Derm - Viral Exanthemas

Question 1

What is an exanthem?

Answer 1

Eruptive widespread rash

Question 2

What are the 6 viral exanthemas?

Answer 2

First disease : Measles

Second disease : Scarlet Fever

Third disease : Rubella

Fourth disease : Duke’s Disease

Fifth disease : Parvovirus B19

Sixth disease : Roseola Infantum

Question 3

What causes measles?

Answer 3

Measles virus

Highly contagious

Question 4

How does measles present?

Answer 4

10-12 days after exposure with fever, coryzal symptoms and conjunctivitis

Koplik spots
Greyish white spots on buccal mucosa, appears 2 days after fever

Rash starts on face behind ears, 3-5 days after fever then spreads to rest of the body

NOTIFIABLE DISEASE - PUBLIC HEALTH

Question 5

What does the rash in measles look like?

Answer 5

Erythematous, macular rash with flat lesions

Question 6

How long does measles take to resolve?

Answer 6

7-10 days of symptoms

Question 7

How long should children be isolated for after symptoms resolve?

Answer 7

4 days

Question 8

What are the complications of measles?

Answer 8

30% develop complications

Pneumonia
Diarrhoea
Dehydration
Encephalitis
Meningitis
Hearing loss
Vision loss
Death

Question 9

What is Scarlet fever caused by?

Answer 9

Exotoxin produced by streptococcus pyogenes bacteria

Associated with group A streptococcus usually tonsilitis - not caused by a virus

Question 10

What is scarlet fever characterised by?

Answer 10

Red-pink, blotchy, macular rash with rough sandpaper skin that starts on trunk and spreads outwards

Red, flushed cheeks

Strawberry tongue

Question 11

What are the features of scarlet fever?

Answer 11

Strawberry tongue
Cervical lymphadenopathy

Flushed face

Red-pink, blotchy macular rash
Lethargy
Extremely rough, sandpaper skin
Throat, sore

Fever

Question 12

How is scarlet fever treated?

Answer 12

Phenoxymethylpenicillin (Penicillin V) for 10 days

For underlying streptococcal infection

NOTIFIABLE DISEASE- PUBLIC HEALTH

Question 13

How long should children be off school for after antibiotics?

Answer 13

24 hours after starting antibiotics

Question 14

What other conditions are associated with group A strep infection?

Answer 14

Post-streptococcal glomerulonephritis
Acute rheumatic fever

Question 15

What is rubella caused by?

Answer 15

Rubella virous

Highly contagious

Question 16

How is rubella spread?

Answer 16

Respiratory droplets

Symptoms start 2 weeks after exposure

Question 17

How does rubella present?

Answer 17

Milder erythematous macular rash vs measles

Rash starts on the face and spreads to the rest of the body
Mild fever
Joint pain
Sore throat
Lymphadenopathy behind ears and back of neck

Question 18

How long does the rash last in rubella?

Answer 18

3 days

Question 19

How is rubella managed?

Answer 19

Supportive
Condition is self-limiting

NOTIFIABLE TO PUBLIC HEALTH

Question 20

How long should children be kept off school in rubella?

Answer 20

At least 5 days after the rash appears

Question 21

What are the potential complications of rubella?

Answer 21

Thrombocytopenia
Encephalitis

Question 22

Who in particular should be avoided in patients with rubella?

Answer 22

Pregnant women

Question 23

Why is rubella so dangerous in pregnancy?

Answer 23

Can cause congenital rubella syndrome

Triad of :
- Deafness
- Blindness
- Congenital heart disease

Question 24

What is Duke’s disease and is it still diagnosed?

Answer 24

AKA fourth disease

No longer diagnosed as was used to describe non-specific viral rashes

Question 25

What is Parvovirus B19 disease?

Answer 25

AKA fifth disease, slapped cheek syndrome and erythema infectiosum Caused by Parvovirus B19 virus

Question 26

How does parvovirus B19 present?

Answer 26

Mild fever Coryza Muscle aches Lethargy After 2-5 days bright red rash on both cheeks **slapped cheeks** After a few days a reticular (net-like) mild erythematous rash affects trunk and limbs, can be raised and itchy

Question 27

How is parvovirus B19 managed?

Answer 27

Self-limiting Rash and symptoms fade over 1-2 weeks Supportive management with plenty of fluids and simple analgesia

Question 28

When should children with parvovirus B19 be kept off school?

Answer 28

Infection prior to rash formation After rash formation they are no longer infectious

Question 29

What are some potential complications of parvovirus B19?

Answer 29

**Aplastic anaemia** Encephalitis or meningitis Pregnancy complications- foetal death **Rarely** Hepatitis, myocarditis or nephritis

Question 30

What patients are at risk of complications of parvovirus B19?

Answer 30

Immunocompromised Pregnant women Sickle cell Thalassaemia Hereditary spherocytosis Haemolytic anaemia

Question 31

How are patients at risk of complications of parvovirus B19 checked?

Answer 31

Serology testing to confirm diagnosis FBC and reticulocyte count for aplastic anaemia

Question 32

What is Roseola Infantum?

Answer 32

AKA roseola or sixth disease Caused by human herpesvirus 6 and rarely human herpesvirus 7

Question 33

What is the typical pattern of roseola infantum?

Answer 33

**High fever** 1-2 weeks after infection Comes on suddenly lasting for 3-5 days and then disappears suddenly May be coryzal symptoms, sore throat and swollen lymph nodes When the fever settles, rash appears for 1-2 days

Question 34

How does the rash appear in roseola infantum?

Answer 34

Mild erythematous macular rash across arms, legs, trunk and face **Not itchy**

Question 35

How long do children have to stay at home with roseola infantum?

Answer 35

Generally no need to be kept off nursery if well enough to attend Full recovery within a week

Question 36

What is the main complication of roseola infantum?

Answer 36

**Febrile convulsions** Due to high temperature

Question 37

What are immunocompromised patients with roseola at rare risk of?

Answer 37

Myocarditis Thrombocytopenia Guillain-Barre syndrome