Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease where the immune system attacks its own healthy tissues, affecting nearly any organ system. Respiratory symptoms, including a persistent cough, are a frequent development for individuals managing SLE. Lung involvement occurs in approximately half of all people with lupus, making a cough a symptom that requires careful evaluation. This article explores how lupus activity causes a cough, examines co-existing conditions and medication side effects, and outlines the specific signs that warrant immediate medical attention.
Autoimmune Causes of Cough in Lupus Patients
Lupus can directly affect the respiratory system by triggering inflammation in various structures of the chest, leading to a cough. The most common lung-related issue is pleurisy, which involves inflammation of the pleura, the two-layered membrane surrounding the lungs and lining the chest cavity. This inflammation causes the membranes to rub against each other, typically resulting in a sharp, stabbing chest pain that worsens with deep breaths or coughing.
Pleurisy may be accompanied by a pleural effusion, where fluid accumulates between the inflamed layers of the pleura. This fluid buildup puts pressure on the lungs, which can lead to a dry or persistent cough alongside shortness of breath. Pleurisy often occurs during a lupus flare and may also present with systemic symptoms like fever and fatigue.
A more serious, though less common, direct attack on the lung tissue is acute lupus pneumonitis, affecting between 1 and 10 percent of lupus patients. This condition involves acute inflammation of the lung parenchyma. Acute pneumonitis typically presents with a dry cough, chest pain, fever, and significant shortness of breath.
In severe cases of acute pneumonitis, a patient may cough up blood (hemoptysis). This acute inflammation requires prompt treatment to prevent permanent damage to the lung tissue.
Long-term inflammation can also manifest as interstitial lung disease (ILD), which involves scarring (fibrosis) of the lung tissue. This scarring makes the lungs stiff and less elastic, impairing oxygen transfer into the bloodstream. A chronic, dry cough and trouble breathing during physical activity are characteristic symptoms of ILD.
A less frequent complication of SLE is shrinking lung syndrome, where the lung volume progressively decreases. This syndrome is caused by weakness or dysfunction of the diaphragm muscle. The reduced capacity of the lungs leads to persistent breathlessness and can trigger a cough.
Related Triggers and Medication Side Effects
Not every cough in an individual with SLE is a sign of an active lupus flare; many common triggers and treatment side effects can also be responsible. A significant factor is the use of medications to manage lupus, such as corticosteroids and other immunosuppressants. These drugs dampen the immune system but also reduce the body’s ability to fight off common pathogens.
People with lupus are more susceptible to respiratory infections, including bronchitis and pneumonia. These infections frequently cause a productive cough as the body works to clear mucus. A cough accompanied by a high or persistent fever should always be evaluated to rule out a severe infection.
Certain medications prescribed for co-existing conditions can also induce a chronic cough. Angiotensin-converting enzyme (ACE) inhibitors, often used to treat high blood pressure or protect the kidneys, are notorious for causing a persistent, dry cough. This side effect typically resolves after the medication is discontinued.
Gastroesophageal reflux disease (GERD) is another frequent co-occurrence that can trigger a chronic cough. Lupus can cause inflammation in the esophagus, potentially weakening the muscle that separates the esophagus from the stomach. This allows stomach acid to backflow, an irritation that reflexively triggers a cough, often without the sensation of heartburn.
Warning Signs Requiring Immediate Medical Attention
A cough that persists longer than two to three weeks or one that changes significantly warrants a routine medical consultation. However, certain symptoms are red flags that require immediate contact with a healthcare provider or emergency services. Sudden shortness of breath, especially if it occurs at rest, suggests a rapid decline in lung function.
Any instance of hemoptysis (coughing up blood) is a medical emergency. This can signal a severe lupus flare, such as acute pneumonitis, or a pulmonary hemorrhage (bleeding into the lung tissue). Sharp chest pain that worsens when taking a deep breath or coughing could indicate severe pleurisy or possibly a pulmonary embolism (a blood clot in the lungs).
A high fever (above 100.4 degrees Fahrenheit), combined with a cough and respiratory distress, suggests a serious infection or an acute inflammatory crisis. Individuals with lupus have a lower threshold for seeking medical advice due to their baseline immune compromise. Ignoring these acute symptoms can lead to irreversible damage or life-threatening complications.