Autoimmune diseases occur when the body is triggered to see its own organs or tissues as foreign, and so the immune system attacks them. In rheumatoid arthritis it’s mainly the joints. And in lupus it’s the skin, and many other organs including the brain.

Early treatment is crucial, so research by an international team led by scientists at Cambridge University and King’s College London is intriguing.

They’ve uncovered an early warning system in the form of nightmares and hallucinations – or “daymares” – which may herald the onset of autoimmune diseases such as lupus.

Researchers surveyed 676 people living with lupus and 400 doctors, as well as carrying out detailed interviews with 69 people living with autoimmune rheumatic diseases, including lupus.

In the study, the team asked patients about the timing of 29 neurological and mental health symptoms (such as depression, hallucinations and loss of balance). In interviews, patients were asked if they could list the order that symptoms usually occurred when their disease was flaring. One of the more common symptoms reported was disrupted dream sleep, ­experienced by three out of five patients, a third of whom reported this symptom appearing over a year before the onset of lupus.

They found that three in five lupus patients and one in three with other rheumatology-related conditions reported increasingly disrupted dreaming sleep – usually vivid and distressing nightmares – just before their hallucinations.

These nightmares often involved being attacked, trapped, crushed, or having a sensation of falling. Using the word “daymares” to talk about hallucinations often helped patients open up as it’s a less ­frightening word.

They agree recognising these flare symptoms may provide an “early warning system” enabling them to improve care and even reduce clinic times by averting flares at any earlier stage.

Senior study author Professor David D’Cruz from Kings College London said: “For many years, I have discussed nightmares with my lupus patients and thought that there was a link with their disease activity.

“This research provides evidence of this, and we are strongly encouraging more doctors to ask about nightmares and other neuropsychiatric symptoms – thought to be unusual, but actually very common in systemic autoimmunity – to help us detect disease flares earlier.”

Professor Guy Leschziner, a study author from Guy’s and St Thomas’ hospital, said: “This is the first evidence nightmares may also help us monitor such a serious autoimmune condition like lupus, and is an ­important prompt to patients and clinicians alike that sleep symptoms may tell us about impending relapse.”