Olfactory Dysfunction in Leprosy

Abstract

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.

Olfactory Dysfunction and Olfactory Bulb Volume Reduction in Patients with Leprosy

“…Although nasal pathology is common in leprosy, few studies have examined changes to the sense of smell in this patient group [1,16]. Olfactory system dysfunction and anosmia have been observed in all types of leprosy, but no study has investigated the underlying physiopathology.…”

“…The OB is a neuroplastic structure and its size may change in relation the level of afferent neural activity [1]. Although nasal pathology is common in leprosy, few studies have examined changes to the sense of smell in this patient group [1,16].…”

“…Furthermore, the number of patients who lose the function of smell is not known. Chaturvedi et al [14] reported olfactory dysfunction in approximately 40% of patients with leprosy, Ozturan et al [16] reported that the rate was 91%, and Mishra et al [1] observed olfactory dysfunction in all leprosy cases.…”

“…Few studies of olfactory dysfunction in leprosy have been published in the English medical literature [1,[14][15][16]. Furthermore, the number of patients who lose the function of smell is not known.…”

“…Leprosy, also known as Hansen's disease, is a chronic granulomatous infection caused by Mycobacterium leprae [1]. M. leprae, primarily affects the skin, eyes, peripheral nerves, and testes and tends to spread to the ears, nose, upper aerodigestive system, hands, and feet [2].…”