What complications can lupus cause?

Without treatment, lupus most often progresses gradually: the immune system remains abnormally active and maintains ongoing inflammation throughout the body. Over time, this inflammation can weaken certain organs, particularly the kidneys, the heart and its blood vessels, the lungs, and the nervous system. Flares then tend to become more frequent, while periods of remission become shorter, increasing the risk of lasting damage.

In contrast, when a treatment is initiated, the progression is generally better controlled. The goal is not to make the disease disappear but to stabilize it: to reduce the intensity of flares, protect the organs, and maintain the best possible quality of life. Even in this context, lupus remains a condition that requires monitoring, because it can become active again after a quiet phase, and certain complications may appear in the long term.

The manifestations of lupus can vary greatly from one person to another. Some complications are common, while others are rarer but potentially serious.

Cutaneous complications of lupus

Systemic lupus can cause permanent skin complications that affect appearance and quality of life. These complications occur mainly after repeated or chronic lesions, and require particular attention for their prevention and monitoring.

Alopecia and scarring or depigmentation

Scarring alopecia corresponds to an irreversible loss of hair in certain areas, often following severe skin lesions. Scars and depigmented patches can also appear as a result of chronic eruptions or repeated inflammatory lesions. These complications result from prolonged inflammation and destruction of hair follicles or skin tissues by autoantibodies, often worsened by sun exposure. Scarring alopecia affects about 5 to 15% of patients, while severe scarring or depigmentation occurs in 10 to 20% of patients with chronic skin lesions. Once established, these lesions are difficult to reverse.

A longitudinal study conducted on 420 patients with lupus showed that scarring alopecia affected about 12% of patients over a 10-year period. Severe skin scarring and depigmentation occurred mainly in patients who had chronic and recurrent skin lesions, confirming that persistent inflammation and untreated skin lesions are key factors in the development of these complications.

Squamous cell carcinoma.

Squamous cell carcinoma is a type of skin cancer that originates in the squamous cells of the epidermis. It generally develops as a result of repeated damage caused by UV radiation, particularly from the sun, which alters the DNA of skin cells and promotes the appearance of mutations that can trigger a cancerous process.

Individuals with fair skin, who are more sensitive to the effects of sunlight, are about 1.5 to 2 times more likely to develop this type of lesion than people with dark skin.

It is important to note that in patients with lupus, the risk of developing a squamous cell carcinoma is slightly increased. However, the disease itself is not, on its own, a determining factor. Other elements are involved, such as excessive sun exposure, smoking, certain viral infections, and the presence of chronic skin conditions. Thus, even though particular vigilance is recommended in people with lupus, the overall level of risk remains moderate.

Infectious complications.

Complications related to infections represent one of the main causes of morbidity and mortality in patients with lupus. They result both from the disease itself and from the treatments used to control it. From a biological standpoint, lupus causes an intrinsic disruption of the immune system. Specifically, there is dysfunction of B and T lymphocytes, an ineffective production of protective antibodies, and altered use of complement, which plays a key role in the clearance of pathogens. In addition to this vulnerability, immunosuppressive treatments, corticosteroids, and biotherapies further diminish the body’s defense mechanisms by dampening the immune response.

These mechanisms promote different types of infections. Bacterial infections are the most common, particularly respiratory and urinary infections. Viral infections, such as herpes reactivations, and opportunistic infections (tuberculosis, fungal infections), occur more frequently in patients with severe immunosuppression. Some studies report that nearly 50% of patients experience at least one significant infectious episode. Furthermore, infections are involved in up to 30 to 50% of lupus-related deaths, especially in the first few years after diagnosis.

Pregnancy-related complications.

Pregnancy in a patient with lupus represents a particular situation, in which immunological and hormonal changes can influence the course of the disease and lead to specific complications. The origin of these complications is based on a complex interaction between lupus activity, maternal autoantibodies, and the physiological adaptations of pregnancy. Certain autoantibodies, particularly antiphospholipid antibodies and anti-SSA/Ro and anti-SSB/La antibodies, can cross the placental barrier and interact with fetal tissues or the placental vascular system. In addition, the treatments used, especially corticosteroids, can also play a role by increasing the risk of gestational diabetes, because they reduce the sensitivity of cells to insulin and stimulate glucose production by the liver, thereby leading to an increase in blood sugar levels.

From a mechanistic standpoint, antiphospholipid antibodies promote the formation of microthromboses in the placenta, impairing exchanges between the mother and the fetus. This can lead to placental insufficiency. Anti-SSA/SSB antibodies, for their part, can target the fetal cardiac conduction system, resulting in arrhythmias. These mechanisms give rise to various types of complications. In the mother, there is an increased risk of lupus flares in approximately 25 to 50% of pregnancies, as well as hypertension in 10 to 20% of patients and preeclampsia in 5 to 15%. On the fetal side, complications may include miscarriages in 15 to 25% of cases, intrauterine growth restriction in 10 to 20%, preterm birth in 20 to 30% of pregnancies, and, more rarely, neonatal lupus with cardiac involvement.

Kidney involvement.

Kidney nephropathy is a common phenomenon in systemic lupus erythematosus (SLE), and it has a major impact on both functional outcomes and survival. Several types of lesions can develop in the kidney. The most frequent involve the glomeruli (the kidney’s small filters), but other structures can also be affected. However, the most common manifestation remains lupus glomerulonephritis (GN). The intrarenal lesions that are observed are associated both with glomerular deposits of immunoglobulins and complement and with infiltration of kidney tissue by inflammatory cells, particularly activated macrophages. Anti–double-stranded DNA antibodies are linked to the onset of glomerular damage, but the autoantibodies that appear to be largely directly responsible for this kidney disease are anti-nucleosome antibodies. The process may be silent at first, before becoming apparent through proteinuria, hypertension, or progressive kidney failure.

