Cutaneous leprosy, also known as Hansen's disease, is a chronic infection caused by the bacterium Mycobacterium leprae. It primarily affects the skin and peripheral nerves. Animals like armadillos and chimpanzees can also be infected. The disease progresses slowly and symptoms may not appear for years. Initial lesions often appear as pale patches on the skin in cooler areas of the body. A definitive diagnosis is made based on skin lesions, nerve thickening, and loss of sensation. Leprosy is classified based on clinical features and response to treatment involves multidrug therapy administered for 6-12 months depending on a patient's classification.