Most common differential diagnosis for appendicitis in children is
Differential diagnosis of acute appendicitis in children Gastroenteritis Mesenteric adenitis Meckel's diveiculitis Intussusception Henoch-Schonlein purpura Lobar pneumonia Ref: Bailey & Love&;s Sho Practice of Surgery,E25,Page-1209
Gastroenteritis
Mesentric lymphadenopathy
Intussusception
Meckel's diveiculitis
G.I.T