Acute Bronchitis: This is often the most common diagnosis for patients presenting with fever and cough, typically caused by a viral infection. The symptoms usually include a productive cough, fever, and sometimes malaise.

Pneumonia: Both viral and bacterial pneumonia can present with fever and cough. The presence of additional symptoms such as shortness of breath, chest pain, or sputum production can help differentiate pneumonia from other diagnoses.
Influenza: Especially during flu season, influenza can cause fever, cough, and other systemic symptoms like body aches and fatigue.
Acute Sinusitis: If the cough is postnasal drip in nature, acute sinusitis could be a likely diagnosis, especially if accompanied by facial pain, headache, or nasal congestion.

Tuberculosis (TB): Although less common in many areas, TB is a critical diagnosis not to miss due to its public health implications and the need for specific treatment. A chronic cough, weight loss, and night sweats might accompany the fever.
Pulmonary Embolism: While cough and fever are not the most typical presentations, pulmonary embolism can occasionally manifest this way, especially if there's an associated infection or if the embolism causes pulmonary infarction.
Lung Abscess: This condition can present with fever, cough, and sometimes sputum production, often with a more severe clinical picture than pneumonia.

Sarcoidosis: This autoimmune disease can cause cough and fever among other systemic symptoms, but it's less common and usually presents with additional findings like lymphadenopathy or skin lesions.
Histoplasmosis or Coccidioidomycosis: These fungal infections can cause fever and cough, especially in endemic areas or in individuals with exposure history (e.g., to bird droppings or soil).
Lymphoma: Although rare, lymphoma can initially present with systemic symptoms like fever and cough, especially if there's mediastinal involvement.