Leprosy is a chronic infectious disease caused by the bacterium Mycobacterium leprae, which primarily affects the skin, peripheral nerves, respiratory system, and eyes.
It has a long incubation period, sometimes taking years to manifest symptoms.
Signs and Symptoms
Early Signs:
Skin Lesions: Pale or reddish patches that are numb to touch.
Numbness: Loss of sensation in affected areas.
Muscle Weakness: Often in the hands and feet.
Progressive Symptoms:
Thickened Skin: Nodules and thickened dermal areas.
Eye Problems: Reduced blinking reflex, dryness, potential blindness.
Ulcers: Chronic skin ulcers, especially on the soles of the feet.
Deformities: Claw-like hands or drop foot due to nerve damage.
Loss of Eyebrows and Eyelashes: Common in advanced cases.
Types of Leprosy
Based on the Ridley-Jopling Classification:
1. Tuberculoid Leprosy (TT):
Few skin lesions, high nerve involvement, strong immune response.
2. Borderline Tuberculoid Leprosy (BT):
Intermediate between tuberculoid and borderline lepromatous.
3. Borderline Borderline Leprosy (BB):
Intermediate form with more lesions and moderate immune response.
4. Borderline Lepromatous Leprosy (BL):
Numerous lesions, weaker immune response.
5. Lepromatous Leprosy (LL):
Many skin lesions and nodules, poor immune response, more severe.
Etiology
Causative Agent: Mycobacterium leprae.
Transmission: Likely through prolonged close contact with an untreated person, possibly via respiratory droplets.
Pathogenesis
Entry: M. leprae enters the body, possibly through the skin or respiratory tract.
Spread: Bacteria preferentially infect peripheral nerves, skin, upper respiratory tract, and eyes.
Immune Response: Depending on the host's immune response, the disease can manifest as either paucibacillary (limited) or multibacillary (widespread).
Treatment
1. Multidrug Therapy (MDT):
Paucibacillary Leprosy: Dapsone and rifampicin for six months.
Multibacillary Leprosy: Dapsone, rifampicin, and clofazimine for 12 months.
2. Supportive Care:
Physical Therapy: To prevent deformities and manage neuropathy.
Surgical Interventions: To correct deformities and manage chronic ulcers.
Eye Care: Regular check-ups to prevent blindness.
Prevention:
Early Diagnosis and Treatment: To reduce transmission.
Contact Tracing and Screening: Of household contacts.