Leprosy is a chronic infectious disease of man which predominantly affects peripheral nerves and the skin, although other tissues, such as the eye, mucosa of the upper respiratory tract, muscles, bone and testis can also be involved. It is caused by Mycobacterium leprae. Infection with M. leprae is considered to occur through the nasal mucosa from droplet infection. The earliest clinically detectable lesion is usually the skin and invasion of other organs takes place in lepromatous leprosy (mainly, affecting the eye, testis and muscle). The bacilli multiply inside macrophages - in the histocytes (skin) and Schwann cells (nerves).

The Cardinal Signs of Leprosy are:

• Anaesthesia of the individual skin lesions or in the distribution of peripheral nerves

• Thickened nerves, at the sites of predilection

• Skin lesions, macular or infiltrated hypopigmentation in Blacks or copper coloured (or red) macules in the fairer coloured races

• Presence of the acid-fast bacilli Mycobacterium leprae -in skin smears in lepromatous and border line lesions.

The presence of at least one of the cardinal signs enumerated above suggests a diagnosis of leprosy. The presence of at least two of the first three cardinal signs enumerated indicates a definite diagnosis. Confirmation is, however, by the fourth criteria.

Treatment:

Multibacillary leprosy: Use the following three drugs as follows for a period of one year

Rifampicin, 600 mg p.o. once-monthly, supervised.

S/E: hepatotoxicity, GI disturbances

C/I: hepatic dysfuncion, known hypersensitivity to rifampicin

Dosage forms: capsule, 150 mg, 300 mg, and 600 mg.

OR

Dapsone, 100 mg daily, self-administered.

S/E: Hypersensitivity reactions, hemolytic anemia may occur in individual with G6PD- deficiency. May also cause bone marrow depression and monitoring of the CBC is required; nephrotoxicity

C/I: Hypersensitivity reactions to sulphonamides

Dosage forms: Tablet, 25 mg, 50 mg, 100 mg; Injection, 20 % in 50 ml ampoule

OR

Clofazimine, 300 mg once-monthly, supervised and 50mg daily, self-administered..

S/E: nausea, vomiting, abdominal pain, rash, pruritis, elevation of blood sugar, reddish discoloration of body fluids; photosensitivity; hepatic and renal impairment.

Dosage forms: tablet, 100 mg.

Paucibacillary leprosy: use two drugs as below for a minimum of 6 months.

Rifampicin, 600 mg once-monthly, supervised

(For S/E, C/I and dosage forms, see page 32)

OR

Dapsone 100 mg daily, self-administered

(For S/E, C/I and dosage forms, see page 32)

Treatment of reaction

Mild reactions consisting of type 1 reactions in the absence of pain and tenderness in nerves or type 2 reactions confined to minor skin lesions with little systemic disturbances are treated as follows:

Aspirin, 600 mg to 1200 mg is given 4 hourly, 4 to 6 times daily until the reaction is controlled and then the dose decreased gradually.

S/E: GI irritation; skin reaction; broncho-spasm.

C/E: GI ulceration; hemophilia; children under the age of 12.

Dosage forms: Tablet, 75 mg, 100mg (soluble), 300mg, 500mg (enteric coated), 324 (microfined)

OR

Chloroquine, 150 mg chloroquine base is given upto 3 times daily.

(For S/E, C/I, D/I and dosage forms, see page 15)

Moreover it is often helpful in weaning patients of corticosteroids.

Severe reactions may be considered when there is:

1. Risk of paralysis or anaesthesia in a patient who has neuritis,
2. Danger of skin ulcerations,
3. Risk of development of iridocyclitis or orchitis.

Management of sever reaction: refer to the nearby district hospital