Kawasaki's disease is a disease of unknown cause. The characteristic clinical 
features of Kawasaki's disease are fever> or =102 degrees F for> or =5 days 
accompanied by a bilateral bulbar conjunctivitis/conjunctival suffusion, 
erythematous rash, cervical adenopathy, pharyngeal erythema, and swelling of the 
dorsum of the hands/feet. Kawasaki's disease primarily affects children and is 
rare in adults. In children, Kawasaki's disease is more likely to be associated 
with aseptic meningitis, coronary artery aneurysms, and thrombocytosis. In adult 
Kawasaki's disease, unilateral cervical adenopathy, arthritis, conjunctival 
suffusion/conjunctivitis, and elevated serum transaminases (serum glutamic 
oxaloacetic transaminase [SGOT]/serum glutamate pyruvate transaminase [SGPT]) 
are more likely. Kawasaki's disease in adults may be mimicked by other acute 
infections with fever and rash, that is, group A streptococcal scarlet fever, 
toxic shock syndrome (TSS), and Rocky Mountain Spotted Fever (RMSF). Because 
there are no specific tests for Kawasaki's disease, diagnosis is based on 
clinical criteria and the syndromic approach. In addition to rash and fever, 
scarlet fever is characterized by circumoral pallor, oropharyngeal edema, 
Pastia's lines, and peripheral eosinophilia, but not conjunctival suffusion, 
splenomegaly, swelling of the dorsum of the hands/feet, thrombocytosis, or an 
elevated SGOT/SGPT. In TSS, in addition to rash and fever, there is conjunctival 
suffusion, oropharyngeal erythema, and edema of the dorsum of the hands/feet, an 
elevated SGOT/SGPT, and thrombocytopenia. Patients with TSS do not have cervical 
adenopathy or splenomegaly. RMSF presents with fever and a maculopapular rash 
that becomes petechial, first appearing on the wrists/ankles after 3 to 5 days. 
RMSF is accompanied by a prominent headache, periorbital edema, conjunctival 
suffusion, splenomegaly, thrombocytopenia, an elevated SGOT/SGPT, swelling of 
the dorsum of the hands/feet, but not oropharyngeal erythema. We present a case 
of adult Kawasaki's disease with myocarditis and splenomegaly. The patient's 
myocarditis rapidly resolved, and he did not develop coronary artery aneurysms. 
In addition to splenomegaly, this case of adult Kawasaki's disease is remarkable 
because the patient had highly elevated serum ferritin levels of 944-1303 ng/mL; 
(normal<189 ng/mL). To the best of our knowledge, this is the first report of 
adult Kawasaki's disease with highly elevated serum ferritin levels. This is 
also the first report of splenomegaly in adult Kawasaki's disease. We conclude 
that Kawasaki's disease should be considered in the differential diagnosis in 
adult patients with rash/fever for> or =5 days with conjunctival suffusion, 
cervical adenopathy, swelling of the dorsum of the hands/feet, thrombocytosis 
and otherwise unexplained highly elevated ferritin levels.