Hansen Disease (Leprosy) in Children
Introduction to Hansen's Disease (Leprosy) in Children
Hansen's Disease, commonly known as leprosy, is a chronic infectious disease caused by Mycobacterium leprae. It primarily affects the skin, peripheral nerves, upper respiratory tract, and eyes.
Key points:
- Caused by Mycobacterium leprae, an acid-fast bacillus
- Long incubation period, ranging from 2 to 20 years
- Can affect individuals of all ages, including children
- Early diagnosis and treatment are crucial to prevent disabilities
- Stigma associated with the disease remains a significant challenge
Epidemiology of Hansen's Disease in Children
While leprosy can affect people of all ages, its occurrence in children is an important indicator of ongoing transmission in the community.
Key epidemiological features:
- Global prevalence has significantly decreased due to multi-drug therapy (MDT)
- Children under 15 years account for about 7-10% of new cases globally
- Higher incidence in certain countries: India, Brazil, Indonesia, among others
- Household contacts of leprosy patients are at higher risk
- Boys are more commonly affected than girls in most endemic areas
According to WHO data:
- In 2019, children accounted for 7.4% of new leprosy cases globally
- The proportion of child cases varies significantly between regions
Pathophysiology of Hansen's Disease in Children
The pathophysiology of leprosy in children is similar to adults but with some unique features due to their developing immune system.
Key aspects of pathophysiology:
- M. leprae primarily infects Schwann cells of peripheral nerves and skin macrophages
- The clinical manifestations depend on the host's immune response to the bacterium
- Two main forms: paucibacillary (PB) and multibacillary (MB)
- Children more commonly present with paucibacillary forms
- Nerve damage can occur even before clinical signs appear
Immunological factors:
- Cell-mediated immunity plays a crucial role in the disease spectrum
- Children may show a more dynamic immunological response
- Reactions (Type 1 and Type 2) can occur, but are less common in children
Clinical Presentation of Hansen's Disease in Children
The clinical presentation of leprosy in children can be subtle and easily missed, making early diagnosis challenging.
Common presentations:
- Single or multiple hypopigmented or erythematous skin patches
- Decreased or absent sensation in affected skin areas
- Enlargement of peripheral nerves
- Numbness or weakness in hands or feet
Classification:
- Paucibacillary (PB): 1-5 skin lesions, no bacteria on skin smear
- Multibacillary (MB): More than 5 skin lesions, positive skin smear
Ridley-Jopling classification (less commonly used in children):
- Tuberculoid (TT)
- Borderline Tuberculoid (BT)
- Borderline Borderline (BB)
- Borderline Lepromatous (BL)
- Lepromatous (LL)
Leprosy reactions:
- Type 1 (Reversal) Reaction: Acute inflammation in skin lesions and nerves
- Type 2 Reaction (Erythema Nodosum Leprosum): Systemic inflammatory response, less common in children
Diagnosis of Hansen's Disease in Children
Diagnosis of leprosy in children requires a high index of suspicion and a combination of clinical, bacteriological, and sometimes histopathological examination.
Diagnostic approach:
- Detailed history, including contact with leprosy patients
- Thorough physical examination, especially of the skin and peripheral nerves
- Sensory testing of skin lesions (may be challenging in young children)
- Slit-skin smear examination for acid-fast bacilli
- Skin biopsy for histopathological examination (when available)
Cardinal signs (at least one must be present):
- Definite loss of sensation in a pale (hypopigmented) or reddish skin patch
- Thickened or enlarged peripheral nerve with loss of sensation and/or weakness of muscles supplied by that nerve
- Presence of acid-fast bacilli in a slit-skin smear
Additional tests:
- PCR-based tests: Can detect M. leprae DNA, useful in difficult-to-diagnose cases
- Serology: Anti-PGL-I antibody test (limited utility in PB cases)
- Nerve conduction studies: To assess nerve function impairment
Treatment of Hansen's Disease in Children
Treatment of leprosy in children follows the same principles as in adults, with some adjustments for weight-based dosing.
