The causes of lupus are complex and not yet fully understood. Lupus is a multifactorial autoimmune disease, meaning it arises from a combination of genetic, hormonal, environmental, and immunological factors. No single cause is responsible for lupus; rather, it develops through an interplay of multiple influences — especially in individuals with a genetic predisposition.
Understanding what causes lupus is critical for early detection, effective management, and prevention of disease flares.
1. Genetic Predisposition
Genetics play a key role in lupus risk. While lupus is not directly inherited, people with a family history of lupus or other autoimmune diseases have a higher likelihood of developing it.
Several gene variants linked to the immune system — including HLA-DR2 and HLA-DR3 — are associated with lupus. These genes are involved in regulating inflammation and antibody production. However, carrying these genes does not guarantee the development of the disease, highlighting the importance of external triggers.
2. Hormonal Influences
Lupus is far more common in women, especially those of childbearing age, which suggests a strong hormonal component — particularly the role of oestrogen. Many women report flares during:
- Menstrual cycles
- Pregnancy
- Use of hormonal contraceptives
Although hormones are clearly involved, the exact mechanism by which they influence lupus remains under investigation.
3. Environmental Triggers
Several environmental factors can trigger lupus in genetically susceptible individuals:
• Sunlight (Ultraviolet Radiation)
Exposure to UV rays can:
- Trigger lupus flares
- Cause photosensitive rashes
- Possibly initiate the onset of lupus in individuals without prior symptoms
• Infections
Viral infections, especially Epstein-Barr virus (EBV), are believed to play a role. Infections may cause the immune system to mistake the body’s own tissues for pathogens — a process known as molecular mimicry.
• Medications
Certain drugs can lead to drug-induced lupus erythematosus (DILE). Common culprits include:
- Hydralazine
- Procainamide
- Isoniazid
- Some anti-seizure medications
Drug-induced lupus often mimics systemic lupus erythematosus (SLE) but is usually milder and resolves once the drug is discontinued.
• Smoking
Tobacco use has been linked to both the development and worsening of lupus. Smoking:
- Alters immune function
- Increases oxidative stress
- Reduces treatment effectiveness
• Toxic Exposures
Prolonged contact with substances such as:
- Silica dust
- Mercury
- Agricultural pesticides
…has been associated with a higher risk of lupus and other autoimmune diseases. However, more research is needed to establish firm connections.
4. Stress and Trauma
Both emotional and physical stress may contribute to the onset or flare-up of lupus. While stress is not a direct cause, it may:
- Disrupt hormonal balance
- Suppress immune regulation
- Trigger inflammation
Events like major surgery, emotional trauma, or the loss of a loved one are commonly reported as flare triggers.
5. Vitamin D Deficiency
Vitamin D is essential for healthy immune function. Many lupus patients are found to have low vitamin D levels, possibly due to:
- Avoidance of sun exposure
- Chronic inflammation
Whether deficiency is a cause or result of lupus is unclear, but vitamin D supplementation may offer immune-modulating benefits.
6. Ethnicity and Genetic Risk
Lupus is more prevalent in certain ethnic groups, including:
- African
- Asian
- Hispanic
- Native American populations
This suggests a combination of genetic susceptibility and environmental or socioeconomic factors may influence disease development and severity.
7. Type-Specific Causes of Lupus
Different types of lupus may have unique causes:
• Cutaneous Lupus
Often triggered or worsened by sun exposure and associated with specific genetic markers.
• Neonatal Lupus
Caused by the transfer of maternal autoantibodies (especially anti-Ro and anti-La) to the fetus. Most cases resolve within the first few months of life, although rare complications like congenital heart block can occur.
• Drug-Induced Lupus
Linked directly to specific medications, usually with milder symptoms and fewer long-term complications than systemic lupus.
Summary: What Causes Lupus?
The causes of lupus are multifactorial and include:
- Genetic predisposition
- Hormonal imbalances
- Environmental exposures (e.g., UV light, viruses, toxins)
- Immune system dysfunction
- Lifestyle factors (e.g., smoking, stress)
Understanding these risk factors is key to prevention, early diagnosis, and personalised treatment planning. While science continues to explore the underlying mechanisms of lupus, individuals at risk can reduce flare likelihood by:
- Avoiding triggers
- Maintaining a healthy lifestyle
- Seeking regular medical care
