Group A streptococcus pharyngitis: This is a common cause of acute pharyngitis, especially in children and adolescents, presenting with sudden onset of sore throat, fever, and swollen lymph nodes.
Hand Foot Mouth Disease (HFMD): Also a common condition, particularly in young children, characterized by sores in the mouth and a rash on the hands and feet, often accompanied by fever.

Viral pharyngitis: Caused by various viruses, it presents similarly to streptococcal pharyngitis but usually without the severe symptoms and is more likely to be accompanied by a cough.
Infectious mononucleosis: Caused by Epstein-Barr virus, it can mimic streptococcal pharyngitis with sore throat and fever but is also associated with fatigue, lymphadenopathy, and sometimes splenomegaly.
Herpangina: A viral infection that causes mouth sores and fever, similar to HFMD but typically without the hand and foot rash.

Epiglottitis: A severe, potentially life-threatening condition that can present with sore throat and fever but is distinguished by significant respiratory distress and difficulty swallowing.
Lemierre's syndrome: A rare but serious condition following a throat infection, characterized by fever, neck pain, and swelling, which can lead to sepsis and embolic events.
Peritonsillar abscess: A complication of tonsillitis that can cause severe throat pain, fever, and difficulty swallowing, requiring prompt drainage.

Diphtheria: A bacterial infection that can cause a severe sore throat and fever, distinguished by a greyish membrane covering the tonsils and throat.
Scarlet fever: Although caused by Group A streptococcus, it's less common and presents with a distinctive rash, strawberry tongue, and fever, in addition to pharyngitis symptoms.
Kawasaki disease: An illness that mainly affects children, characterized by fever, rash, swelling of hands and feet, and other symptoms, which can sometimes be confused with HFMD or viral pharyngitis in its early stages.