A young patient presents with facial pain and yellow nasal discharge. What is the appropriate initial treatment?

The appropriate initial treatment for a young patient presenting with facial pain and yellow nasal discharge is amoxicillin. This presentation is commonly associated with bacterial sinusitis, particularly if symptoms have persisted for more than 10 days or have worsened after an initial viral upper respiratory infection.

Amoxicillin is a first-line antibiotic recommended for acute bacterial sinusitis due to its effectiveness against common pathogens, such as Streptococcus pneumoniae and Haemophilus influenzae. It addresses the infection while the patient experiences symptoms such as facial pain and purulent nasal discharge.

In contrast, diphenhydramine is an antihistamine primarily used for allergic reactions and does not address bacterial infections. Doxycycline is often reserved for specific conditions and is not typically a first-line choice for sinusitis, especially in young patients. Erythromycin has limited use due to resistance and is not a preferred treatment for bacterial sinusitis.