Differential Diagnosis for a 4-year-old with Respiratory and Behavioral Symptoms

Single most likely diagnosis

• Acute Otitis Media (AOM): The combination of ear pain, bad breath, and a history of being "snotty" for the last week strongly suggests AOM, especially in a child of this age group. The irritability and meltdowns can be attributed to the pain and discomfort associated with the condition.

Other Likely diagnoses

• Upper Respiratory Tract Infection (URTI): Given the symptoms of being "snotty" and bad breath, a URTI is a plausible diagnosis. The ear pain could be referred pain from the throat or a sign of Eustachian tube dysfunction secondary to the URTI.
• Sinusitis: This could explain the nasal discharge, bad breath, and possibly the ear pain if the infection has spread to involve the Eustachian tubes. However, sinusitis is less common in young children compared to AOM.
• Allergic Rhinitis: If the child has allergies, this could lead to chronic nasal congestion, irritability, and possibly ear pain due to Eustachian tube dysfunction. However, the acute onset of ear pain and the specific complaint of ear pain make this less likely.

Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

• Meningitis: Although less likely, given the absence of high fever, stiff neck, or severe headache, meningitis is a critical diagnosis not to miss. Ear pain and irritability could be early signs in young children who may not be able to communicate their symptoms effectively.
• Retropharyngeal Abscess: This condition can present with neck pain, irritability, and difficulty swallowing. While less common, it's a serious condition that requires prompt diagnosis and treatment.
• Severe Dental Infection: A dental abscess could cause bad breath and ear pain if the infection is located in the upper teeth. This is less likely but could be serious if not addressed.

Rare diagnoses

• Tuberculosis (TB): Although rare in many parts of the world, TB can cause chronic respiratory symptoms, including cough and bad breath. Ear pain could be a result of TB otitis media, but this would be extremely rare and usually associated with other systemic symptoms.
• Immunodeficiency: A child with an underlying immunodeficiency might be more prone to severe or recurrent infections, including those causing the symptoms described. However, this would typically be associated with a history of recurrent infections and other signs of immunocompromised status.