Without treatment, persistent inflammation can lead to irreversible fibrosis of the kidney.

Data from longitudinal cohorts indicate that approximately 10% of patients with lupus nephritis progress to end-stage renal disease. Furthermore, numerous studies have shown that the intensity of immune complex deposition and complement activation are directly linked to renal prognosis, confirming the central role of these mechanisms in disease progression.

There are several forms of lupus nephritis, classified from I to IV according to their severity, ranging from mild forms to severe involvement that can lead to kidney failure.

Cardiovascular disorders.

Cardiovascular complications related to lupus arise from a persistent, chronic inflammatory state. This inflammation, which is characteristic of the disease, gradually damages the vascular endothelium, the thin layer of cells lining the inside of blood vessels and representing the starting point of cardiovascular abnormalities. Several mechanisms account for these complications.

The production of autoantibodies and the formation of immune complexes lead to complement activation and the secretion of pro‑inflammatory molecules. This sequence promotes endothelial dysfunction, which is the first step toward atherosclerosis. Likewise, certain autoantibodies, such as antiphospholipid antibodies, induce a prothrombotic state. This disrupts normal coagulation mechanisms, which increases the risk of clot formation.

These processes lead to various forms of cardiovascular involvement. On the one hand, there are direct inflammatory conditions, such as pericarditis or myocarditis, and on the other hand, vascular complications related to atherosclerosis, including myocardial infarction and stroke. In addition, there are thromboembolic events, which are particularly frequent in patients with an associated antiphospholipid syndrome.

Cardiovascular risk is influenced by several patient profiles. It is higher in young individuals with active lupus, in patients with kidney involvement, and in those with long-term exposure to corticosteroids, which promote hypertension, lipid disorders, and diabetes.

Research in vascular immunology has also confirmed that chronic inflammation and complement activation accelerate arterial aging, a phenomenon sometimes referred to as premature atherosclerosis. These findings highlight the central role of systemic inflammation in the development of cardiovascular complications in lupus and explain why their prevention depends as much on controlling disease activity as on managing associated risk factors.

Lung involvement.

Pulmonary complications are diverse and include pleural diseases, interstitial lung diseases, vasculitis, pulmonary embolism, pulmonary hypertension, upper airway disorders, shrinking lung syndrome, and infections. Clinical manifestations can range from an absence of symptoms, as seen in mild pleural effusion or obstructive airway disease, to potentially life‑threatening conditions, such as acute lupus pneumonitis or diffuse alveolar hemorrhage. Lupus-related interstitial lung diseases and pulmonary hypertension tend to be milder and are generally associated with a relatively favorable prognosis.

Although pulmonary involvement is generally common in lupus, the heterogeneity of this disease and the rarity of individual complications make clinical trials difficult to conduct. Consequently, treatment usually relies on case series and anecdotal reports involving various immunosuppressive agents. Some of these immunosuppressive drugs, such as azathioprine, methotrexate, and cyclophosphamide, have also been associated with drug-induced lung injury.

Neurological involvement.

Neurological manifestations of lupus are among the most heterogeneous. They may result from several mechanisms, including inflammation of cerebral blood vessels, the formation of microthromboses related to antiphospholipid antibodies, or the direct action of autoantibodies on neurons. These mechanisms can lead to cognitive impairment, seizures, or strokes. Neurological forms affect a minority of patients; nevertheless, they can be severe.

The diagnosis of neurological involvement is complicated by non-specific and variable symptoms, requiring a thorough neurological examination, brain imaging, characterization of autoantibodies, and analysis of cerebrospinal fluid. Current therapeutic approaches include corticosteroids, immunosuppressive agents, and new biological treatments that target specific immune pathways. The management of neuropsychiatric symptoms, epileptic seizures, and neuropathic pain remains a particularly challenging aspect of care.

Studies suggest that certain autoantibodies, particularly those targeting neuronal receptors, can directly impair synaptic transmission. Other research has demonstrated a link between disease activity and abnormalities observed on brain imaging, suggesting a relationship between systemic inflammation and neurological involvement.

Hematologic complications.

Hematological complications of lupus are among the earliest manifestations of the disease. They can appear within the first years, sometimes even before the diagnosis is confirmed, which suggests that they may be an early sign of the disease. These disorders result from a dysregulation of the immune system leading to the production of autoantibodies directed against blood cells. These autoantibodies bind to red blood cells, white blood cells, or platelets, causing their premature destruction, mainly in the spleen and the reticuloendothelial system. In addition, in some cases, the bone marrow is affected, disrupting the normal production of blood cells.

Several types of involvement can be observed. Anemia is the most frequent, whether inflammatory or autoimmune hemolytic in nature. Leukopenia, particularly lymphopenia, indicates impairment of the immune system itself, while immune thrombocytopenia is associated with a risk of bleeding. Conversely, some patients may have a prothrombotic state, especially if they have antiphospholipid antibodies, creating a paradox between the risk of bleeding and the risk of thrombosis. These manifestations are more common in patients with significant systemic involvement or certain early severe forms.

Data from the literature confirm this trend. Several longitudinal studies have shown that hematologic abnormalities are not only common, but also correlated with disease activity, making them an indirect marker of severity. Furthermore, work in immunohematology has demonstrated the central role of autoantibodies and complement activation in cell destruction, supporting the hypothesis of a direct immune mechanism underlying these complications.

Lupus can have very different consequences depending on its type and how it progresses. Some complications are common and well controlled today, while others remain more serious. However, early, regular, and appropriate management can significantly reduce these risks and improve the long-term prognosis.

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