Clinical Overview of Hansen's Disease (Leprosy)

Key points

  • Up to 225 cases of Hansen's disease are identified in the U.S. every year.
  • There are three types of Hansen's disease, each with slightly different signs and symptoms.
  • In the U.S., people with the disease may be treated at specialized clinics run by the National Hansen's Disease Program. There are several federally supported outpatient clinics throughout the country.
  • Hansen's disease can be cured with multidrug therapy, which consists of a combination of antibiotics.
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Etiology

Hansen's disease is caused by an acid-fast rod-shaped bacillus Mycobacterium leprae and Mycobacterium lepromatosis. The organism multiplies very slowly (dividing approximately once every 13 days).

It is an obligate intracellular pathogen that lacks several genes needed for independent survival. Thus, it has never been grown in bacteriologic media. However, it has been grown in mouse foot pads.

At-risk populations

Hansen’s disease is very rare in the United States, with around 150 cases reported per year. Most people with Hansen’s disease in the U.S. became infected in a country where it is more common.

However, there have been cases of Hansen's disease reported in U.S. residents with no international travel.

Signs and symptoms

There are three types of Hansen's disease, each with slightly different signs and symptoms. Sometimes, there are other clinical presentations due to the diseases wide range of possible clinical manifestations.

This is the most common form of Hansen's disease. Skin lesions are numerous and may be found anywhere on the body. Peripheral nerves are affected as well, with ensuing weakness and loss of sensation.

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This young woman presented with a case of borderline Hansen’s disease with bilateral involvement of the patient’s buccinator, or cheek muscles, as well as dermatomyositis evidenced by the cutaneous rash-like discoloration overlying the muscles beneath.
A woman with borderline Hansen’s disease involving both cheek muscles and dermatomyositis as seen by the cutaneous rash-like discoloration

PB Hansen's disease is characterized by hypopigmented or hyperpigmented skin macules that exhibit loss of sensation. This is due to infection of the peripheral nerves supplying the region. The body's immune response may also result in swelling of the peripheral nerves. These enlarged nerves may be palpated under the skin and may be tender to the touch.

The nerves most likely to swell are:

  • Great auricular nerve
  • Ulnar nerve above the elbow and dorsal cutaneous branches at the wrist
  • Median nerve at the wrist (in the carpal tunnel)
  • Radial nerve (superficial at wrist)
  • Common peroneal nerve
  • Posterior tibial nerve, posterior to the medial malleolus
  • Sural nerve
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This patient presented to a clinical setting with an active cutaneous lesion on the left hand, which was determined to be due to paucibacillary Hansen’s disease.
This patient presented to a clinical setting with an active cutaneous lesion on the left hand, which was determined to be due to paucibacillary Hansen’s disease.
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This patient presented to a clinical setting with an inflammatory cutaneous lesion on the thorax, which was determined to be the paucibacillary form of Hansen’s disease. Note the enlarged costal nerves below the skin that were affected by the disease and which were supplying the leprous lesion.
This patient presented to a clinical setting with an inflammatory cutaneous lesion on the thorax, which was determined to be PB Hansen’s disease. Note the enlarged costal nerves below the skin which were supplying the leprous lesion.
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A light-colored skin lesion on someone's chest
A large lesion on the man’s left chest is shown here, attributed to paucibacillary (PB) Hansen’s disease.
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Visible enlargement of the great auricular nerve due to infection with M. leprae.
Visible enlargement of the great auricular nerve due to infection with M. leprae.

MB Hansen's disease is characterized by generalized or diffuse involvement of the skin and a thickening of the peripheral nerves. It has the potential to involve other organs, the eyes, nose, testes, and bone. The nodular form of this condition is the most advanced form of the disease. Ulcerated nodules contain large numbers of M. leprae acid-fast bacilli packed in macrophages that appear as large foamy cells.

MB Hansen's disease is associated with:

  • Multiple, symmetrically distributed skin lesions
  • Nodules
  • Plaques
  • Thickened dermis
  • Involvement of the nasal mucosa resulting in congestion and epistaxis
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The face of this male patient exhibited some of the pathologic characteristic associated with a case of nodular lepromatous, or multibacillary (MB), Hansen’s disease. Of note is the presence of cutaneous nodules upon the forehead, nose, cheeks, lips, and chin. The eyebrows are diminished as well.
Characteristics of MB Hansen’s disease: cutaneous nodules on the forehead, nose, cheeks, lips, and chin. Eyebrows are diminished.

Corneal ulcer

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This patient had a corneal ulcer resulting from loss of sensation of the cornea (surface) of the eye and subsequent injury from dust or other particle scratching the surface of the eye without the patient feeling it. Untreated corneal ulcer may result in blindness.
A corneal ulcer due to loss of sensation. Dust scratched the surface of the eye without the patient feeling it. This can cause blindness.

