Background

• Leprosy is a chronic mycobacterial disease of the skin, the peripheral nerves and upper airway mucous membranes. The disease is transmitted mainly through airborne spread from nasal secretions of patients infected by Hansen’s bacillus (Mycobacterium leprae) and also through inoculation into broken skin. Leprosy is endemic in several tropical areas around the world, including Africa.
• Patients are classified into two groups, depending on presence of skin and nerve signs:
  • Multibacillary patients (MB) with more than 5 skin patches and several nerve enlargements.
  • Paucibacillary patients (PB) with one to five skin patches and a single nerve enlargement.
• Leprosy control has improved greatly through use of WHO recommended multidrug therapy (MDT). MDT combining two or three drugs (rifampicin, clofaximine and dapsone) is very effective in curing leprosy. At the end of 1999, leprosy point prevalence in African countries was 1.6 cases per 10 000 population with about 70 000 registered cases. Seventeen years later, at the end of 2016, this prevalence rate was reduced to 0.25 cases per 10 000 population and less than 25 000 registered cases
• Incubation period is 6 months to 20 years or more. Infection is probably frequent but clinical disease is rare, even among the closest contacts of patients. Multibacillary patients are most contagious, but infectiousness is reduced rapidly as soon as multiple drug therapy begins. Leprosy can be complicated by neuritis and leprosy reactions, resulting in impairment and disabilities of hands, feet, and eyes.
• Leprosy has historically been associated with social isolation and psychosocial consequences. This social stigma still persists in some countries in Africa.
• Some skin diseases such as tinea versicolor, mycosis, vitiligo, Scleroderma, psoriasis, systemic lupus erythematosus and Von Recklinghausen disease may be mistaken for leprosy.