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Infectious Diseases

Leprosy

A chronic infectious disease caused by Mycobacterium leprae, primarily affecting the skin, peripheral nerves, and mucous membranes. Classified as Paucibacillary (PB) or Multibacillary (MB).

Also known as: Hansen's Disease

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Referral and warning signs

When to refer

Refer suspected cases to designated Leprosy treatment centres (often integrated with TB services - NTLP) for confirmation and initiation of MDT. Refer patients with: Severe Lepra reactions, Nerve damage requiring specialist management (splinting, surgery), Eye complications, Severe disability needing rehabilitation/surgery.

Red flags

  • Sudden onset of nerve pain, tenderness, or loss of function (suggests Type 1 reaction/neuritis).
  • Painful red eye or reduced vision.
  • Signs of severe Type 2 reaction (high fever, widespread painful nodules).
  • Signs of secondary infection in ulcers.

Signs and symptoms

  • Cardinal Signs (At least one needed for diagnosis):
  • 1. Skin Lesion(s) consistent with leprosy with definite sensory loss.
  • - Lesions are typically hypopigmented (pale) or reddish patches.
  • - Sensory loss (light touch, pain, temperature) within the patch is key.
  • 2. Thickened or enlarged peripheral nerve(s), with associated sensory loss and/or muscle weakness in the area supplied by the nerve.
  • - Common nerves: Ulnar, median, radial, common peroneal, posterior tibial.
  • 3. Presence of Acid-Fast Bacilli (AFB) on slit-skin smear examination (confirmatory, especially for MB).
  • Other Signs:
  • - Numbness or tingling in hands or feet.
  • - Muscle weakness (e.g., foot drop, claw hand).
  • - Painful or tender nerves.
  • - Swelling or lumps (nodules, plaques) on face or earlobes (esp. MB).
  • - Painless wounds, burns, or ulcers on hands or feet (due to sensory loss).
  • - Eye problems (dryness, inability to close eyelids - lagophthalmos, corneal ulcers, blindness).
  • - Nasal stuffiness, epistaxis.

Risk factors

  • Prolonged close contact with untreated MB leprosy patients.
  • Living in endemic areas.
  • Possible genetic susceptibility.
  • Immunodeficiency (though not typically an AIDS-defining illness).

Diagnosis

Clinical assessment

Diagnosis based on finding at least one cardinal sign. Careful examination of skin (lesion morphology, number, sensation testing) and peripheral nerves (palpation for thickening, testing sensation/muscle power) is crucial.

Classification

  • Paucibacillary (PB): 1-5 skin lesions. Slit-skin smears usually negative for AFB.
  • Multibacillary (MB): >5 skin lesions OR Nerve involvement OR Positive slit-skin smears.

Differential diagnosis

  • Fungal skin infections (Tinea corporis/versicolor - check sensation).
  • Vitiligo (complete depigmentation, normal sensation).
  • Pityriasis alba.
  • Other causes of hypopigmented patches.
  • Other causes of peripheral neuropathy (diabetes, nutritional, trauma).
  • Cutaneous leishmaniasis, Sarcoidosis, Lymphoma, Secondary syphilis, Neurofibromatosis (for nodules).

Investigations

  • Thorough clinical skin and neurological examination.
  • Slit-Skin Smears: Taking small scraping from skin lesion edge or earlobe, stained for Acid-Fast Bacilli (AFB - Ziehl-Neelsen). Primarily for confirming MB and monitoring treatment response.
  • Skin Biopsy: For histology if diagnosis uncertain (referral centre).

Diagnostic criteria

Presence of at least one cardinal sign (skin lesion with sensory loss, thickened nerve with deficit, positive skin smear).

Management

Non-pharmacological management

  • Patient education about disease, treatment duration, adherence, prevention of disability.
  • Management of disabilities: Self-care training (soaking/oiling dry skin, wound care for insensitive limbs), Physiotherapy (exercises for muscle weakness), Splinting, Protective footwear (e.g., MCR sandals), Eye care (lubrication, protection).
  • Management of Lepra reactions (see below).
  • Psychosocial support.

