Diagnostic Approach to Abdominal Rash in Children

Immediate Diagnostic Considerations

The American Heart Association recommends considering Kawasaki disease as a critical diagnosis in any 1-year-old with fever and rash starting from the abdomen, especially if accompanied by other features such as conjunctivitis, oral changes, or extremity findings, as this age group is at highest risk for coronary complications 1
Kawasaki disease should be considered in every child with fever of at least several days' duration, rash, and nonpurulent conjunctivitis, especially in children ≤1 year old, in whom the diagnosis is frequently missed 1
The American Academy of Pediatrics suggests that young infants may present with fever and few principal clinical features; incomplete Kawasaki disease should be suspected in infants aged ≤6 months with fever ≥7 days' duration and laboratory evidence of systemic inflammation 1
Echocardiography should be performed in any infant aged ≤6 months with unexplained fever ≥7 days and no other explanation for the febrile illness, as recommended by the American Heart Association 1

The American College of Radiology recommends that abdominal distension, tenderness, vomiting, or hypoactive bowel sounds suggest potential intra-abdominal injury requiring imaging 2
Abdominal wall bruising in a 1-year-old should raise concern for non-accidental trauma; up to 10% of abused children have intra-abdominal injury, according to the American College of Radiology 2
If suspected intra-abdominal injury, the American College of Radiology suggests obtaining contrast-enhanced CT of abdomen/pelvis and considering skeletal survey for children ≤24 months 2
Bacterial infection is suggested by crusting or weeping of the rash, as indicated by the British Medical Journal 3
Grouped, punched-out erosions or vesiculation indicate possible herpes simplex infection, according to the British Medical Journal 3

The American Heart Association recommends treating Kawasaki disease with IVIG within 10 days of fever onset if ≥4 principal features are present (including rash) 1
If 2-3 principal features are present, the American Heart Association suggests considering incomplete Kawasaki disease and obtaining echocardiography plus laboratory markers (CBC, CRP, ESR, albumin, liver enzymes) 1
The American College of Radiology recommends examining for abdominal tenderness, distension, bruising, or abnormal bowel sounds to rule out serious abdominal pathology 2
The American Academy of Pediatrics suggests that pain control facilitates better examination without affecting diagnostic accuracy, and recommends not withholding pain medication while awaiting diagnosis 4