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Leprosy {Hensen’s disease} is caused by

Dr. Chandra Bhan

� Leprosy {Hensen’s disease} is caused by Mycobacterium leprae.

� It has been considered incurable since ages & bears a social stigma.

� Now it is curable, due to development of effective anti-leprotic drugs.

� Though certain forms of leprosy produce oral lesions.

� Sulfones : Dapsone {DDS}� Antitubercular drugs : Rifampicin, ethionamide� Phenazine dye : Clofazimine� Other agents : Ofloxacin, pefloxacin, moxifloxacin,

clarithromycin, minocycline

� It is diamino diphenyl sulfone {DDS}.� It is the oldest, most effective & cheapest – so most

commonly used for leprosy. � It inhibits conversion of PABA to folic acidinhibits conversion of PABA to folic acid ; leprostatic

action.� Its action is also antagonized by PABA.� It is completely and rapidly absorbed orally with long

half-time {about 24 hr}; thus used once a day. It is widely distributed in all the tissues. It is metabolized by acetylation & excreted in urine.

Adverse effects Adverse effects �� HaemolyticHaemolytic anaemiaanaemia {commonest}� Anorexia, nausea & vomiting � Methaemoglobinaemia, headache, nervousness,

insomnia, blurring of vision, peripheral neuropathy-occasional.

� Skin rashes, pigmentation, phototoxicity, fixed drug eruption may occur.

Sulfoxone sodium may be used as an alternative to dapsone if patient is not able to tolerate the drug due to gastric side effects.

� It is fastest acting fastest acting anti-leprotic drug.� It exerts bactericidal effect against M.leprae & most

effective but never used alone as resistance may develop.

� It is effective, if given only once a month because, the development of resistance to rifampicin is very slow, if develops.

� In resistant cases, it is used once a day.

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It is a phenazine dye. Ofloxacin and pefloxacin are highly effective.� It is a phenazine dye. � It binds with mycobacterial DNA & possibly acts by acts by

disruption of membrane and inhibition of potassium disruption of membrane and inhibition of potassium transport. transport.

� It is lepro-static.� It has anti-inflammatory property, thus useful to prevent

erythema nodosum leprosum {lepra infection}.� Its half time is about 70 days. � It can be used as alternative in MDR-TB & MDR-MAC

regimen.

� Ofloxacin and pefloxacin are highly effective.� Ofloxacin was most commonly used in cases where

rifampicin can not be used such as chronic hepatitis. � Moxifloxacin has strong bactericidal action against

M.leprae & most effective FQ against M.tuberculosis as well as M.leprae.

�� ClarithromycinClarithromycin : It is the only macrolide effective in lepromatous leprosy & used in resistant cases in combination with first line drugs.

�� MinocyclineMinocycline : It is highly effective against M.leprae{rifampicin>minocycline>clarithromycin}.

�� RifapentineRifapentine is another promising antileprotic drug; was found to be more potent bactericidal against M.lepraethan rifampicin.

�� PaucibacillaryPaucibacillary leprosy/ leprosy/ tuberculoidtuberculoid {PBL} {PBL} : When small numbers of bacteria are involved in the lesions {1-5}; usually non-infectious type. The lesions are anaesthetic & mycobacteria are rarely present unless in very active stage. Nerve is not involved or single nerve affected. Skin smear is negative at all sites.

�� MultibacillaryMultibacillary leprosy {MBL} leprosy {MBL} : When large no.ofbacterial population is involved in the lesion (>6) infection. It is highly infectious. Skin smear is positive at any one site.

� The multidrug therapy is recommended to reduce/ prevent development of resistance, to reduce duration of treatment, to provide adequate t/t in the primary dapsoneresistant cases, for adequate healing of lesions & ulcers.

LepraLepra reaction typereaction type--1{Reversal reactions} 1{Reversal reactions} : Reversal reaction occurs in leprosy due to delayed hyper-sensitivity to antigen of M.leprae. � Menifestations : Cutaneous ulceration & peripheral

nerve function deficit.� Mild cases can be treated with NSAIDs like paracetamol,

aspirin.� Early t/t is given with corticosteroids {prednisolone} and

clofazimine {less effective}.

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� This is called lepra reaction, is possibly Arthus type of It is the reaction that may occur within 1-2 months of

� This is called lepra reaction, is possibly Arthus type of reaction (type-III hypersensitivity reaction) that occurs in pt. of lepromatous leprosy.

� It is characterized by appearance of raised intra-cutaneous nodules which are tender together with symptoms like malaise & high fever.

� Mild cases can be treated with NSAIDs like paracetamol, aspirin.

� This reaction is treated by clofazimine or corticosteroids. � Thalidomide & chloroquine are also effective for type-II

reaction. � Thalidomide is absolute C/I in pregnancy as it is highly

teratogenic.

� It is the reaction that may occur within 1-2 months of starting the t/t with dapsone in patients of multi-bacillary leprosy. Treatment is similar to lepra reaction.

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