Viral exanthems of childhood

What it is

The common childhood infections with exanthems are measles, rubella, mumps, varicella, fifth disease, roseola and scarlet fever. Each is read in four parts: the prodrome, the enanthem, the exanthem itself, and the complications. Rubella, also called German measles, is caused by the rubella virus, a rubivirus; roseola infantum, also called exanthem subitum, is caused by human herpes virus 6 and affects young children 6-36 months old; fifth disease is caused by human parvovirus B19. Rubella is also described as caused by the togavirus, and following the introduction of the MMR vaccine it is now rare.

How it presents

Measles, or rubeola, has a prodrome of cough, coryza, conjunctivitis and high fever, Koplik spots on the buccal mucosa as its enanthem, and macules that appear at the hairline, face and neck and spread cephalocaudally to the trunk and extremities over 3 days.

Rubella has mild constitutional symptoms: a low grade fever, sore throat, coryza and headache, with posterior auricular and posterior cervical lymphadenopathy. Its enanthem is Forchheimer spots on the soft palate, and its rash is erythematous, tender and maculopapular, begins on the face and spreads cephalocaudally, so it looks similar to measles. In contrast to measles, children with rubella often have only a low-grade fever and do not appear as ill.

Mumps has a prodrome of headache, fever, malaise and muscle pain, glandular swelling as its enanthem, and swollen parotid and submandibular glands.

Varicella has a prodrome of low-grade fever, malaise and URI symptoms, no enanthem, and crops of papules and vesicles with crusts at the same time, moving central to peripheral.

Fifth disease has mild URI symptoms, no enanthem, and a slapped cheek rash that moves to the trunk with central clearing and a lacy look.

Roseola has URI symptoms and abrupt high fever; the fever then falls rapidly and a fine macular rash appears. The rash starts on the neck and trunk and spreads to the extremities and the face.

Scarlet fever has a sore throat, an exudative pharyngitis with a strawberry tongue, and a fine maculopapular rash that feels like sand paper, especially in the antecubitus and inguinal areas, with Pastia lines. For rubella the incubation period is 14-21 days, and individuals are infectious from 7 days before symptoms appear to 4 days after the onset of the rash.

Hand-Foot-Mouth Disease belongs on this list and is known by where the vesicles are: a baby with poor feeding, vesicles in the mouth, on palms and soles, and a rash on the buttocks. The virus is Coxsackie virus A16. Set out as a scenario it is a toddler with fever, oral ulcers, vesicles on hands, feet and buttocks - so oral ulcers with a buttock rash in a toddler with poor feeding is the pattern to answer with.

The others are written the same way, as typical scenarios:

• Measles, rubeola: a 4-year-old with high fever, cough, coryza, conjunctivitis, then a maculopapular rash spreading head to toe, with Koplik spots inside the mouth. As a clue line: cough, runny nose, fever, then a macular rash that begins behind the ears and spreads down, with gray spots on the buccal mucosa.
• Rubella, German measles: a 6-year-old with low-grade fever, posterior auricular lymphadenopathy, and a rash spreading rapidly from face to trunk. As a clue line: sore throat, joint pain, fever, then a pinpoint rash on the face that spreads down, with rose spots on the palate.
• Roseola, HHV-6: a 9-month-old with high fever for 3 days, then a sudden rash as the fever resolves, pink macules on the trunk.
• Fifth disease, parvovirus B19: a 6-year-old with a slapped cheek rash, then a reticular rash on the body, often after a mild illness.
• Varicella, chickenpox: a 3-year-old with fever and a vesicular rash in different stages - papules, vesicles, crusts - starting on the trunk.
• Mumps: a 16 year old M with swollen parotid glands, fever and HA.