American Board of Internal Medicine (ABIM) Certification Practice Exam

When is the diagnosis of drug-induced lupus erythematosus typically confirmed?

1. After one month of treatment

2. When symptoms worsen

3. When symptoms resolve several weeks to months after discontinuation of the offending agent

4. Immediately after stopping the medication

The correct answer is: When symptoms resolve several weeks to months after discontinuation of the offending agent

The diagnosis of drug-induced lupus erythematosus is typically confirmed when symptoms resolve several weeks to months after discontinuation of the offending agent. This approach to diagnosis hinges on the characteristic temporal relationship between the exposure to the drug and the emergence or exacerbation of lupus-like symptoms, such as joint pain, skin rash, and serositis. Once the suspected drug is eliminated and if the symptoms begin to subside, it strongly points towards the diagnosis of drug-induced lupus. The time frame for resolution is important, as true drug-induced lupus often shows improvement after the offending medication is discontinued, but it typically does not resolve immediately. Observing significant improvement after a few weeks to months provides crucial evidence supporting the diagnosis. This period allows for the body to clear the drug and the immune response to settle down. The other options do not align with the standard understanding of diagnosis in this context. For instance, confirming a diagnosis immediately after stopping a medication would not account for the time needed for symptoms and observational changes to develop. Similarly, waiting for symptoms to worsen does not aid in diagnosis; the assessment focuses on resolution rather than exacerbation. Finally, confirming the diagnosis after just one month of treatment does not provide adequate assurance, as symptoms may not show definitive patterns