Symptoms Of DILE
- People with drug-induced lupus most often complain of flu-like symptoms, especially muscle and joint pain.
- Sometimes the symptoms appear gradually and worsen when the person is treated with the implicated drug for many months.
- In other people, the onset of symptoms is rapid.
- Features of drug-induced lupus are essentially the same regardless of the implicated medication. (However, there is some suggestion that certain symptoms are more common with particular drugs.)
- Symptoms are mild in most people, but can become debilitating if the individual continues to take the offending medication.
- By the time a diagnosis is made, most people will have one or more of these symptoms:
- - joint pain
- muscle pain
- inflammation of the heart and lung.
DILE Should Not Be Confused With Medication Side Effects
Drug-induced lupus should not be confused with the drug side-effects that often occur after short-term therapy for gastrointestinal, neurologic, or allergic symptoms. These problems usually occur within a few hours to days of taking the medication.
Drug-induced lupus typically comes after many months or years of continuous therapy with the causative drug.
Laboratory Testing For DILE
As with SLE, most people with drug-induced lupus develop antinuclear antibodies, or ANAs, although those with a form of drug-induced lupus related to quinidine often are ANA-negative. The ANAs in drug-induced lupus are primarily autoantibodies that are able to react with a histone-DNA complex, which is the major component of the nucleus of all cells.
A special laboratory test to detect certain antibodies to this histone-DNA complex is a sensitive marker for lupus-like disease brought on by many drugs. Hydralazine is the exception, as only about one-third of people with DILE have this type of anti-histone antibody.
- Although the ANA or anti-histone test can help to confirm a diagnosis of DILE, it is not useful to periodically test people who have no symptoms.
- Most medications with a tendency to induce lupus-like disease also produce (at a much higher frequency) a mild type of anti-histone antibody not associated with symptoms.
- There is no evidence that people who develop only ANA without symptoms are at increased risk for future development of DILE symptoms.