Merck Manual

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Some Viral Infections in Children That Cause a Rash

Some Viral Infections in Children That Cause a Rash

Infection

Period of Incubation

Period of Contagiousness

Site of Rash

Nature of Rash

Measles (rubeola)

7 to 14 days

From 2 to 4 days before the rash appears until 2 to 5 days after

Starts around the ears and on the face and neck

Spreads to the trunk, arms, and legs

Begins 3 to 5 days after the start of fever, runny nose, cough, red eyes, and sore throat and lasts 3 to 5 days

Irregular, flat, red areas that soon become raised

Rubella (German measles)

14 to 21 days

From a week before the rash appears until a week after it appears

Infected newborns are usually contagious for many months

Starts on the face and neck

Spreads to the trunk, arms, and legs

Begins 1 or 2 days after the start of mild fever, swollen and tender lymph nodes, red eyes, and headache and lasts 3 to 5 days

Fine, pinkish, flat rash

Roseola infantum (exanthem subitum or pseudorubella)

About 5 to 15 days

Unknown

Starts on the trunk and usually spreads to the neck, face, arms, and legs

Begins on about the 4th day after the start of a high fever and usually just when the fever ends and lasts for hours to a few days

Pinkish red, flat or raised rash

Erythema infectiosum (fifth disease or parvovirus B19 infection)

4 to 14 days

From before the start of the rash until 1 to 2 days after

Starts on the cheeks

Spreads to the arms, legs, and trunk

Begins several days after the start of low fever, headache, and runny nose and lasts 5 to 10 days

May recur for several weeks

Red rash on the cheeks (slapped-cheek rash) spreads to the arms, legs, and trunk and becomes lighter and blotchy with lacy patterns

Chickenpox (varicella)

11 to 15 days

From a few days before the start of symptoms until all spots have crusted

Starts on the face, neck, and trunk

Spreads to the arms, legs, and scalp

Appears in crops, so various stages are present simultaneously

Begins shortly after the start of fever and feeling of illness and lasts a few days to 2 weeks

Small, flat, red spots that become raised and form round, fluid-filled blisters against a red background before finally crusting