Redness of the lips and mouth is the initial manifestation of oropharyngeal changes caused by cutaneous mucosal lymph node syndrome. Kawasakisyndrome is an acute systemic vasculitis that affects mainly infants and children. Despite extensive research, the etiology of Kawasaki disease is still unclear, but numerous epidemiological and clinical observations suggest that Kawasaki disease is caused by infection, given the fever, rash, conjunctival congestion, cervical lymph node enlargement, the prevalence in children, and the apparent geographic distribution of outbreaks in this self-limiting disease suggest an infection-related pathogenesis. Kawasaki disease associated with red lips should be differentiated from the following diseases: 1. scarlet fever: 1) rash starts on the third day after onset; 2) rash pattern is similar to measles and erythema multiforme; 3) age of onset is infancy and younger children; 4) penicillin is not effective. 2, juvenile rheumatoid disease: ① fever period is shorter, the rash is more transient; ② hands and feet are hard and swollen, showing often plantar flushing; ③ rheumatoid factor negative. 3, exudative polymorphic erythema: ① eyes, lips, no purulent discharge and pseudomembrane formation; ② rash does not include blisters and crusts. 4. Typical periarteritis nodosa: ① the latter vasculitis shows obvious fibrinoidenecrosis, while such necrotic changes are rare or only slight in MCLS; ② typical periarteritis nodosa rarely involves the pulmonary arteries. 5. Systemic lupus erythematosus: (1) the rash is not significant on the face; (2) the total white blood cell count and platelets are generally elevated; (3) antinuclear antibodies are negative; (4) the age of prevalence is more common in infants and boys. 6. Infantile nodular polyarteritis and rash viral infection: ① flushed lips, dry cracking, bleeding, and prune tongue; ② hard swelling of hands and feet, often plantar flushing and membrane peeling at the end of fingers and toes; ③ conjunctiva without edema or discharge; ④ total leukocyte count and granulocyte percentage are increased, with left shift of nucleus; ⑥ blood sedimentation and C-reactive protein are significantly increased. 7. Acute lymphadenitis: ① enlargement of cervical lymph nodes and mild pressure pain, no local skin and subcutaneous tissue redness and swelling; ② no purulent lesions. 8, viral myocarditis: ① prominent coronary artery lesions; ② characteristic hand and foot changes; ③ persistent high fever. 9, rheumatic myocarditis: ① prominent coronary artery lesions; ② no meaningful heart murmur; ③ the age of onset is mainly infants and children.