Chronic Obstructive Pulmonary Disease (COPD): This is a common cause of dyspnea, especially in smokers or those with a history of smoking. The absence of cough, fever, or chest pain does not rule out COPD, as these symptoms can be intermittent or mild.

Heart Failure: Dyspnea is a hallmark symptom of heart failure, which can occur without cough, fever, or chest pain, especially in the early stages or in patients with diastolic dysfunction.
Asthma: Although asthma often presents with wheezing and cough, some patients may experience dyspnea as the primary symptom, particularly if they have a variant form like cough-variant asthma or if their symptoms are well-controlled with medication.
Anxiety or Panic Disorder: These conditions can cause significant dyspnea without any underlying pulmonary or cardiac pathology, often accompanied by other symptoms like palpitations or fear of dying.

Pulmonary Embolism (PE): Although PE often presents with chest pain and cough, it can occasionally manifest with isolated dyspnea. Missing this diagnosis can be fatal, so it's crucial to consider it, especially in patients with risk factors like recent travel, surgery, or family history of clotting disorders.
Cardiac Tamponade: This is a life-threatening condition where fluid accumulates in the sac around the heart, impeding its ability to pump. Dyspnea can be a presenting symptom, and it requires immediate medical attention.
Pneumothorax: A spontaneous pneumothorax can cause sudden dyspnea, and while chest pain is common, it's not universal. This condition can quickly become life-threatening if not addressed promptly.

Lymphangitic Carcinomatosis: This rare condition involves the spread of cancer to the lymphatic vessels in the lungs, leading to dyspnea. It's more common in patients with known cancer but can be a presenting symptom in some cases.
Neuromuscular Disorders (e.g., Myasthenia Gravis, Amyotrophic Lateral Sclerosis): These conditions can affect the muscles used for breathing, leading to dyspnea. They are less common but important to consider in the differential diagnosis, especially if other neurological symptoms are present.
High-Altitude Pulmonary Edema: For individuals who have recently traveled to high altitudes, this condition can cause dyspnea without the typical symptoms of cough, fever, or chest pain. It's a rare but potentially life-threatening condition that requires immediate descent to lower altitudes.