A 6-year-old female has a 10-day history of thick nasal discharge and nasal congestion. What is the most likely diagnosis?

The clinical presentation of thick nasal discharge and nasal congestion in a 6-year-old female for a duration of 10 days suggests an infection that has progressed beyond the typical course of a viral illness. Acute bacterial rhinosinusitis is characterized by symptoms lasting longer than 10 days, particularly if they are worsening or not improving after an initial phase that resembles a viral upper respiratory infection.

In the case of acute bacterial rhinosinusitis, the presence of thick purulent nasal discharge, especially with facial pain or pressure, headache, or worsening symptoms after an initial improvement, supports the diagnosis. The thick discharge is a key indicator that the sinus cavities may be involved and that a bacterial infection is likely.

In contrast, a viral upper respiratory infection usually presents with milder symptoms that generally improve within 7 to 10 days. Allergic rhinitis typically features clear nasal discharge, sneezing, and itchy eyes, while foreign body obstruction would present with unilateral symptoms and possibly a sudden onset of nasal discharge. Thus, the combination of the duration of symptoms, the nature of the discharge, and the age of the patient align with the diagnosis of acute bacterial rhinosinusitis.