The Sense of Smell in Systemic Lupus Erythematosus

Objective. To assess the olfactory functions in systemic lupus erythematosus (SLE) patients compared with age- and sex-matched healthy controls, and to examine the association between the sense of smell and disease activity and central nervous system (CNS) involvement. Methods. Olfactory functions in 50 SLE patients and 50 age- and sex-matched controls were evaluated using the Sniffin' Sticks test, the 3 stages of which are threshold, discrimination, and identification (TDI) of different odors. TDI scores were analyzed according to SLE disease activity and CNS involvement. Results. In both the SLE and control groups, smell deficit correlated with male sex and older age. A decrease in the sense of smell was observed in SLE patients (46%) and controls (25%) (P <= 0.02), while loss of smell (anosmia) was documented only in SLE patients (10%). Total TDI scores and individual stages of smell correlated with SLE Disease Activity Index (P < 0.001) and CNS manifestations (P < 0.03). Conclusion. Our findings suggest that there is a decrease in the sense of smell in SLE patients compared with healthy subjects and that the decrease in the sense of smell among SLE patients correlates with disease activity and CNS involvement.