Why do I have lupus?
This common question is difficult to answer with certainty. However, in recent years we have increased our understanding of why someone develops lupus. It appears that the genes we inherit from our parents are responsible for some of the risk. In addition, the environment around us also plays an important role. Environmental factors that have been linked to lupus include exposure to sunlight, viruses and silica dust.
Different environmental factors may increase the risk of developing lupus. However, these will only be important in someone who may already have inherited lupus genes.
Key points
Triggering factors can include:
• UV light
• Stress
• Viral infections
Sunlight
Ultraviolet light that is present in sunlight can have two effects on lupus. Firstly, it can make lupus skin rashes worse. Secondly, it also appears to cause a more general flare of lupus in certain people. One piece of research work supporting this idea comes from Scandinavian countries that have a very big difference in seasonal exposure to sunlight. For example, people living near the Arctic Circle have summers that are light for nearly 24 hours per day and winters that are dark for nearly 24 hours per day. In these populations a lupus flare becomes more likely after sun exposure in the summer.
Smoking
Smoking has many negative effects on health. However, in recent years researchers have started to believe that smoking makes diseases like lupus and rheumatoid arthritis more severe. It may be that smoking stimulates the immune system to become more aggressive and begin the process that ends in lupus. It is also very relevant that smoking impairs the beneficial effects of Plaquenil®.
Silica
Silica is a mineral that most people encounter as quartz on beaches or rocky outcrops. People who are exposed to silica dust, such as miners, stonemasons and sand blasters, are more likely to get lupus. The silica appears to stimulate the immune system. Clearly most people are not exposed to industrial silica dust, but perhaps lower levels may also produce some effects in certain individuals.
Viruses
Some common viruses have been linked to lupus. All of us are exposed to many different viruses during our lives. However, some individuals, perhaps those with the lupus genes, may over-react to them. The Epstein-Barr virus (EB) is responsible for causing infectious mononucleosis, more commonly known as glandular fever. There is increasing evidence that the EB virus may be one of the environmental factors that makes lupus more likely.
Lupus occurs when a patient's blend of genes, and environmental factors come together. Rather like being dealt a bad hand in a card game, it is not the individual card but the whole hand of cards that causes the problem. The world around us contains viruses, sunlight, dust, and many other factors. Some of these seem to be important in causing lupus to flare.