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Viral exanthem in childhood

Viral exanthem

Papular rashes

  • Molluscum contagiosum – papular rash
    • Definition
      • Viral pediatric dermatological infection caused by DNA poxvirus through transmission by direct skin contact, autoinoculation (scratching lesions) and fomites, mainly affecting children under the age of 5 and early adolescence
    • Epidemiology
      • Children under the age of 5 and early teens
    • Incubation period
      • 1 week to 6 months
    • Presentation
      • Unlike many of the rashes discussed on this page, there are usually no other systemic symptoms or flu or cold like symptoms
      • Non-tender, typically skin colored dome shaped papules with central umbilication are found on the face, trunk and extremities
    • Diagnosis
      • Clinical diagnosis
    • Treatment
      • Self-limiting, typically no treatment is necessary as lesions disappear within 6 months to 1 year
      • Cryotherapy can be performed

Maculopapular rashes

  • Roseola infantum – maculopapular rash
    • Definition
      • Viral pediatric rash caused by HHV-6 (rarely HHV-7) that is transmitted through droplets affecting children between 6 months and 3 years
    • Epidemiology
      • Between 6 months and 3 years
    • Incubation period
      • 10-14 days
    • Clinical presentation
      • Febrile phase
        • Duration: 3-5 days
        • Main features
          • High fever (may trigger febrile seizures)
          • Rhinitis and cough
          • Irritability
        • Other features
          • Lymphadenopathy (cervical, postauricular, occipital)
          • Inflamed ear drum
          • Nagayama spots – papular enanthem on uvula and soft palate
          • Vomiting
          • Diarrhea
          • Conjunctivitis
          • Edema of eyelid
      • Exanthem (rash) phase
        • Duration: 2-3 days
        • Abrupt drop in temperature followed by patchy maculopapular exanthem
          • Originates on the trunk, can spread to face, arms and legs
          • Rosy color that is blanchable
          • Nonprurtic
    • Diagnosis
      • Clinical diagnosis
    • Treatment
      • Symptom management
      • Self-limiting disease
  • Fifth disease (erythema infectiosum) – maculopapular rash
    • Definition
      • Viral pediatric rash caused human parvovirus B19 infection transmitted by droplets affecting mostly children between ages 6-10
    • Epidemiology
      • Peak between 6-10 years in children
    • Incubation period
      • 10-17 days
    • Presentation
      • Prodromal phase
        • Flu-like symptoms including fever, for 2-5 days before rash
      • Exanthem phase
        • Distinctive red rash on both cheeks (slapped cheek syndrome)
        • Spreads to trunk and extremities
        • Lasts for 7-10 days
        • Rash may reoccur with sunlight or heat exposure for several weeks
      • In rare cases it may result in arthritis or anemia as well which may last for weeks
    • Diagnosis
      • Clinical diagnosis in young immunocompetent children
      • Serology can identify parvovirus B19-specific IgM antibodies
    • Treatment
      • Self-limiting disease
      • Symptom management
Fifth disease.jpg
  • Measles – maculopapular rash
    • Definition
      • Viral rash caused by morbillivirus that is transmitted through direct contact of droplets affecting mostly children under the age of 12
    • Epidemiology
      • Peaks under the age of 12
    • Incubation period
      • 9-14 days
    • Presentation
      • Prodromal phase
        • Duration
          • 4-7 days
        • Fever
        • 3 C’s of cold like symptoms
          • Cough
          • Conjunctivitis
          • Coryza (rhinorrhea, congested nose)
        • Koplik spots (pathognomonic for measles)
          • Small white papules, with a central blue-white area found on the buccal mucosa, may also be found in tonsils
          • May also appear red
      • Exanthem phase
        • Duration
          • 7 days
          • Begins 1-2 days after enanthem
        • High fever
        • Generalized lymphadenopathy
        • Exanthem
          • Erythematous maculopapular rash
          • Blanching
          • Begins usually behind ears and spreads towards feet, usually sparing the palms and soles – cephalocaudal direction
        • Cough may persist for weeks after exanthem phase
      • Subacute sclerosing panencephalitis
        • In rare cases, patients may developed a delayed neurodegenerative disorder 10-12 years after infection
        • Results in dementia, changes in personality, seizures, coma and eventually death
    • Diagnosis
      • Clinical diagnosis with serology is always performed
      • Serology
        • Measles-specific IgM antibodies (appears at onset of exanthem phase)
    • Treatment
      • Symptomatic management
      • Supplementation with vitamin A (boosts immune response)
RougeoleDP.jpg
  • Rubella – maculopapular rash
    • Definition
      • Viral pediatric rash due to infection by the rubella virus which is now rendered uncommon to the prevalence of the MMR vaccine
    • Incubation period
      • 14-21 days
    • Presentation (milder than measles, often times infection presents with no symptoms)
      • Prodromal phase
        • Duration: 1-5 days
        • Lymphadenopathy (post-auricular, occipital)
        • Forchheimer sign: enanthem of soft palate (pinpoint petechiae)
        • Non-specific flu like symptoms:
          • Low-grade fever
          • Sore throat
          • Nausea
          • Conjunctivitis
          • Headache
      • Exanthem phase
        • Duration: 2-3 days
        • Begins usually behind the ears and spreads to trunk and extremities sparing palms and soles
        • Non-confluent/partially confluent
        • Maculopapular and pink
        • Polyarthritis may be found as well
    • Diagnosis
      • Usually a clinical diagnosis
      • Serology to confirm diagnosis (only if congenital rubella syndrome is suspected)
        • Rubella-specific IgM antibodies (can be detected only after the 4-5th day after the onset of the rash)
          • Can be detectable 6 to 8 weeks after
        • Rubella-specific IgG antibodies may also be measured as well
    • Treatment
      • Symptomatic management
Rash of rubella on back (crop).JPG