Staphyloma

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This patient presented in a clinical setting with a case of multibacillary leprosy. The photo shows one of the complications of this disease: staphyloma of the left eyeball. A staphyloma involves the protrusion of the wall of the eyeball, exhibiting a dark coloration due to the fact that the inner wall of the globe is pigmented and pushed towards its surface. This degeneration to the globe is a direct result of this illness.
A staphyloma involves the protrusion of the wall of the eyeball, showing a dark coloration. This is a direct result of MB Hansen's disease.

Nose skin changes

From a left lateral perspective, the nose of this patient exhibited cutaneous changes that after a complete differential diagnostic study proved to be multibacillary leprosy. The skin surface had been transformed into reddish-brown nodules atop the left ala, and it appears that the disease process included the left nare and nasal vestibule. Ruled out in the diagnosis was scleroma, syphilis, and malignancy in general.
Due to MB Hansen's disease, the skin had been transformed into reddish-brown nodules atop the left ala, left nare, and nasal vestibule.

Ear lesion

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This patient presented to a clinical setting with an inflammatory lesion on the outer left ear, or pinna, which having undergone a differential diagnosis, was determined to be the paucibacillary form of Hansen’s disease. Eliminated as possible pathologic processes were lupus vulgaris and eczematous dermatitis.
This ear leasion was caused by PB Hansen’s disease.

Testing and diagnosis

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

Treatment and recovery

Hansen's disease is treated with multidrug therapy using a combination of antibiotics depending on the form of the disease:

  • PB Hansen's disease:
    • Daily dapsone and rifampicin once per month
  • MB Hansen's disease:
    • Daily clofazimine is added to rifampicin and dapsone.

Once treatment begins, the patient is no longer considered infectious. Treatment usually lasts one to two years. Hansen's disease can be cured if treatment is completed as prescribed.

Spotlight‎

In the U.S., people with the disease may be treated at specialized clinics run by the National Hansen's Disease Program. There are several federally supported outpatient clinics throughout the U.S. and Puerto Rico.

World Health Organization (WHO) published a detailed guide to classification and treatment of leprosy.

At least one in four patients with Hansen's disease experience reactions during treatment. Reactions may occur before treatment begins or after it is completed. Reactions are not due to medications used to treat the disease, although people treated with clofazimine tend to have slightly fewer episodes.

There are two main groups of reactions:

  1. Type 1 reactions, also called reversal reactions, are typical in PB and borderline Hansen's disease. They show up as edema and erythema of pre-existing lesions. In some cases, neuritis and, rarely, new lesions or fever may occur.
  2. Type 2 reactions, or Erythema nodosum leprosum (ENL), are most frequently seen in patients with MB Hansen's disease. Patients usually present with painful erythematous nodules, often distributed between existing lesions, and moderate to high fever. Inflammation of other tissues may be present, including peripheral neuritis, orchitis, lymphadenitis, iridocyclitis, nephritis, periostitis and arthralgias.

Lucio's phenomenon is a rare reaction of hard-to-heal ulcers, typically seen in patients of Mexican ancestry with MB Hansen's disease.

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The photo shows the left thigh of a patient who had presented to a clinical setting with a case of multibacillary leprosy. One of its symptoms exhibited here is known as erythema nodosum leprosum (ENL). Note the numerous red-purple papules, nodules and plaques that comprise these lesions. A possible cause for this pathologic manifestation is the overabundance of antibody production leading to the deposition of immune complexes in the affected tissues, which triggers this immunologically-based inflammatory response. Usually these maculopapular plaques crop up between already-existing lepromatous lesions.
Type 2 Reaction: A patient with MB Hansen's disease with ENL. Note the numerous red-purple papules, nodules and plaques.

Long-term effects

Over time, if Hansen's disease is not treated, the following complications can occur:

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The face of this female patient exhibited some of the complications associated with multibacillary leprosy. Of note was the depressed nasal bridge known as saddle-nose deformity due to the disintegration of the nasal cartilage in this area. Also note the lack of eyebrows and the mottled coloration of the sclerae bilaterally.
The saddle-nose deformity in this patient with MB Hansen's disease is caused by the disintegration of the nasal cartilage.

This image depicts the dorsal surface of the hands of a patient with a case of nodular multibacillary leprosy. The digits of both hands had been eroded over the course of the illness, and the skin exhibited numerous cutaneous nodules, which were indicative of late-stage disease.
The digits on this person with late-stage MB Hansen's disease had been eroded and the skin exhibited numerous cutaneous nodules.

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This image depicts the ventral surface of the right hand of a patient with a case of multibacillary leprosy. At this late stage, the digits have been almost fully resorbed, except for the index finger, and the proximal remnant of the thumb. There is also a granulomatous inflammatory lesion located on the palmar surface.
The digits of this person with MB Hansen's disease were almost fully resorbed, except for the index finger and the remnant of the thumb.
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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)