Pharmacological treatment

  • Multi-Drug Therapy (MDT): Standardized blister packs provided by NTLP. Treatment differs for PB and MB.
  • Paucibacillary (PB) MDT (6 months):
  • - Rifampicin 600mg ONCE monthly (supervised).
  • - Dapsone 100mg DAILY (self-administered).
  • (Child 10-14y: Rifa 450mg monthly, Dap 50mg daily. Child <10y/<40kg: Rifa 10mg/kg monthly, Dap 2mg/kg daily).
  • Multibacillary (MB) MDT (12 months):
  • - Rifampicin 600mg ONCE monthly (supervised).
  • - Clofazimine 300mg ONCE monthly (supervised) + 50mg DAILY (self-administered).
  • - Dapsone 100mg DAILY (self-administered).
  • (Child 10-14y: Rifa 450mg monthly, Clofa 150mg monthly + 50mg daily, Dap 50mg daily.
  • (Child <10y/<40kg: Rifa 10mg/kg monthly, Clofa 6mg/kg monthly + 1mg/kg daily, Dap 2mg/kg daily).
  • Management of Lepra Reactions (Inflammatory episodes): (LOC: RR / Specialist guidance)
  • - Type 1 Reaction (Reversal Reaction): Inflammation of existing lesions/nerves. Treat with Prednisolone 40mg daily, tapered slowly over 12-24 weeks. Continue MDT.
  • - Type 2 Reaction (Erythema Nodosum Leprosum - ENL): Painful nodules, fever, malaise. Treat with Prednisolone (as above). Clofazimine (part of MB MDT) also helps. Thalidomide used in some centres (teratogenic). Continue MDT.
  • Important Notes:
  • - Monthly doses (Rifampicin, Clofazimine loading dose) should be Directly Observed Therapy (DOT).
  • - Do NOT use Dapsone in HIV+ patients already on Cotrimoxazole prophylaxis (use alternative regimen if needed - specialist consult).
  • - MDT should be completed even if reactions occur.
  • - Residual signs/post-treatment reactions are NOT indication to restart MDT.

Monitoring

Monitor adherence to MDT. Assess for Lepra reactions and nerve damage regularly during and after treatment. Monitor disability status.

Complications

  • Peripheral nerve damage -> Sensory loss, Muscle weakness/paralysis, Deformities (claw hand, foot drop).
  • Lepra reactions (Type 1 and Type 2/ENL).
  • Eye complications (lagophthalmos, corneal ulceration, blindness).
  • Chronic ulcers/wounds on insensitive limbs.
  • Osteomyelitis / Bone resorption.
  • Amyloidosis / Renal impairment (less common).
  • Social stigma and discrimination.

Prevention

  • Early diagnosis and prompt initiation of MDT (reduces transmission).
  • Contact tracing and screening of close contacts.
  • Single Dose Rifampicin (SDR) prophylaxis for eligible contacts (see UCG table).
  • BCG vaccination may offer some cross-protection.
  • Health education to reduce stigma.

Patient education

  • Explanation that leprosy is curable with MDT.
  • Importance of completing the full course of treatment.
  • How to take medications (daily vs monthly supervised).
  • Recognizing signs of Lepra reactions and seeking care promptly.
  • Self-care practices to prevent injuries and disabilities (checking hands/feet, skin care, eye care).
  • Reassurance about low contagiousness after starting MDT.
  • Addressing stigma and psychosocial support.

Uganda-specific notes

Leprosy control managed by the National Tuberculosis and Leprosy Programme (NTLP). MDT is provided free of charge. Focus on early case detection, complete treatment, prevention of disability (POD), and reduction of stigma. SDR prophylaxis for contacts implemented.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 2, Section 2.1.4

  • National Tuberculosis and Leprosy Programme (NTLP) Manual, MOH Uganda, 2016

    (Provides more detailed operational guidance)

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