Atypical Kawasaki disease is more common in which age groups?

• A. Infants under 6 months
• B. Children over 9 years
• C. Both infants under 6 months and children over 9 years
• D. Children 2-5 years

Answer: (C)

Atypical Kawasaki disease occurs when the fever is present but the full set of diagnostic signs isn’t, and age influences how the illness presents. Kawasaki disease most often affects young children, especially around ages 1–2, with a fairly recognizable cluster of features. In the youngest infants (under six months) and in older children (typically over nine years), the illness often lacks the classic picture, so it presents in an atypical or incomplete way. In these groups, fever may be the prominent feature while other criteria such as conjunctival injection, mucous membrane changes, rash, extremity changes, or cervical lymphadenopathy are less conspicuous or absent. Because the presentation can be subtle, recognition may be delayed, increasing the risk of coronary artery involvement if not treated promptly with IVIG and appropriate management. Therefore, atypical KD is more common in both infants under six months and in children over nine years, compared with the 2–5-year-old group where the classic presentation is more typical.