LEPROSY

A chronic infectious disease caused by Mycobacterium leprae – an acid-fast bacillus. It mainly affects the skin, peripheral nerves and mucous membranes. It is transmitted from one person to another via the respiratory tract (possibly, very rarely, through broken skin). It is classified into paucibacillary (PB) or Multibacillary (MB) Leprosy.

Clinical features

  • One or more hypopigmented (pale) skin patches with definite loss of sensation
  • There may be skin nodules or smooth, shiny diffuse thickening of the skin without loss of sensation
  • Damage to peripheral nerves: thickened nerve, loss of unction and weakness of muscles supplied by affected nerves

Tuberculoid or Paucibacillary (PB) leprosy

  • 1-5 patches

Lepromatous or Multibacillary (MB) Leprosy

  • More than 5 patches

Differential diagnosis

  • Hypopigmentation e.g. birthmark, early vitiligo
  • Fungal infections of the skin
  • Other nodular conditions, e.g. Kaposi’s sarcoma, neurofibromatosis, secondary syphilis
  • Other causes of peripheral nerve damage, e.g. diabetes mellitus
  • Psoriasis, molluscum contagiosum

Investigations

  • In most cases, a definite diagnosis of leprosy can be made using clinical signs alone
  • At referral centre: stain slit skin smears for Acid Fast Bacilli (AFB)
  • Skin biopsies NOT recommended as a routine procedure

Management

Multi-drug therapy (MDT) for leprosy is presented in the form of various monthly dose blister packs for PB leprosy and MB leprosy, with special packs for children.
Paucibacillary leprosy (Treat for 6 months)

  • The standard adult PB treatment regimen is:
    • Rifampicin 600 mg once a month
    • Dapsone 100 mg tab once daily
  • The standard child (10-14 years) PB treatment regimen is:
    • Rifampicin 450 mg once a month
    • Dapsone 50 mg once daily

Multibacillary leprosy (Treat for 12 months)

  • The standard adult MB treatment regimen is:
    • Rifampicin 600 mg once a month
    • Clofazimine 300 mg once a month and 50 mg daily
    • Dapsone 100 mg once daily
  • The standard child (10-14 years) PB treatment regimen is:
    • Rifampicin 450 mg once monthly
    • Clofazimine 150 mg once a month and 50 mg every other day
    • Dapsone 50 mg daily
  • Ensure that patients take their medicines regularly and complete the dose

MDT for children <10 years of age

  • Appropriate dose is determined based on body weight
    • Rifampicin 10 mg/kg once monthly
    • Clofazimine 6 mg/kg once a month and 1 mg/kg daily
    • Dapsone 2 mg/kg daily
  • The standard child blister pack may be broken up so that the appropriate dose is given

Steroids for treatment of severe leprae reactions

  • Prednisolone 40 mg once daily in morning
    • Treat for 12 weeks in PB and 24 weeks in MB
    • Reduce dose gradually by 10–5 mg once every 2 weeks (PB) or 3 weeks (MB)

Note

  • In patients co-infected with HIV, do not use dapsone. In PB leprosy, substitute dapsone with clofazimine in appropriate doses
  • Health worker should directly observe that the medicines taken once a month are actually swallowed
  • Treatment durations longer than 12 months and steroids for leprae reactions should only be prescribed by specialists at referral centres
  • Lepra reactions: sudden inflammation (pain, redness, swelling, new lesions, loss of nerve function) in skin lesions or nerves of a person with leprosy. They can occur before, during or after MDT completion.
  • Severe leprae reaction (Type 2) are also known as Erythema Nodosum Leprosum (ENL or Type 2 reactions)
  • All patients should undergo rehabilitation and physiotherapy. Counsel patient on: need to complete treatment, presence of residual signs after completion of treatment
  • Presence of residual signs or post-treatment reactions is NOT an indication to re-start the treatment
  • Refer to the National Tuberculosis and Leprosy Programme (NTLP) manual 2016 for more details

Prevention

  • Early diagnosis of cases and effective treatment
  • Screening of contacts of known patients
  • BCG vaccination may be helpful