash and up to 5 days after lesions appear
• winter and spring
• Immunization greatly reduces incidence

Question 18

Measles

- clinical presentation

Answer 18

prodrome
- high fever, malaise, conjunctivitis, coryza, cough. May last up to 4 days
Exanthem:
- 4th febrile day
- erythematous, non-pruritic macs/paps on forehead at hairline and behind ears
- spreads centrifugally and inferiorly to face, trunk, extremities, palms/soles
- reaches feet by day 3
- resolves in 4-6 days

Question 19

Measles

- Enanthem

Answer 19

• cluster of tiny bluish-white spots on red background
• **Koplik spots: on buccal mucosa opposite premolar teeth
• on or after second day of febrile illness

Question 20

Measles

- other sx

Answer 20

• vomiting
• diarrhea
• abd pain
• splenomegaly
• pharyngitis
• otitis media
• generalized lymphadenopathy

Question 21

Measles

- dx

Answer 21

Clinical suspicion, confirm via serology:

• MC: measles-specific IgM antibody and measles RNA via PCR
• obtain both serum sample and throat swab
• higher prob of detection if collect respiratory and urine samples

Question 22

Measles

- complications

Answer 22

• MC <5 yo and >20 yo
• **pneumonia (MC in children)
• otitis media
• laryngotracheobronchitis
• diarrhea
• acute encephalitis (perm brain damage)
• subacute sclerosing panencephalitis - rare but fatal, can develop 7-10 years after measles infection

Question 23

measles

- tx

Answer 23

• primarily supportive
• maintain good hydration
• transmission precautions for 4 days after rash onset
• tx secondary bacterial infections with abx
• Severe case tx with vitamin A (dz can lead to vitamin A deficiency)
• People exposed should receive prophylactic immunoglobulin prophylaxis within 6 days of exposure