Leprosy: Causes, Symptoms and Treatment

Table of Contents

What is Leprosy?

Leprosy, also known as Hansen’s disease, is a chronic infectious disease and a Neglected Tropical Disease (NTD) caused by a bacterium called Mycobacterium leprae.
Leprosy primarily affects the skin, peripheral nerves, upper respiratory tract mucosa, and the eyes.
Although Leprosy is chronic infectious disease, it is curable and early treatment prevents disability.

What are the Myths and Facts About Leprosy?

Myths about Leprosy

Leprosy is hereditary.
Leprosy is a curse or punishment.
Leprosy has no cure.
Leprosy causes body parts to fall off.

Fact about Leprosy

Leprosy has nothing to do with genetics; it can only be caused by the Mycobacterium leprae bacterium.
Leprosy is a bacterial disease caused by Mycobacterium leprae, not related to sins or curses.
It is a bacterial disease and is fully curable with multidrug therapy.
Untreated leprosy can damage nerves, leading to injuries, but body parts do not fall off.

S.N	Myths	Facts
1.	Leprosy is hereditary.	Leprosy has nothing to do with genetics; it can only be caused by the Mycobacterium leprae bacterium.
2.	Leprosy is a curse or punishment.	Leprosy is a bacterial disease caused by Mycobacterium leprae, not related to sins or curses.
3.	Leprosy has no cure.	It is a bacterial disease and is fully curable with multidrug therapy.
4.	Leprosy causes body parts to fall off.	Untreated leprosy can damage nerves, leading to injuries, but body parts do not fall off.

What Causes Leprosy?

Mycobacterium leprae and Mycobacterium lepromatosis, acid-fast rod-shaped bacilli causes leprosy.

How Does Leprosy Transmit/Spread (Is Leprosy Contagious?)

Leprosy is contagious but not highly infectious and does not spread through casual contact or shared objects.
It is mainly transmitted through respiratory droplets or nasal secretions during prolonged, close contact with an untreated person.

What are the Risk Factors for Leprosy Infection?

Prolonged contact with untreated leprosy patients
Weak immunity
Genetic factors
Poor living conditions
Endemic areas
Occupational exposure
Delayed treatment
Higher occurrence in adults

What are the Different Types of Leprosy?

Generally, leprosy is classified into two types; Paucibacillary leprosy and multibacillary leprosy.

Paucibacillary leprosy

Paucibacillary leprosy is a less severe variant with less than five skin lesions.
It has low bacterial load and affects skin for few years
Paucibacillary leprosy results in negative bacterial testing
Paucibacillary leprosy does not affect the nerve.
It has mild symptoms, lower transmission risk and treatment duration is also relatively shorter.

Multibacillary leprosy

Multibacillary leprosy is a more severe and broad infection with more than five skin lesions.
It has high bacterial load and affects skin and other body parts for longer period of time.
Multibacillary leprosy results in positive bacterial testing.
It affects the nerve and its symptoms are more severe.
The transmission risk and treatment duration of multibacillary leprosy is higher.

Aspect	Paucibacillary Leprosy	Multibacillary Leprosy
Definition	A type of leprosy characterized by a low bacterial load	A form of leprosy characterized by a high bacterial load
Bacterial load	Relatively Low	Much higher as compared to paucibacillary leprosy
Number of Skin lesions	Few skin lesions	Numerous skin lesions. Most of them are poorly defined
Skin involvement	Affects skin of few areas	Extensive involvement over various body parts
Nerve involvement	Minimal or absent	Often present and pronounced
Severity of symptoms	Mild	Moderate to More severe symptoms
Transmission risk	Lower	Higher
Treatment duration	Shorter duration of treatment	Longer duration of treatment
Antibiotics regimen for Treatment	Usually requires fewer drugs	Requires a combination of multiple antibiotics to fully cure
Relapse rate	Lower rate of relapse	Higher rate of relapse
Diagnosis	Often easier to diagnose	Sometimes, it becomes more challenging to diagnose

