Leprosy in the 21st century

Abstract

Despite significant improvements in leprosy (Hansen's disease) treatment and outlook for patients since the introduction of multidrug therapy (MDT) 3 decades ago, the global incidence remains high, and patients often have long-term complications associated with the disease. In this article, we discuss recent findings related to genetics, susceptibility, and disease reservoirs and the implications of these findings for Hansen's disease control and health outcomes for patients. We describe the continued difficulties associated with treatment of inflammatory episodes known as "leprosy reactions," which cause much of the disability associated with the disease and can affect people for many years after MDT is complete. We also discuss some of the contemporary challenges for physicians and patients, including international and internal migration of people affected by the disease. We suggest some important areas of focus for future Hansen's disease research.

FIG 1

A 23-year-old female with the tuberculoid leprosy form, manifesting as a single well-defined hypopigmented macular lesion associated with anesthesia.

FIG 2

A 42-year-old male with borderline tuberculoid leprosy, manifesting as multiple (>5) polymorphic, partially raised, confluent, hypopigmented macules associated with anesthesia. The patient also had irregular enlargement of several large nerves in an asymmetrical pattern.

FIG 3

A 53-year-old male with the borderline borderline form of leprosy, manifesting as multiple infiltrated plaques with punched-out centers associated with anesthesia. The patient had many nerves involved in a symmetrical pattern.

FIG 4

A 29-year-old male with the borderline lepromatous form of leprosy, presenting with diffuse thickening of the skin with associated anesthesia and paresis.

FIG 5

A 17-year-old male with the lepromatous leprosy form of leprosy, manifesting as diffuse thickening with innumerable discrete as well as confluent nodules.

FIG 6

A 38-year-old male with a type 1 reaction with acute inflammation of existing plaques. (Adapted from reference .)

FIG 7

Histopathological progression of cutaneous lesions in type 1 reactions. (A) The initial skin biopsy specimen revealed features of borderline lepromatous leprosy, with a disorganized inflammatory infiltrate in which vacuolated macrophages predominated. Occasional multinucleated giant cells were also noted. Fite stains revealed moderate numbers of bacilli (inset and thin bold arrow). (B) A biopsy specimen 1 month later revealed greater organization of the inflammatory infiltrate and increased lymphocytic clustering, with more numerous multinucleated giant cells, consistent with a type 1 leprosy reaction (thick dotted arrow) (original magnification for photographs of hematoxylin- and eosin-stained sections, ×250; original magnification for photographs of Fite-stained sections, ×1,000). (Adapted from reference by permission of Oxford University Press and the Infectious Diseases Society of America.)

FIG 8

A 51-year-old male with erythema nodosum leprosum, manifesting as newly appearing red, painful, tender red papules and nodules in crops in the extensor surface of the arm.

FIG 9

Erythema nodosum leprosum. Several polymorphonuclear cells are seen (top left, thick bold arrow) against a background of foamy histiocytes (seen best at the bottom right [thin dotted arrow]) (hematoxylin and eosin staining; original magnification, ×400).