Drug-induced lupus: symptoms, causes and what happens next

Lupus (systemic lupus erythematosus) is an autoimmune condition in which the immune system attacks healthy parts of the body. The NHS says it is a long-term condition that causes joint pain, skin rashes and tiredness. Drug-induced lupus is a related but distinct problem: lupus-like symptoms appear as a reaction to a medicine rather than as a lifelong autoimmune disease.

Patient.info lists minocycline, an antibiotic often used for acne, and hydralazine, a blood pressure medicine, as examples of medicines that can cause it. The pages read for this guide do not give a full list of implicated medicines, so the person prescribing your medicines or your pharmacist is the best source of information on a specific drug.

Because the illness is triggered by an exposure, it differs from systemic lupus in an important way: removing the trigger usually allows it to settle.

Drug-induced lupus shares features with ordinary lupus. The NHS lists the main symptoms of lupus as joint and muscle pain, extreme tiredness that will not go away no matter how much you rest, and rashes that usually come on after being in the sun, often over the nose and cheeks. Other possible symptoms include headaches, mouth ulcers, a high temperature, hair loss, weight loss, swollen glands, depression and anxiety, chest or tummy pain, and colour changes in the fingers and toes in the cold (Raynaud's).

Not everyone with the drug-induced form will have all of these. Patient.info notes that drug-induced lupus tends to be milder than other forms, which in practice means that joint and muscle aches, tiredness and a low-grade fever are the more usual complaints than serious organ involvement.

• Aching joints and muscles.

• Persistent tiredness, or a mild raised temperature.

• A rash, which may be worse after sun exposure.

• Symptoms that began some time after starting a new long-term medicine.

The NHS notes that lupus is not always easy to diagnose because the symptoms can be similar to other conditions, and that a GP will usually do blood tests, which may show high levels of a certain type of antibody, together with the typical symptoms. Further tests such as scans may be arranged if organs might be affected.

With a suspected drug reaction, the doctor will also review your medicines and the timing of symptoms. Telling your GP exactly which medicines you take, and when each was started, is the most useful thing you can bring to the appointment.

This guide has not drawn on a UK source that sets out the detailed antibody patterns used to separate drug-induced from systemic lupus, so it does not describe them. If you need that detail, ask your rheumatologist.

Versus Arthritis says drug-induced lupus usually gets better when people come off the medication that caused it, and Patient.info says it usually resolves once the medication is stopped. This is the central difference from systemic lupus, which the NHS says has no cure although symptoms can improve with treatment.

The decision to stop or swap a medicine belongs with the prescriber, because the medicine may be treating something important such as high blood pressure, infection or acne, and an alternative has to be chosen. Simple measures from the NHS lupus advice, such as sun protection with high-factor sunscreen, pacing yourself and staying active, may help while symptoms settle.

If symptoms do not improve after the medicine has been stopped, or if there are signs of organ involvement, ask for a review, because the problem may be systemic lupus rather than a drug reaction.

The NHS advises seeing a GP if you often get symptoms of lupus, because it is better managed if found and treated early. If you have chest pain, difficulty breathing or any sudden severe symptom, treat it as an emergency and use NHS 111, or call 999 if it is severe. Report suspected side effects to your prescriber or pharmacist, and you can also report them through the Yellow Card scheme.

On the NHS the pathway usually starts with the GP, who reviews medicines and arranges blood tests, with referral to rheumatology if lupus is suspected. A private rheumatology appointment can speed up assessment, but changes to long-term medicines should still be coordinated with whoever prescribes them.