Cough is one of the most common reasons people consult their physicians. To narrow the list of diagnostic possibilities for a given person’s cough, doctors classify coughs that have been present for less than 3 weeks as “acute,” those lasting 3 to 8 weeks as “prolonged acute” and those lasting more than 8 weeks as “chronic.” These categories are somewhat arbitrary, however. A chronic cough must begin sometime, and if you see your doctor within the first few days of symptom onset, your cough will be labeled “acute.” A cough that is not associated with a fever, whether acute or chronic, could have many causes.
Not all respiratory infections cause a fever. Many viruses, such as the rhinoviruses that cause colds, do not trigger high fevers. Likewise, pertussis, or whooping cough, might not prompt a fever throughout its entire course, particularly in an adolescent or adult who has been previously vaccinated. And sinusitis, which often develops following a common cold, may not cause a fever. Respiratory infections often cause other symptoms, such as body aches, nausea, sore throat or runny nose, which may help distinguish them from other causes of acute cough. Your physician may need to do some investigating to determine if an infection is the cause of your cough.
Asthma is a respiratory disease that manifests with inflammation, reversible airway narrowing and reduced airflow. Cough-variant asthma, which causes a cough but not the wheezing and breathing difficulties typically associated with asthma, is the most common cause of chronic cough. Even if you have never been diagnosed with asthma before, an otherwise unexplained cough could herald the onset of asthma. According to a 2011 review in “Therapeutic Advances in Chronic Disease,” several other asthma-like conditions, such as allergic cough or eosinophilic bronchitis -- a condition characterized by elevated numbers of immune cells in your airways -- can trigger coughs, and these conditions often do not cause fever.
Gastroesophageal reflux disease, or acid reflux disease, is a common cause of chronic cough in adults. If you have frequent heartburn, a new cough without fever could be a symptom of worsening acid reflux. However, it is possible to have acid reflux without heartburn. A cough is sometimes the only symptom of GERD. If you do have GERD, treatment with acid-blocking medications may alleviate your cough, but not all GERD-related coughs resolve with treatment. A physician's guidance is essential in such situations.
Certain medications have a reputation for causing a cough. Angiotensin-converting enzyme, or ACE, inhibitors, such as captopril (Capoten), lisinopril (Prinivil, Zestril) and enalapril (Vasotec), trigger a cough in up to 20 percent of people who take them. The “ACE-inhibitor cough” is typically a dry, tickling cough that is most troublesome in the evenings and is not associated with fever. It can begin within a few days of starting the medication, or it may not start until you have taken the drug for several months. If your doctor thinks your medication is causing a cough, switching to another drug may address the problem.
Exposure to airborne irritants, such as dusts, fumes, molds or secondhand smoke, is a common cause of cough without fever. Such exposures can occur in your home, workplace or outdoor environment. Since many inhaled irritants are not visible to the naked eye and do not have distinct odors, irritant-induced coughs can be difficult to diagnose. People who have smoked for many years may develop chronic bronchitis, or “smoker’s cough.” Certain autoimmune diseases, such as sarcoidosis, can involve your lungs and trigger a cough. Rarely, a cough is the initial symptom of lung cancer. None of these conditions is necessarily associated with a fever. If your cough persists or worsens, your doctor may need to perform a variety of tests to identify its cause. A chest x-ray, allergy testing, pulmonary function tests to evaluate lung function, pH testing to rule out acid reflux and sputum examination to detect abnormal cells in your airways might all be included in your evaluation.