This diagnostic criterion requires the exclusion of infectious diseases, malignancies, and other rheumatic diseases. A diagnosis can be made if 5 criteria are met (including at least 2 major criteria).

The Yamaguchi diagnostic criteria are currently the most sensitive among the proposed diagnostic criteria.

Typical rash: During fever, pale red, non-itchy maculopapular or macular rash can be seen on the trunk and limbs.