Viral Exanthems
Fever + Rash
● Decreased incidence in sri lanka due to immunization.
● But not eradicated.
● Examples- measles(morbillivirus)
Rubella (rubella virus)
Chicken pox (varicella)
Roseola (herpes virus 6B)
Erythema infectiosum (parvovirus B19)
Infectious mononucleosis (Epstein barr virus)
● Exanthems also can caused by bacterial infections,
Staphylococcal toxin infections-
Toxic shock syndrome
Staphylococcal scalded skin syndrome
Streptococcal toxin infections-
Scarlet fever
Streptococcal toxic shock-like syndrome
● Measles
1. RNA virus
2. Infants acquire immunity- transplacental immunity — lasts for 4–6 months.
3. Highly contagious.
4. Dissemination of the virus will occur at the catarrhal stage.
5. 4 stages,
I. Incubation phase- no symptoms (10–12 days)
II. Prodormal phase- fever, cough( hoarse, dry) , runny nose, conjunctivitis, tightening in chest, koplik’s spots
III. Rash- at the highest of fever, macular papular , non itchy spread to face, trunk and then to limbs very rapidly.
IV. Recovery phase- fine flaking of the skin, rash fades(10–14 days after the rash)
(koplik’s spots- 1–2 days before the rash, in buccal mucosa, near the molar teeth)
● Diagnosis is mostly clinical.
● Complications
I. Pneumonia
II. Otitis media
III. Diarrhea
IV. Encephalitis
V. Myocarditis — infrequent
VI. Sub acute sclerosing encephalitis(SSPE)- rarely
● Sub acute sclerosing encephalitis(SSPE)
Rare, fatal form of degenerative encephalitis develops an average of 5–10 years after a typical case of measles. Non contagious. Gradual onset, results in behavioral changes and impairment of intellectual function leading to seizures, repetitive myoclonic jerks, cerebellar ataxia, retinopathy, rigid spastic with decorticate posture, coma and death. Survive 1–3 years after diagnosis. EEG, CT and MRI helps in diagnosis.
● Rubella
RNA virus, Contagious
Rash +/-
Cervical, post auricular, occipital nodes are usually involved
Usually a mild and frequently inapparent infectious disease in children and adults.
Rubella infection during the first trimester of pregnancy can result in,
Miscarriage
Stillbirth
Congenital rubella syndrome in infants
Features of Congenital rubella syndrome,
Cataract, retinopathy, microphthalmia
Sensorineural deafness
Congenital heart disease- pulmonary stenosis, PDA
Hepatospleenomegaly, CP, epilepsy
● Chicken pox
Mild compared to adults
Rash- Papules->vesicles->crust
Small itchy blisters. Usually starts on the chest, back and face, then spreads to the rest of the body.
The disease is often more severe in adults than children. In pediatrics rarely get complications. So Acyclovir is not used routinely
● Complications
o Cerebellar ataxia
o Pneumonia
o Post viral encephalitis
o Haemorrhage chickenpox
o Bacterial skin infections
● Fifth disease/ erythema infectiosum
Parvovirus B19
Clinical features- high temperature
Bright red cheeks (slapped cheek appearance)
Flat or raised red rash, lasts from 2–39 days and may itch. The rash fades from the centre of the red areas toward the edges, giving it a lacy appearance
The disease is usually mild, but in certain risk groups it can have serious complications.
Infection in the 1st trimester of pregnancy has been linked to hydrops fetalis, causing spontaneous miscarriage.
In sickle cell disease or other forms of chronic hemolytic anemia such as hereditary spherocytosis, infection can precipitate an aplastic crisis.
