The differential diagnosis of adenoiditis can be challenging as many upper respiratory tract infections show similar patterns. Here are some conditions that need to be differentiated from adenoiditis:

1. Tonsillitis
2. Viral upper respiratory tract infection
3. Sinusitis
4. Pharyngitis

Other conditions that may present with similar symptoms include:

1. Peritonsillar abscess: Presents with severe sore throat, otalgia, fever, a “hot potato” or muffled voice, drooling, and trismus.
2. Croup: Characterized by cough, stridor but no drooling, hoarseness, difficulty breathing, common cold, runny nose, and fever.
3. Epiglottitis: Presents with stridor and drooling but no cough, difficulty breathing, fever, chills, difficulty swallowing, and hoarseness of voice.
4. Foreign body
5. Deviated nasal septum
6. Nasal polyps (associated with cystic fibrosis in children)
7. Allergic rhinitis
8. Choanal atresia
9. Pyriform aperture stenosis
10. Nasopharyngeal neoplasm

Diagnosis is typically enhanced by flexible fiberoptic nasopharyngoscopy. Please consult with a healthcare professional for an accurate diagnosis..