Ridley–Jopling Classification of Leprosy

Based on signs and symptoms and histopathological findings, the Ridley-Jopling system classifies leprosy from a spectrum of high cell-mediated immunity to low cell-mediated immunity:

Tuberculoid leprosy: Few skin lesions, strong immunity, low bacteria
Borderline Tuberculoid (BT) leprosy: More lesions than TT, fairly good immunity
Mid-borderline (BB) leprosy: Many mixed-type lesions, unstable immunity
Borderline Lepromatous (BL) leprosy: Numerous lesions, weak immunity, high bacteria
Lepromatous (LL) leprosy: Widespread lesions, very weak immunity, highest bacterial load

What are the Signs & Symptoms of Leprosy?

Skin lesions

Early signs include skin lesions.

Discoloured or lighter patches of skin
Firm, rounded bumps under the skin
Thick, stiff, or dry skin
Painless ulcers on the soles of the feet
Painless swellings or lumps may appear on the face or earlobes.
Loss of eyebrows or eyelashes

Nerve damage

Numbness of the skin in affected areas
Muscle weakness or paralysis can occur, especially in the hands and feet.
Peripheral nerves may become enlarged, commonly around the elbows, knees, and neck.

Eye Problems

Eye Pain
Dry Eye
Difficulty in blinking
Vision loss

What are the Complications and Disability caused due to Leprosy?

Leprosy affects the skin and peripheral nerves. If not diagnosed and treated early, it can cause permanent disabilities and deformities.

Nerve damage causing loss of pain and sensation
Muscle weakness leading to claw hand and foot drop
Facial disfigurement with swelling, bumps, and nodules
Eye complications:
Inability to close eyelids (lagophthalmos)
Dry eyes and keratitis
Iridocyclitis
Cataract
Blindness or glaucoma
Nasal damage: Chronic nasal congestion and nosebleeds
Hair loss
Kidney failure
Reproductive complications, including erectile dysfunction and infertility in men

How Is Leprosy Diagnosed?

Clinical Examination

Leprosy is primarily diagnosed clinically, though laboratory tests may be used in difficult cases.
The disease usually presents with skin lesions and peripheral nerve involvement.
Diagnosis is confirmed if at least one of the following cardinal signs is present:
Reduced or absent sensation in light or reddish skin patches
Enlarged nerves with sensory loss and/or muscle weakness
Detection of Mycobacterium leprae in a slit-skin smear

What are the Laboratory Tests Related to Leprosy?

Slit Skin Smear

A slit skin smear is taken from skin lesions as well as from the left forehead and ear lobes.
The smears are stained using the Ziehl–Neelsen (Z-N) method, and microscopic examination was performed to detect Mycobacterium leprae.

Punch skin biopsy

Samples are taken from skin lesions, and biopsy samples are included tissue up to the dermis for histopathological examination in patients with leprosy.

Why is Early Detection Important in Leprosy?

Early detection allows treatment to begin before the development of nerve impairment and physical deformities, thereby preventing irreversible disability.
Early detection of leprosy facilitates cost-effective management, minimizing long-term healthcare expenditures related to disability care, rehabilitation, and social support.

What is the Treatment for Leprosy?

Multidrug Therapy (MDT) for Leprosy

MDT is the WHO-recommended treatment for leprosy.
It combines antibiotics (rifampicin, dapsone, clofazimine) to kill the bacteria and prevent resistance.
MDT is safe, effective, and free in endemic countries.
Treatment duration:
PB leprosy: 6 months
MB leprosy: 12 months
MDT quickly stops transmission and prevents nerve damage.
Completing treatment results in cure.

