What is the most likely diagnosis for a previously healthy 24-year-old woman with a cough productive of white to yellow sputum and a recent upper respiratory infection?

The most likely diagnosis for the scenario presented is acute bronchitis, especially given the patient's recent history of an upper respiratory infection and the nature of her cough. Acute bronchitis often follows a viral upper respiratory infection, commonly presenting with a productive cough that brings up sputum, which can be white or yellow in color.

In young, previously healthy patients, this diagnosis is typically due to viral pathogens, and the cough may persist for several weeks even after other upper respiratory symptoms have resolved. Acute bronchitis is characterized by the inflammation of the bronchial tubes without significant findings on physical examination, such as dullness to percussion or prominent lung findings like wheezing or crackles, which can indicate other respiratory conditions.

While conditions like asthma can also cause a cough, they are typically accompanied by wheezing and shortness of breath, particularly triggered by allergens or exercise, which aren't mentioned in this scenario. Chronic bronchitis is associated with long-term irritation of the airways, often seen in smokers or individuals with long-term exposure to irritants, and would not be expected in a previously healthy 24-year-old. Community-acquired pneumonia usually presents with more significant symptoms such as fever, chills, and pleuritic chest pain, along with abnormal findings on physical examination