Systemic lupus erythematosus (also known as SLE or lupus) is an inflammatory multi-system disease of unknown etiology. It is recognized worldwide and more prevalent in women, especially in their reproductive years.
This effect of age and sex on incidence and prevalence rates of SLE suggests a role for hormonal factors in its pathogenesis. There are also differences in how common the disease is among different ethnic groups. In the USA, for example, SLE is three times more common among African-Americans than Caucasians. Genetic factors have long been considered to have a role in the formation of SLE. There are observations of a higher prevalence of SLE among twins.
SLE generally has a variable clinical course, depending on the symptoms and organs that are involved. The clinical picture of SLE can also change over time, in terms of both disease activity and organ involvement. The pathogenesis is complex and parallels the wide variation in clinical symptoms. As a result, patients can often go months or years without having a proper diagnosis. No single mechanism of action applies to all cases and the initial triggering events remain largely unknown.
Symptoms
SLE can affect any organ in the body, but most commonly affects the skin, joints, kidneys, lungs, nervous system, and serous membranes (lining of the lungs, heart, and abdomen). Immune system abnormalities, especially the production of specific antibodies, are another prominent feature of the disease.
Most patients with lupus have mild-to-moderate disease with chronic smoldering symptoms, punctuated by gradual or sudden increases in disease activity (flare-ups). The disease course in a smaller percentage of patients is characterized by alternating flare-ups and complete clinical remissions. Rarely, a patient has a single episode of active SLE followed by sustained remission.
Diagnosis
Due to the wide variation in symptoms and organs that can be affected. lupus can be quite difficult to diagnose. The diagnosis is made clinically and depends on a combination of symptoms, physical exam, labs, and any other diagnostic tests/imaging.
In almost all patients with SLE, however, there is a positive antinuclear antibody (ANA). This lab finding can be seen in up to 8% of the general population without any symptoms or autoimmune diseases, so having a positive ANA on its own does not mean you have lupus. Other conditions, such as thyroid disease, cancer, and infection can also lead to this positive lab result. As, a result, having a positive ANA is very nonspecific and must be interpreted in the context of your symptoms and other relevant labs.
Given the varied clinical presentations of SLE patients, in 2019, the American College of Rheumatology created a new set of classification criteria for SLE patients to help enroll in clinical trials. These criteria are only meant for research purposes but provide a useful framework for understanding common symptoms in SLE patients. Some of these symptoms are listed below:
- Fever
- Nonscarring hair loss
- Sores inside of the mouth and/or the nose
- Rashes
- Fluid around the heart and/or lungs, leading to pain or difficulty breathing
- Joint pain
- Blood in the urine
- A higher risk or history of blood clots or miscarriages
Treatment
The management of patients with lupus is decided on an individual basis, guided by the degree and severity of specific symptoms and organ involvement. Most patients, regardless of the symptoms and organs that are involved, should be on a medication called hydroxychloroquine. This medication helps to decrease flares of disease and maintain remission in lupus patients.
Preventive strategies for decreasing SLE flare-ups are recommended for most patients. These include:
- Avoid ultraviolet light exposure by using sunscreen, staying out of the sunlight as much as possible, and wearing sun-protective clothing.
- Avoid exercising to exhaustion. Extreme physical efforts can trigger increased lupus activity.
- Avoid infections. Many common respiratory infections can trigger increased lupus activity and can be prevented by frequent washing of the hands and other simple hygiene measures.
- Avoid possible disease triggers, which can include sulfa antibiotics, high-estrogen birth control pills, prolonged sun exposure, and certain foods (such as alfalfa sprouts).
Pregnancy may entail a slightly increased risk of a lupus flare-up. Also, breast-feeding may increase the risk of a postpartum flare-up.
If you think you might have lupus, it is very important to see a rheumatologist for proper diagnosis and treatment. Because of the myriad of different ways a patient with SLE may present, it is important to see a specialist who is trained in its diagnosis and management. SLE, if left untreated, can be life-threatening in certain cases and can increase the risk of heart attacks, strokes, blood clots, and decrease life expectancy.
