Pneumococcal pneumonia with pneumothorax: This is a common cause of pneumonia in adults, and pneumothorax can be a complication, especially in smokers. The fever and pneumothorax presentation aligns with this diagnosis.

Tuberculosis (TB) with pneumothorax: Although the PPD (purified protein derivative) test is negative, it does not entirely rule out TB, especially in smokers who may have a higher risk of TB. TB can cause pneumothorax, and the fever is consistent with this diagnosis.
Pulmonary abscess with pneumothorax: A pulmonary abscess can cause fever and, if it ruptures into the pleural space, can lead to pneumothorax. Smoking is a risk factor for developing a pulmonary abscess.
Lung cancer with pneumothorax: Lung cancer is a concern in smokers, and while less common, it can cause pneumothorax either by direct invasion into the pleura or by causing a bronchopleural fistula.

Pulmonary embolism with pneumothorax: Although less common, a pulmonary embolism can cause pneumothorax, especially if there is infarction of lung tissue leading to rupture into the pleural space. This diagnosis is critical to consider due to its high mortality rate if untreated.
Catamenial pneumothorax: In female patients, this rare condition associated with menstruation can cause recurrent pneumothoraces. It's essential to consider in female smokers presenting with pneumothorax, even though the patient's gender is not specified.

Lymphangioleiomyomatosis (LAM): A rare lung disease that primarily affects women, characterized by the abnormal growth of smooth muscle-like cells in the lungs, which can lead to pneumothorax. It's less likely but should be considered in the differential diagnosis of recurrent or spontaneous pneumothorax.
Pulmonary Langerhans cell histiocytosis: A rare disease that can cause cystic lung lesions and pneumothorax, more commonly seen in smokers. It's an important consideration in smokers with unexplained lung cysts and pneumothorax.