The acute phase lasts 7 to 15 days and is the period when most diagnostic clinical features occur. Fever defines this phase: it lasts 7 to 15 days (mean 12 days), typically is high and unremitting even with antipyretics, and is associated with irritability.
All physical findings are a consequence of the vasculitis. Bulbar conjunctivitis is bilateral, nonexudative, and spares the limbus. It may persist for several weeks. Mucocutaneous changes may include bright red erythema of the lips with cracking, a strawberry tongue, and hyperemia of the oral mucous membranes. The pharynx may be erythematous, but exudate is not present and vesicles are not expected.
Cervical adenopathy is an early feature and the least consistently present finding. Nodes may not be prominent but they should be at least 1.5 cm in diameter to be considered part of disease. Involvement of the anterior cervical chain is most common and may be unilateral. The lymphadenopathy is nonsuppurative and may disappear rapidly.
Skin changes usually accompany the fever throughout the acute phase and then gradually fade. These rashes are red; polymorphous; and may be morbilliform, maculopapular, scarlatiniform, or pustular; however, vesiculation does not occur.4,5 The rash may actually vary in character from place to place in a single child and develops in most children. It is mostly seen on the trunk and may be prominent in the diaper area.
Changes in the peripheral extremities occur within a few days after onset. Any part of the hands and feet may be edematous. The palms and soles may be erythematous.
There are many other ancillary features and alternate presentations of KD. Involvement of almost any system can occur (see “Other Complications”). Although not considered diagnostic criteria, arthralgia and arthritis, urethritis, gastrointestinal complaints, uveitis, and meningitis are the most common findings and helpful in supporting the diagnosis.
The subacute phase lasts for approximately 2 to 4 weeks and begins with resolution of fever and elevation of platelet count. It ends with the return of platelet counts to near normal levels.
This phase is dominated by desquamation that may begin before the resolution of fever. Desquamation is a common feature of KD. It is noted first in the periungual region, with peeling underneath the fingernails and toenails. It may also be prominent in the diaper area.
Thrombocytosis is another constant feature of the subacute phase, with platelet counts in the range of 500,000 to 3,000,000/mm3. Thrombocytosis is rare in the first week of the illness, appears in the second week, peaks in the third week, and returns gradually to normal about a month after onset in uncomplicated illness.
It is during the subacute phase that complications such as coronary artery aneurysms and hydrops of the gall bladder develop (although coronary artery aneurysms may develop during the acute phase as well).
Recovery or Convalescent Phase
The recovery phase may last months to years. Some coronary artery disease is first recognized during this phase. Resolution of coronary artery disease may occur during this phase.