Leprosy (Hansen disease) is caused by Mycobacterium leprae and presents with anesthetic skin lesions and peripheral nerve complications. This chronic disease is common in many parts of the developing world, including areas of South America, South Asia, and Africa. Illness severity is inversely proportional to the patient’s ability to produce a cell-mediated response and creates a range from localized (tuberculoid leprosy) to disseminated disease (lepromatous leprosy), with many having borderline cases falling between the two extremes.
Localized disease is limited to one to three skin lesions, typically sharply demarcated, flat, hypopigmented, anesthetic plaques with elevated margins. This is often accompanied by easily discernible peripheral nerve thickening. The most severe forms are characterized by poorly demarcated erythematous macules, papules, or nodules. The peripheral nerves have less palpable findings, but more diffuse nerve involvement is seen in a stocking glove pattern. This results in loss of bone length and insensate extremities, often leading to repetitive trauma, infection, and loss of digits. With diffuse infiltration of the face, the characteristic “leonine facies” is exhibited.
Diagnosis is primarily clinical, along with staining of a slit skin smear or biopsy for acid-fast bacilli. PCR can aid in the diagnosis.
Management and Disposition
There is no specific emergency therapy for leprosy. Patients should be referred to the national treatment program or a clinician experienced with leprosy management. Multidrug therapy is curative using varying combinations of dapsone, rifampin, and clofazimine. The class of disease dictates type and length of treatment. An ophthalmic exam is essential due to a high propensity for corneal abrasions and ulcers.
Leprosy. Typical thickened skin on the external ear of a 31-year-old male with lepromatous leprosy. (Photo contributors: Shannon Langston, MD, and Universidad Peruana Cayetano Heredia, Lima, Peru.)
Leprosy acquired in the southern United States is highly associated with armadillo handling.
The presence of an anesthetic skin lesion should suggest the diagnosis of leprosy.
Multidrug therapy has been made available by WHO free of charge to all patients worldwide and provides a highly effective cure for all types.
The simpler WHO classification categorizes leprosy into localized (paucibacillary) or disseminated (multibacillary) disease.
Leprosy Skin Lesions. Anesthetic skin lesions in a Peruvian patient with borderline leprosy. Borderline disease is not as localized as tuberculoid leprosy and not as widespread as lepromatous disease. (Photo contributors: Rob Greidanus, MD, and Universidad Peruana Cayetano Heredia, Lima, Peru.)
Leprosy. Thickened skin due to bacillary infiltration. Later stage may require digit amputation. (Photo contributor: David Effron, MD.)
Leprosy. Chronic foot changes with ulceration and shortening of the toes. ...