Information About Lepromin Skin Test

Submitted on March 27, 2012

The lepromin skin test is done in order to find out the type of leprosy that a patient has.

What Is Leprosy?

Leprosy is a contagious disease whose history dates back to biblical times. It is also known as Hansen's disease.

Its main features are skin sores which cause severe disfigurement. This is also accompanied by peripheral nerve damage (damage of the nerves in the legs and arms), which leads to loss of sensation in the skin. Those affected by leprosy also suffer from muscle weakness which leads to progressive debilitation. Long term leprosy patients may sometimes lose the use of their feet and hands.

Children are more prone to getting this disease, which is caused by the organism Mycobacterium leprae. The incubation period is rather long, and this makes it difficult to find out when and where the infection occurred.

Reasons for Lepromin Skin Test

Those who suffer from the following symptoms should get the test done, since it indicates that they may have contracted leprosy:

  • Skin lesions or dermatitis that does not heal for weeks and months.
  • Skin lesions that are lighter than the normal color of your skin, and have less sensation to pain, heat and touch.
  • Absence of sensation or numbness in the arms, hands, feet and legs.
  • Gradual weakening of the muscles such as a foot drop (in this, the toe drags when the foot is lifted to take a step,)

Types of Leprosy

The two common forms of leprosy are lepromatous and tuberculoid. In both forms sores appear on the skin, but in the former they are larger (in the form of bumps and nodules) and more disfiguring.

Importance of the Test

This test helps to distinguish tuberculoid from lepromatous leprosy. If left untreated, leprosy can be very disfiguring, and it is essential to get an early diagnosis, followed by proper treatment.


A tiny sample of leprosy antigen is injected under the skin, usually in the forearm. The skin gets pushed up, forming a small bump. This is an indication that the antigen has been injected to the correct depth.  The site of the injection is marked, and is examined for reaction, first after 3 days and then again after 28 days.

There may be a slight burning or stinging sensation. Some may also experience a slight itching at the injection site after a few days. There is usually no risk involved, and it is only in rare cases that an allergy in the form of hives may appear.