A 3-year-old who has persistent drainage from one nostril after treatment for a URI may likely have what condition?

In a 3-year-old child with persistent drainage from one nostril after treatment for an upper respiratory infection (URI), the most likely condition is the presence of a foreign body. When a child experiences unilateral nasal drainage that continues beyond the typical duration of a URI, it raises suspicion for a foreign object lodged in the nasal passage, which can cause localized inflammation and discharge.

The symptoms often include foul-smelling nasal drainage, particularly when a foreign body is involved, and the drainage may not respond to conventional URI treatments. This condition requires careful examination and potentially medical intervention to remove the foreign object and address any complications that may arise from it.

The other options do not align as closely with the symptoms described. Unresolved URI could lead to ongoing symptoms, but typically this would present bilaterally rather than unilaterally. Dental caries might result in sinus issues leading to drainage, but it wouldn’t be limited to just one nostril and is less commonly associated in such a young child without additional dental symptoms. Allergic rhinitis usually presents with bilateral symptoms more consistently and is often associated with other allergic manifestations such as sneezing and itching, which are not specified in this case.