Does he have tuberculosis?

A triage nurse comes to get you from  the trauma area because a man in the waiting room says he has tuberculosis.  She wants to know if he should be isolated .  There are no open rooms so you find him in the protocol room.

The pt is a 57 y.o. male with a three week history of a rapidly spreading rash.  He has no cough, no fevers,  and no systemic symptoms.  He has not been losing weight and looks well.  He has the rash shown.  How can you make sense of his claim?

Scroll down for the Case Conclusion












Final diagnosis: Tuberculoid leprosy

Case Conclusion: The patient had a skin biopsy showing acid fast bacilli.

Learning Points: The patient had  “tuberculosis” but not Mycobacterium tuberculosis.  Rather, he had an infection with Mycobacterium  leprae, commonly called leprosy. The word comes from the Latin word lepra meaning scaly.  Leprosy occurs in two forms; Leparomatous leprosy is pictured here which is thought to be evidence of poorer T cell immunity. In those with good cellular immunity, Tuberculoid leprosy occurs as thickened skin plaques with decreased sensation as seen in our patient. 

Leprosy has been described in literature since 200BC when it was described in the Atharava Veda.   Although we commonly find leprosy intropical climates in Brazil, Africa , Indonesia, and India, the cause of leprosy was initially discovered by G.A. Hansen in Norway in 1873. It is a slow-growing, intracellular bacteria that cannot live outside its host and often takes 20 years to produce symptoms.

There was no leprosy in the New World before the arrival of Europeans and it is thought that the Europeans infected armadillos in North America, which have since become the reservoir of leprosy in the US. Genetic sequencing has shown that 64% of humans are infected with leprosy of the same genotype as well as 85% of armadillos.  Red squirrels and three types of primates also can contract leprosy.

Prior to successful treatment with dapsone in 1921, patients were housed in leprosariums. Carville, Louisiana  (shown below) was one of these sites. It was there that a sulfone was first used to treat leprosy in 1941.  Another famous leprosariums was established at Molokai, Hawaii where Father Damien ran a leper colony until he contracted the disease and died.  Dapsone was the first drug used to treat leprosy but resistance developed.  Multi-drug therapy was instituted in1970 and consisted of dapsone, rifampicin, and clofazimine.

The Leprosarium at Carville, Louisiana

The Leprosarium at Carville, Louisiana

Tuberculoid granuloma

Tuberculoid granuloma



Leprosy affects the skin, peripheral nerves, and upper airways with granulomas forming in the tissues. It is thought to be contagious through respiratory droplets. All forms of leprosy may cause some degree of peripheral neurological damage that causes sensory loss in the skin as well as muscle weakness. Long term leprosy can result in amputations of the hands or feet because ulcers worsen on the hands and feet because they are insensate. There is also a cutaneous vasculitis causing ulcers when acid fast bacilli occlude cutaneous blood vessels.  Leprosy also affects the eyes, causing a uveitis and corneal scarring.

There are 5.5 million cases of leprosy world-wide. 

Case Conclusion by Dr. Roseanne Naunheim


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