Olfactory dysfunction in leprosy.

Leprosy (Hansen's disease) is associated with a high incidence of nasal pathology. Despite this fact, the influence of this disorder on the sense of smell is poorly understood. In this study, we administered a standardized 12-item odor identification test to 77 patients with three types of leprosy: tuberculoid (n = 9), borderline (n = 42), and lepromatous (n = 26). All three types exhibited significantly lower test scores than their respective age-, sex-, and smoking-habit-matched controls. Patients with lepromatous leprosy exhibited significantly lower test scores than those with the other two types. Only patients with lepromatous leprosy exhibited meaningful improvement in smell function after treatment. No association between disease duration, per se, and the severity of the olfactory deficit was present. Overall, 100% of the patients exhibited olfactory dysfunction, suggesting that earlier prevalence estimates based on nonstandardized olfactory testing have underestimated the prevalence of this problem.