Drug-induced lupus associated with synthetic conjugated estrogens

To report a case of drug-induced lupus (DIL) in a patient taking Cenestin, a combination product of synthetic conjugated estrogens.

A 54-year-old white female presented with a 4 month history of bilateral arm pain that developed and progressively worsened after initiating Cenestin 0.625 mg daily. The patient's symptoms, findings on physical examination (eg, degenerative changes of the acromioclavicular joint), and laboratory test results (eg, antinuclear antibody titer 1-640 [normal <1-40]) were suggestive of DIL. Her symptoms rapidly resolved with discontinuation of Cenestin and promptly resumed with reinitiation of the drug. Laboratory test values also improved significantly with discontinuation of Cenestin. Based on these findings and the Naranjo probability scale score, this reaction was probably associated with Cenestin.

DIL differs from systemic lupus erythematosus in that it is caused by prolonged exposure at adequate doses to a drug rather than being an autoimmune reaction. The most commonly reported and studied medications are hydralazine, quinidine, and procainamide. Other medications have been associated with DIL; however, data are limited in these reports, especially with estrogen. There have been no previous reports in the literature of synthetic estrogen products associated with DIL.

A diagnosis of DIL can be very challenging to make, especially since there are no clear criteria on which to base it. While estrogen has rarely been reported to be associated with DIL, it may be considered as a possible cause.