Lupus is an autoimmune disease where the body's immune system becomes hyperactive and attacks normal, healthy tissue. This results in symptoms such as inflammation, swelling, and damage to joints, skin, kidneys, blood, the heart, and lungs.
Under normal function, the immune system makes proteins called antibodies in order to protect and fight against antigens such as viruses and bacteria. Lupus makes the immune system unable to differentiate between antigens and healthy tissue. This leads the immune system to direct antibodies against the healthy tissue – not just antigens – causing swelling, pain, and tissue damage.
(* An antigen is a substance capable of inducing a specific immune response.)
What are the different types of lupus?
Several different kinds of lupus have been identified, but the type that we refer to simply as lupus is known as systemic lupus erythematosus or SLE. Other types include discoid (cutaneous), drug-induced, and neonatal.
Patients with discoid lupus have a version of the disease that is limited to the skin. It is characterized by a rash that appears on the face, neck, and scalp, and it does not affect internal organs. Less than 10% of patients with discoid lupus progress into the systemic form of the disease, but there is no way to predict or prevent the path of the disease.
SLE is more severe than discoid lupus because it can affect any of the body's organs or organ systems. Some people may present inflammation or other problems with only skin and joints, while other SLE sufferers will see joints, lungs, kidneys, blood, and/or the heart affected. This type of lupus is also often characterized by periods of flare (when the disease is active) and periods of remission (when the disease is dormant).
Drug-induced lupus is caused by a reaction with certain prescription drugs and causes symptoms very similar to SLE. The drugs most commonly associated with this form of lupus are a hypertension medication called hydralazine and a heart arrhythmia medication called procainamide, but there are some 400 other drugs that can also cause the condition. Drug-induced lupus is known to subside after the patient stops taking the triggering medication.
A rare condition, neonatal lupus occurs when a mother passes autoantibodies to a fetus. The unborn and newborn child can have skin rashes and other complications with the heart and blood. Usually a rash appears but eventually fades within the first six months of the child's life.
Who is affected by lupus?
According to the Lupus Foundation of America (LFA), 1.5 to 2 million Americans have some form of lupus. The prevalence is about 40 cases per 100,000 persons among Northern Europeans and 200 per 100,000 persons among blacks. Although the disease affects both males and females, women are diagnosed 9 times more often than men, usually between the ages of 15 and 45. African-American women suffer from more severe symptoms and a higher mortality rate.
Other risk factors include exposure to sunlight, certain prescription medications, infection with Epstein-Barr virus, and exposure to certain chemicals.
What causes lupus?
Although doctors are do not know exactly what causes lupus and other autoimmune diseases, most believe that lupus results from both genetic and environmental stimuli.
Since lupus is known to occur within families, doctors believe that it is possible to inherit a genetic predisposition to lupus. There are no known genes, however, that directly cause the illness. It is probable that having an inherited predisposition for lupus makes the disease more likely only after coming into contact with some environmental trigger.
The higher number of lupus cases in females than in males may indicate that the disease can be triggered by certain hormones. Physicians believe that hormones such as estrogen regulate the progression of the disease because symptoms tend to flare before menstrual periods and/or during pregnancy.
Certain environmental factors have been known to cause lupus symptoms. These include:
- Extreme stress
- Exposure to ultraviolet light, usually from sunlight
- Some medications and antibiotics, especially those in the sulfa and penicillin groups
- Some infections, such as cytomegalovirus (CMV), parvovirus (such as fifth disease), hepatitis C infections, and the Epstein-Barr virus (in children)
- Chemical exposure to compounds such as trichloroethylene in well water and dust
What are the symptoms of lupus?
Since no two cases of lupus are exactly alike, there is a wide range of symptoms that are known to affect many parts of the body. Sometimes symptoms develop slowly or appear suddenly; they can be mild, severe, temporary, or permanent. Most people with lupus experience symptoms in only a few organs, but more serious cases can lead to problems with kidneys, the heart, the lungs, blood, or the nervous system.
Lupus episodes, or flares, are usually noted by a worsening of some of the following symptoms:
- Achy joints (arthralgia), arthritis, and swollen joints, especially in wrists, small joints of the hands, elbows, knees, and ankles
- Swelling of the hands and feet due to kidney problems
- Fever of more than 100 degrees F (38 degrees C)
- Prolonged or extreme fatigue
- Skin lesions or rashes, especially on the arms, hands, face, neck, or back
- Butterfly-shaped rash (malar rash) across the cheeks and nose
- Anemia (oxygen carrying deficiency of red blood cells)
- Pain in the chest on deep breathing or shortness of breath
- Sun or light sensitivity (photosensitivity)
- Hair loss or alopecia
- Abnormal blood clotting problems
- Raynaud's phenomenon: fingers turn white and/or blue or red in the cold
- Mouth or nose ulcers
- Weight loss or gain
- Dry eyes
- Easy bruising
- Anxiety, depression, headaches, and memory loss
Lupus can also lead to complications in several areas of the body. These include:
- Kidneys – serious kidney damage is a primary cause of death for lupus sufferers.
- Central nervous system – lupus can cause headaches, dizziness, memory problems, seizures, and behavioral changes.
- Blood and vessels – lupus causes an increased risk of anemia, bleeding, blood clotting, and vessel inflammation
- Lungs – noninfectious pneumonia and difficulty breathing due to inflammation of the chest cavity are more likely with lupus
- Heart – heart muscle and artery inflammation are more likely with the disease, and lupus increases the chances of cardiovascular disease and heart attacks.
- Infection – lupus treatments tend to depress the immune system making your body more vulnerable to infection.
- Cancer – lupus increases the risk of cancer, especially of non-Hodgkin's lymphoma, lung cancer, and liver cancer
- Bone tissue death – a lower blood supply to bone tissue leads to tiny breaks and eventual death of bone. This is most common in the hip bone.
- Pregnancy – lupus increases the risk of miscarriage, hypertension during pregnancy, and preterm birth.