Vesicular rash

  • Chickenpox (varicella) – vesicular rash
    • Definition
      • Viral pediatric rash caused by varicella-zoster virus that is transmitted through airborne droplets affecting mostly children under the age of 15
    • Epidemiology
      • Not as common since the introduction of the varicella vaccine
    • Incubation period
      • 14-16 days
    • Presentation
      • Prodromal phase
        • 1-2 days before exanthem
        • Flu-like symptoms: fever, malaise,
      • Exanthem phase
        • Duration
          • 6 days
        • Flu-like symptoms persist
        • Rash that starts on trunk and then spreads up to face and down to extremities (middle-out spread)
        • Transition from macules to papules to vesicles that burst and then crust over
          • You may find vesicles therefore in all stages of healing
        • Very itchy
    • Diagnosis
      • Clinical diagnosis
    • Treatment
      • Avoid scratching as it can lead to scarring
      • Calamine lotion can be used to avoid scratching, oral antihistamines can be used if necessary
      • Anti-viral therapy not recommended under the age of 13, more often anti-viral therapy is recommended in immunocompromised individuals
Varicela Aranzales.jpg
  • Hand, foot, and mouth disease – vesicular rash
    • Definition
      • Viral infection caused by coxsackie group A virus that is transmitted primarily in daycare centers, schools, summer camps and hospital through the fecal-oral route and oral and nasal secretions
    • Epidemiology
      • Peak incidence is under the age of 10
    • Incubation period
      • 3-6 days
    • Presentation
      • Prodromal phase
        • Fever
        • Abdominal pain
        • Fussiness
        • Emesis
        • Diarrhea
        • Sore throat
      • Exanthem phase
        • 1-2 days after prodromal phase
        • You first will notice small oral macules develop into vesicles and ulcerate
        • Erythematous macules then develop into vesicles on hands and feet followed by
          • Groin
          • Thighs
          • Inside mouth
        • Lesions can then spread elsewhere as well
    • Diagnosis
      • Clinical diagnosis
    • Treatment
      • Symptom management
      • Adequate hydration
      • Self-limiting viral infection
Hand Foot Mouth Disease.png

Desquamating rash

  • Scarlet fever – desquamating rash
    • Definition
      • Syndrome which includes rash caused by infection by group A beta-hemolytic streptococcus (Streptococcus pyogenes) which mostly affects children between 5-15, and can be a complication of strep throat in youth
    • Epidemiology
      • Mostly children between 5-15
    • Incubation period
      • 1-7 days
    • Presentation
      • Strep throat phase
        • Tonsillopharyngitis
          • Absence of cough
          • Sore throat
          • Cervical
          • White coating on tongue
          • Tonsillar exudates
          • Cervical lymphadenopathy
          • Strawberry tongue
        • Fever, malaise
      • Exanthem phase
        • Onset: 12-48 hours after fever
        • Duration: 7 days
        • Very fine, erythematous sandy like texture, feels like sandpaper
        • Starts at neck and spreads to trunk and extremities
        • Blanches with pressure
      • Desquamating phase
        • After 7 days, rash fades and skin starts to flake off
    • Diagnosis
      • Throat culture
      • Rapid antigen strep test
    • Treatment
      • Oral penicillin V or macrolides for at least 10 days
      • Patient is no longer infectious after 24 hrs of antibiotics