General principles:
- Multi-drug therapy (MDT) is the standard treatment
- Duration depends on the classification (PB or MB)
- Regular follow-up to monitor treatment response and complications
- Management of reactions and prevention of disabilities
WHO-recommended MDT regimens:
1. Paucibacillary (PB) leprosy:
- Duration: 6 months
- Rifampicin: Once a month
- Dapsone: Daily
2. Multibacillary (MB) leprosy:
- Duration: 12 months
- Rifampicin: Once a month
- Clofazimine: Daily and a larger dose once a month
- Dapsone: Daily
Management of reactions:
- Type 1 reactions: Corticosteroids (prednisolone)
- Type 2 reactions: Corticosteroids, thalidomide (in post-pubertal males)
Supportive care:
- Wound care for ulcers
- Physiotherapy and occupational therapy for prevention of disabilities
- Psychosocial support for the child and family
Prevention and Control of Hansen's Disease in Children
Prevention and control strategies are crucial to reduce the burden of leprosy in children and communities.
Key prevention strategies:
- Early case detection and treatment
- Contact tracing and post-exposure prophylaxis
- BCG vaccination (offers some protection against leprosy)
- Health education and awareness programs
Contact management:
- Screening of household contacts, especially children
- Single dose rifampicin as post-exposure prophylaxis for contacts
- Regular follow-up of contacts for early signs of leprosy
Community-based interventions:
- Active case-finding in endemic areas
- School-based screening programs
- Integration of leprosy services with general health services
Addressing stigma:
- Community education to reduce stigma and discrimination
- Psychosocial support for affected children and families
- Advocacy for the rights of people affected by leprosy
Hansen Disease (Leprosy) in Children
- What is the causative agent of Hansen disease (leprosy)?
Mycobacterium leprae - What is the primary mode of transmission for leprosy?
Prolonged close contact with untreated infected individuals, mainly through respiratory droplets - What is the average incubation period for leprosy?
3-5 years, but can range from 6 months to 20 years or more - Which age group of children is most commonly affected by leprosy?
Children between 10-14 years old - What are the two main types of leprosy based on the immune response?
Paucibacillary (PB) and Multibacillary (MB) le - What is the characteristic skin lesion in paucibacillary leprosy?
Hypopigmented, well-defined patches with decreased sensation - What is the main clinical feature of multibacillary leprosy?
Multiple, symmetrically distributed skin lesions with nerve involvement - Which nerve is most commonly affected in leprosy?
Ulnar nerve - What is a common early sign of leprosy in children?
Single, hypopigmented patch on the face or extremities - What test is used to assess sensory loss in suspected leprosy lesions?
Monofilament test or cotton wool test - What is the gold standard diagnostic test for leprosy?
Skin smear microscopy for acid-fast bacilli - What is the recommended treatment regimen for paucibacillary leprosy in children?
Rifampicin and Dapsone for 6 months - What is the recommended treatment regimen for multibacillary leprosy in children?
Rifampicin, Dapsone, and Clofazimine for 12 months - What is a leprosy reaction?
An acute inflammatory response that can occur before, during, or after treatment - What are the two main types of leprosy reactions?
Type 1 (reversal) reaction and Type 2 (erythema nodosum leprosum) reaction - What is the primary treatment for severe leprosy reactions?
Corticosteroids - What is lagophthalmos in leprosy?
Inability to close the eye completely due to facial nerve damage - What is the most common deformity in untreated leprosy?
Claw hand - What is the role of BCG vaccination in leprosy prevention?
It offers some protection against leprosy, with efficacy varying from 20-80% - How long should household contacts of a leprosy patient be monitored?
At least 5 years after the index case completes treatment - What is the global strategy for leprosy according to WHO?
Zero disability in children with leprosy by 2020 and beyond - What is silent neuropathy in leprosy?
Nerve function impairment without signs of inflammation or pain - What is the Ridley-Jopling classification system used for in leprosy?
To classify leprosy based on clinical, histopathological, and immunological features - What is indeterminate leprosy?
An early, unstable form of leprosy that can progress to other forms or self-heal - What is the importance of examining the earlobes in suspected leprosy cases?
Mycobacterium leprae prefers cooler body areas, and earlobes are a common site for early detection - What is the role of lepromin test in leprosy?
It assesses the cell-mediated immune response to M. leprae antigens, helping in classification - What is the recommended duration for follow-up after completing leprosy treatment?
At least 2 years for paucibacillary and 5 years for multibacillary leprosy - What is the risk of relapse in properly treated pediatric leprosy cases?
Generally low, less than 1% per year - What is the role of molecular techniques like PCR in leprosy diagnosis?
They can detect M. leprae DNA in difficult-to-diagnose cases or for monitoring treatment response - What is the significance of "grade 2 disability" in leprosy?
It indicates visible deformities or damage and is a key indicator for late diagnosis
