Viral Pharyngitis: This is the most common cause of sore throat in children, often accompanied by fever and can sometimes include stomach ache due to the viral infection affecting the gastrointestinal system.

Streptococcal Pharyngitis: A bacterial infection that causes sore throat, fever, and can be associated with stomach pain. It's a common condition in children and requires antibiotic treatment.
Influenza: Can present with sore throat, fever, and body aches, including stomach ache, especially in children.
Mononucleosis (Mono): Caused by the Epstein-Barr virus, it can lead to sore throat, fever, and abdominal pain due to spleen enlargement.

Epiglottitis: A severe and potentially life-threatening condition that can cause sore throat, fever, and abdominal pain. It requires immediate medical attention.
Appendicitis: Although the primary symptom is abdominal pain, it can sometimes be accompanied by fever and sore throat, especially if the appendix is near the abdominal wall or has ruptured.
Kawasaki Disease: An acute febrile illness that can cause sore throat, fever, and abdominal discomfort, along with other symptoms like rash and swollen lymph nodes. It's critical to diagnose early to prevent cardiac complications.

Lemierre's Syndrome: A rare condition following a bacterial pharyngitis infection, leading to fever, sore throat, and potentially abdominal pain due to septic thrombophlebitis of the internal jugular vein.
Peritonsillar Abscess: A complication of tonsillitis that can cause severe sore throat, fever, and sometimes abdominal pain due to the infection's proximity to the digestive tract.
Rheumatic Fever: A rare complication of untreated streptococcal pharyngitis, which can lead to fever, abdominal pain, and sore throat among other symptoms.