For some people with lupus, certain environmental factors, such as heat and UV light from the sun, may trigger a flare-up of symptoms.

Lupus is an autoimmune condition that can affect many areas of the body.

Autoimmune conditions occur when a person’s immune system mistakenly attacks healthy tissues. This can result in inflammation, which in some cases may cause permanent tissue damage. Certain triggers may lead to symptom flares.

This article discusses the effect of heat on lupus, including how UV radiation from the sun may affect people with the condition. It also explores heat therapy and when to contact a doctor.

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The Lupus Foundation of America estimates that lupus affects approximately 1.5 million people in the United States and at least 5 million people worldwide. It states that the most common type of lupus is systemic lupus erythematosus (SLE), accounting for roughly 70% of all cases.

A person with lupus may find that their symptoms flare up in the presence of certain triggers, which may include:

Research from 2020 looked into the effect of various environmental factors on SLE symptoms in 1,261 people with the condition. The researchers found that increases in temperature were associated with:

They also noted that temperature increases were marginally associated with reduced flares involving the kidneys.

Additionally, the researchers stated that high body temperature can affect a person’s immune system, causing an increase in white blood cells and antibodies. Since lupus is an autoimmune condition, an increase in immune system activity may worsen symptoms.

However, the researchers noted that the effects of environmental temperature on immune response are unknown, and further research into the topic is necessary.

UV radiation

UV radiation can come from the sun or some artificial sources, including tanning beds. Without protection, such as sunscreen, exposure to UV radiation may cause a person to develop sunburn or skin cancer.

According to the Lupus Foundation of America, 40–70% of people with lupus may be sensitive to UV radiation.

It explains that the process through which the immune system removes any cells damaged by UV radiation can take much longer in people with lupus. A buildup of these damaged cells can trigger an immune reaction, leading to a flare-up of lupus.

This may be why some people find that their symptoms worsen in the summer months when they are more exposed to heat and UV radiation from the sun.

UV radiation may cause a person with lupus to experience:

The Lupus Foundation of America suggests that applying heat to painful areas may help with lupus symptoms. It suggests taking a hot bath or shower or applying a warm towel to the area. However, no concrete evidence suggests that heat therapy can specifically help with lupus pain.

In addition to heat therapy, some people may try alternative therapies to help treat lupus symptoms, such as:

It is important to note that the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) notes that no definitive evidence suggests these treatments benefit a person with lupus.

It is best for a person to speak with their doctor before trying any alternative treatments for lupus. Additionally, a person should not stop taking any prescription medications without checking that it is safe to do so with their doctor.

A literature review from 2019 suggests that exercise and psychological treatments, such as cognitive behavioral therapy, could help reduce certain lupus symptoms when a person uses them alongside medications.

However, the researchers noted that the studies included in the review had small sample sizes and short durations. They concluded that further research is required to confirm the findings.

The NIAMS notes that a person who has lupus will need to see their doctor frequently to monitor their symptoms. A doctor can also advise on how best to manage symptoms. Management techniques may include:

  • medications
  • specific exercises
  • eating a healthy diet
  • quitting smoking, if applicable
  • applying sunscreen regularly when outdoors and using other protective methods when needed, such as wearing a long-sleeved shirt and a hat
  • managing stress levels as much as possible

A doctor may also help a person identify their lupus triggers. They may ask the person to keep a journal detailing how they felt and what they were doing when symptoms developed.

Lupus is an autoimmune condition. A person may experience a flare-up of lupus symptoms when exposed to certain triggers, including heat and UV radiation. However, scientists are still unsure about whether external temperature affects lupus.

Some people may try heat therapy to soothe pain from lupus flares. However, there is no definitive evidence to suggest heat therapy is a suitable treatment for lupus pain.

A person who has lupus will need regular checkups with their doctor. They can help to monitor a person’s condition and provide appropriate treatments. A doctor may also be able to help a person determine lupus symptom triggers.