Managing Leprosy Reactions (Type 1 and Type 2)

Type 1 Lepra Reaction (Reversal Reaction)

Mild type 1 lepra reactions are managed with supportive care, including topical steroids and painkillers, along with regular monitoring to detect early nerve involvement.
Severe type 1 reactions with nerve impairment require prompt treatment using prednisone or prednisolone at 0.5–1 mg/kg/day, followed by a slow taper once inflammation subsides.
Ciclosporin may be used as second-line therapy when corticosteroids are ineffective, and nerve decompression surgery may be required if nerve damage persists.
Multidrug therapy with rifampicin, dapsone, and clofazimine should be continued during the reaction.

Type 2 Lepra Reaction (Erythema Nodosum Leprosum)

Mild type 2 lepra reactions presenting with skin lesions only can be managed with supportive care, including painkillers, fever control, and close clinical monitoring.
Severe type 2 reactions require systemic treatment with prednisone at about 1 mg/kg/day, which should be tapered rapidly after clinical improvement.
Clofazimine is useful in preventing recurrent ENL, and thalidomide at 400 mg/day may be used initially and tapered over one to two months in severe cases.
In resistant cases, other immunosuppressive drugs such as ciclosporin, azathioprine, methotrexate, mycophenolate mofetil, and pentoxifylline may be considered.

What are the Prevention & Control Mechanisms for Leprosy?

Can Leprosy Be Prevented?

Leprosy can be prevented through early detection and complete treatment of cases with multidrug therapy, which stops transmission and reduces community spread.
Contact screening and regular examination of household and close contacts help identify cases early and prevent further transmission.
Single-dose rifampicin (SDR) chemoprophylaxis for eligible close contacts significantly reduces the risk of developing leprosy.

Role of Contact Tracing and Chemoprophylaxis

Contact Tracing: Identifying and examining household and close contacts of leprosy patients helps detect new cases early and prevents further spread.
Chemoprophylaxis: Giving a single-dose rifampicin (SDR) to eligible contacts reduces their risk of developing leprosy.

What are the Leprosy Elimination Programs and WHO Strategies?

WHO leads global leprosy elimination and supports endemic countries.
Free multidrug therapy (MDT) is provided worldwide by WHO.
The WHO Leprosy Strategy 2021–2030 is titled “Towards Zero Leprosy. It supports achievement of the Sustainable Development Goals.
The strategy focuses on four areas:

1. Implement integrated, country-owned zero leprosy road maps in all endemic countries
2. Scale up leprosy prevention alongside integrated active case detection
3. Manage leprosy and its complications and prevent new disability, and
4. Combat stigma and ensure human rights are respected. Interruption of transmission and elimination of disease are at the core of the Strategy.

Social & Public Health Aspects

What are the Social Stigmas related to Leprosy?

People with leprosy often face discrimination and exclusion.
Stigma can lead to delayed diagnosis and treatment, increasing disability risk.
Psychological impacts include depression, anxiety, social isolation, and low self-esteem.

Disability, Rehabilitation, and Inclusion

Effective management of leprosy complications, including reactions and neuritis, can prevent or minimise the development of further disabilities.
Physiotherapy, occupational therapy, patient education, and counselling for physical rehabilitation.
Employment opportunities, stigma reduction, and community support helps affected individuals live normal lives.

Frequently Asked Questions (FAQs)

Is Leprosy Curable?

Yes, leprosy is completely curable with multidrug therapy (MDT).
Treatment duration depends on type: 6 months for paucibacillary and 12 months for multibacillary cases.

Can Leprosy Come Back After Treatment?

Yes, leprosy can rarely recur after treatment.
Stopping antibiotics early may allow the bacteria to grow again, causing relapse.
Continuous exposure to Mycobacterium leprae after cure can also increase the risk.
Completing the full course of multidrug therapy (MDT) and avoiding prolonged exposure reduces the chance of recurrence.

Does Leprosy Cause Permanent Disability?

Leprosy itself does not directly cause disability, but delayed diagnosis and untreated nerve damage can lead to permanent impairments. Early detection and timely MDT can prevent most disabilities.