Clinical Testing and Diagnosis for Hansen's disease (Leprosy)

Key points

  • Hansen’s disease is diagnosed based on clinical presentation and the diagnosis is confirmed by skin or nerve biopsy and acid-fast staining.
  • In the United States, the National Hansen’s Disease Program can provide diagnostic services.
  • Hansen's disease is a reportable condition to state or local health departments.

Arranging diagnostic testing

In the United States, the National Hansen’s Disease Program can provide diagnostic services.

Healthcare providers should seek prompt consultation with National Hansen's Disease Program. Phone 1-800-642-2477, weekdays 9 AM to 5:30 PM ET (in Hawaii: 1-808-733-9831).

Recommended specimens

Depending on the form of Hansen's disease suspected by the treating physician, the following specimens may be collected:

  • Skin smears from the earlobes, elbows, and knees
  • Skin biopsy from edges of active patches
  • Nerve biopsy from thickened nerves

Recommended tests

Biopsies are needed to definitively diagnose and classify Hansen's disease. Slit skin smear may also be helpful in diagnosing those with multibacillary (MB) Hansen's disease.

In MB Hansen's disease, tissue biopsy of various affected sites may reveal typical histopathologic changes and large numbers of foam cells. Foam cells are macrophages that have ingested M. leprae bacteria, but are unable to digest the organisms. The M. leprae bacteria multiply and use the macrophage as a method of transport throughout the body. This is how the bacteria cause the multiple lesions that appear in all parts of the body in MB leprosy patients.

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This photomicrograph reveals some of the classic histopathologic changes found in a skin section from an individual with a case of the leprosy, which may have been the paucibacillary form of the disease, though this has not been confirmed. Shown here is a nerve surrounded by a dense infiltrate consisting of undifferentiated histiocytes and large numbers of lymphocytes. The nerve sheath and endoneural region of the nerve were also infiltrated. This neural involvement was found to be independent of any pathology of the upper corium.
This photomicrograph shows classic histopathologic changes in a skin section from someone with Hansen's disease. A nerve is surrounded by a dense infiltrate of undifferentiated histiocytes and large numbers of lymphocytes. The nerve sheath and endoneural region of the nerve were also infiltrated. This neural involvement was found to be independent of any pathology of the upper corium.
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This photomicrograph reveals some of the histopathologic changes in a specimen of human testicular tissue, which included a large number of “foam cells”. These changes were attributed to a case of multibacillary (MB) leprosy.
This photomicrograph reveals some of the histopathologic changes in a specimen of human testicular tissue, which included a large number of “foam cells”. These changes were attributed to a case of MB leprosy.
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Laboratory workers should use the Ziehl-Neelson method using 5% sulphuric acid as decolorizing agent. The presence of acid-fast bacilli confirms the diagnosis of Hansen's disease.

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This photomicrograph of a skin tissue sample from a patient with Hansen's disease shows a cutaneous nerve, which had been invaded by numerous M. leprae bacteria (shown in red).
A photomicrograph of a skin tissue sample shows a cutaneous nerve, which had been invaded by numerous M. leprae bacteria (shown in red).
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This acid-fast-stained photomicrograph of a tissue sample extracted from a patient with leprosy shows a chronic inflammatory lesion known as a granuloma, within which numerous red-colored M. leprae bacteria are visible.
This acid-fast-stained photomicrograph of a tissue sample shows a granuloma, within which many red-colored M. leprae bacteria are visible.
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Reporting cases

Hansen's disease is a reportable condition in all states and territories. Hansen's disease cases must be reported to jurisdictions when identified by a healthcare provider, hospital, or laboratory. Specific reporting requirements may vary by jurisdiction. Public health authorities should submit a Hansen's Disease Case Report form to CDC.

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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)