A 13-month-old previously healthy boy was admitted to the hospital with a 7-day history of high fever and marked irritability. Over the past 3 days, his parents noted that he had developed a red rash over his face, trunk, and extremities, as well as redness and cracking of his lips. He was also noted to have swelling in his hands and feet. He was admitted because of concern of Kawasaki disease. On physical examination, he was irritable and ill-appearing, had a diffuse pleomorphic rash on his face, trunk, and extremities (Figure 177-1), nonpurulent conjunctivitis, cracked fissured lips (Figure 177-2), a tender 2 cm-diameter lymph node in his posterior cervical area, and swelling in his extremities (Figure 177-3). He was treated with intravenous immune globulin and high-dose aspirin and recovered completely. Baseline echocardiography did not reveal any coronary artery abnormalities. Follow-up echocardiograms 2 weeks and 8 weeks after his presentation were normal.

Kawasaki disease is an acute vasculitis that has emerged as the most common cause of acquired heart disease in children in the developed world. Based on the epidemiology and clinical features of this disorder, an infectious etiology is considered likely, although the precise etiology remains elusive. It is important to recognize the clinical manifestations of KD because the diagnosis is based on clinical criteria, and because timely treatment significantly reduces the risk of coronary artery disease, the most feared consequence of this disease.

Mucocutaneous Lymph Node Syndrome or Kawasaki Syndrome.

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  Eighty percent of children are under 5 years of age; rare in infants less than 3 months of age and children older than 8 years of age.¹

  
  
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  Male: Female ratio is 3:2.

  
  
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  Predominance of cases in winter-spring in temperate climates.

  
  
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  Incidence highest among Asian children, even in those living in non-Asian countries.²

  
  
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  Epidemics of disease can occur in all ethnic groups.

  
  
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  Recurrence of disease occurs rarely.

  
  
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  No person-to-person spread of disease.

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  Precise etiology is not known, but epidemiologic features (age group affected, seasonal predilection, occurrence of epidemics) point to an infectious etiology.

  
  
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  Marked immunological activation in affected patients leads to inflammatory cell infiltration of blood vessels, particularly involving the coronary arteries.

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  Occurs in previously healthy infants and children.

  
  
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  Infants and young children less than 5 years of age are most commonly affected.

  
  
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  Annual incidence in Japanese children is 215 per 100,000 children younger than 5 year of age.²

  
  
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  The attack rate in Caucasian children is 10-fold lower than in Asians; African- Americans have an intermediate incidence.

  
  
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  Risk factors for the development of coronary artery disease on those affected include:

  
  
  
  
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    Age younger than 1 year.

    
    
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    Duration of fever longer than 16 days.

    
    
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    Recurrence of fever after an afebrile period of at least 48 hours.

    
    
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    Anemia.

    
    
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    Thrombocytopenia.

    
    
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    Hypoalbuminemia.

Clinical Features

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  Three phases of KD are classically described:

  
  
  
  
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    The acute phase, which lasts 7 to 14 days and is characterized by the classic clinical diagnostic criteria (see the following section).

    
    
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    The subacute phase occurs from about day 10 to day 25 of the illness, characterized by periungual desquamation, arthritis, and thrombocytosis.

    
    
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    The convalescent phase occurs from when all the clinical signs of illness have resolved until 6 to 8 weeks after the onset of the illness.

  
  
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  The diagnosis of classic acute KD relies on clinical criteria, which include the presence of fever persisting for at least 5 days, along with four or the following five clinical findings:

  
  
  
  
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    Bilateral bulbar conjunctival injection without exudate (Figure 177-4).

    
    
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    Erythematous mouth and pharynx, red, cracked, fissured lips, and “strawberry tongue” (Figure 177-5).

    
    
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    Polymorphous, generalized, erythematous rash (may be maculopapular, morbilliform, scarlatiniform, or erythema multiforme-like; Figure 177-6).

    
    
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    Erythema and swelling of the hands and feet, with subsequent periungual desquamation (Figures 177-7 to 177-9)

    
    
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    Cervical lymph node enlargement (usually unilateral) with at least one lymph node measuring 1.5 cm in diameter (Figure 177-10).

  
  
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  Other findings that may be present include:

  
  
  
  
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    Irritability, which is often marked.

    
    
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    Abdominal pain.

    
    
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    Diarrhea and vomiting.

    
    
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    Arthritis or arthralgia.

    
    
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    Meningismus.

  
  
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  Coronary artery aneurysms, myocarditis, and pericarditis are well-known complications.

  
  
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  Incomplete cases of KD can occur, particularly in young infants, usually heralded by the presence of fever and fewer than 4 of the 5 clinical features of the illness; these can be challenging to diagnose.^3,4

  
  
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  Periungual desquamation occurs during the subacute phase of the illness, usually occurring from day 10 to day 25 of the illness (Figure 177-9).