Mr. B, aged 40 years, presented with complaints of a rash that had been present for the past six months. After beginning on his trunk, the rash spread to his arms and legs three months later and his forehead two months after that. Mr. B stated the lesions were growing larger and burning in nature. The patient lived with his wife and three children, and no one else had been ill or had a similar rash.
Mr. B had no chronic health problems or known allergies and was not taking any medications. Having emigrated from the Marshall Islands in the North Pacific Ocean, Mr. B had lived in northeast Iowa for the past five years and had not traveled recently.
The rash consisted of large (15 cm) erythematous plaques with central clearing (Figure 1). Multiple plaques were present on the trunk, neck, and thighs. Smaller lesions were present across the back and forehead.
Initial treatment with antihistamines and topical steroids was unsuccessful. The lesions continued to grow larger and were still painful over the two-month treatment period. Punch biopsies were then obtained from two lesions. Initial pathology indicated granuloma annulare; however, on the recommendation of an astute dermatology consultant, a Fite stain was performed. The Fite stain on the biopsied skin was positive, revealing a diagnosis of granulomatous dermatitis with acid-fast bacterial organisms consistent with cutaneous leprosy.
Leprosy (also known as Hansen disease) is a chronic disease caused by the bacillus Mycobacterium leprae.1 The bacteria multiply very slowly with an incubation period of five to 20 years. Leprosy is not highly infectious. It is transmitted via droplets from the nose and mouth during close and frequent contact with an untreated case. Most individuals (95%) are naturally immune.
Leprosy mainly affects the skin, peripheral nerves, mucosa of the upper respiratory tract, and eyes. If left untreated, the disease can lead to permanent damage of the skin, nerves, eyes and limbs. Early diagnosis and treatment can prevent complications and help eliminate leprosy as a public health concern.1,2
While leprosy remains endemic in some regions of the world, (Angola, Brazil, the Central African Republic, the Democratic Republic of the Congo, India, Madagascar, Mozambique, Nepal, and the United Republic of Tanzania), only about 150 new cases are diagnosed yearly in the United States.1-3 Most of these cases occur in immigrants, but there is an endemic focus in the Gulf Coast region of Texas.4 California, Florida, Hawaii, Louisiana, Massachusetts, New York, and Texas accounted for 65% of cases registered in 2008. Only 16 cases have been reported in Iowa in the past 10 years. Up to 40% of those afflicted identify themselves as Asian or Pacific Islander in national origin.2