Characteristics of Drug-Induced Lupus Erythematosus

Systemic lupus erythematosus, often abbreviated SLE, is a serious autoimmune syndrome that usually affects young women. Most lupus is idiopathic, which means that its cause is unknown, but approximately 10% is associated with the use of specific drugs (Adams and Hess 1991). The diagnosis of drug-induced lupus is made on the same basis as idiopathic lupus; in addition, the symptoms must have begun after initiation of treatment with a drug and must resolve on discontinuation of that drug treatment. Although the signs and symptoms of drug-induced lupus overlap with those of idiopathic lupus and the two syndromes cannot be differentiated on the basis of differences in signs and symptoms, the usual clinical picture is somewhat different.A significant difference is that drug-induced lupus is usually milder, and the most serious manifestations of idiopathic lupus are usually absent in the drug-induced variety. Despite the overlap in symptoms between idiopathic and drug-induced lupus, the differences suggest that their pathogenic mechanisms are different. In addition, drugs associated with the induction of lupus do not usually exacerbate idiopathic lupus (Reza et al. 1975), and the genetically associated risk factors are different for the two syndromes, as described below. Therefore, it is probably more accurate to call the drug-induced variety a drug-induced lupus-like syndrome. However, the pathogenic mechanisms of both are unknown, and even in idiopathic lupus the mechanisms may be significantly different in different patients. Therefore, until we know more about the mechanism of both syndromes, it is reasonable to use the term “drug-induced lupus”.