Malaise is an often-misused term. The non-specific symptom presents with a variety of diseases and illnesses and is hard to define: essentially, it is a feeling of weakness, discomfort, or pain — the sense that something is just not right. The severity of malaise depends on the cause. It ranges from mild to serious, and some experts believe it is caused by activation of the immune response.
Malaise vs. Fatigue
Malaise is often confused with fatigue. Though the two can occur simultaneously, they are distinct symptoms. Malaise is a general feeling of discomfort that is non-specific and can be hard to explain. It can occur with just about any health condition. Fatigue is the physical feeling of not having any energy. Further, fatigue differs from tiredness or exhaustion in that rest may not alleviate it.
Infectious Diseases
Because malaise appears to be brought on by an immune response, it is often experienced during an infection. Some infections that cause malaise are short-term, like the flu, pneumonia, bronchitis, and viral colds. When the infection resolves, so do the symptoms. Other infections are long-term, such as HIV, hepatitis, and tuberculosis. These can cause ongoing malaise with or without flare-ups.
Malaise and the Immune Response
The body has a complex reaction to infection. White blood cells produce antibodies that attack foreign bodies, like bacteria and viruses, and cytokines to direct the immune response. Malaise and other symptoms of infection, such as fever, rash, and headaches, are the result of the immune system responding to an infection.
Heart and Lung Disease
Heart and lung diseases, like congestive heart failure or COPD, can also cause malaise, especially as they progress. The circulatory and respiratory systems work together to deliver oxygen to the tissues. When the tissues are not getting enough, the heart and lungs must work harder. Anything that interferes with oxygenation can cause malaise.
Endocrine and Metabolic Diseases
Metabolic and endocrine diseases, including diabetes, adrenal gland dysfunction, and thyroid disease, also cause malaise. These diseases result in the production of too many or too few key hormones. Many body processes can be affected depending on the hormone, including inflammatory responses, salt and water balances, and blood sugar. These abnormalities can cause malaise.
Cancer
Malaise can also be a symptom of cancers, including lymphoma, leukemia, and solid tumors. Studies show that among patients with advanced cancer, malaise was the most common symptom contributing to patient suffering. The pain was also an important factor, but medication usually alleviates this. An ongoing sense of malaise is more difficult to treat.
Anemia
Anemia has multiple causes, but each one results in a decrease in the number of healthy red blood cells circulating through the body. People with anemia often feel tired and cold. Untreated anemia can lead to irregular heartbeat, heart failure, and a greater risk of infection, any of which can result in an ongoing feeling of malaise.
Depression
Malaise is a common symptom of depression. The exact cause of depression is unknown, but doctors believe that chemical changes in the brain and genetics are contributing factors. People with depression often see everything negatively and feel tired and hopeless, lose their appetite, and sleep too much or not enough. Ongoing malaise is a sign of persistent depressive disorder or dysthymia, which occurs when someone experiences a depressed mood for at least two years.
Medications
Medications are associated with a number of side effects. Some may cause malaise when taken alone or in conjunction with others. Some prescription drugs that are prone to causing malaise include antihistamines, anti-seizure medications, psychiatric medications, beta-blockers, and other heart medications. If stopping the medication is not an option, the physician may prescribe an alternative or adjust the dose to try to alleviate the effects.
Chronic Fatigue Syndrome and Post-Exertional Malaise
Chronic fatigue syndrome (CFS) is a complicated disorder that experts do not fully understand. People with CFS experience extreme fatigue that does not resolve with rest and does not have an underlying medical cause. One of the symptoms of CFS is post-exertional malaise; symptoms worsen and persist for anywhere from 12 to 48 hours after even minor physical exertion.