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Sub-polar lepromatous leprosy localized to the face

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Sub-polar lepromatous leprosy localized to the face
Mamatha George MD, Uma Rajan MD, Sandhya George MD, Jaheersha Pakran MD, Sumi Thomas MD
Dermatology Online Journal 16 (9): 8

Calicut Medical College


Leprosy is an infectious disease characterized by a wide spectrum of clinical manifestations, ranging from tuberculoid to lepromatous disease with immunologically unstable borderline forms in between. In clinical practice cases often do not conform to a classical textbook description, which may lead to misdiagnosis if not properly investigated. A 22-year-old patient presented to us with erythematous plaques localized to the face. Slit skin smear for Mycobacterium leprae was positive from lesional as well as non-lesional skin. A biopsy from a plaque showed diffuse atrophy of the epidermis with a subepidermal cell free zone (grenz zone). The cellular infiltrate was composed of foamy macrophages admixed with lymphocytes in the dermis. Fite-Faraco staining revealed clumps of acid-fast bacilli within the macrophages. Based on the skin smear and histopathology findings, a diagnosis of sub-polar lepromatous leprosy was made and the patient was started on multidrug therapy. The exact pathogenesis of localized multibacillary disease is not known. Our case highlights the importance of skin smear and biopsy in all suspected cases of Hansen disease. We conclude that routine skin smear in all new leprosy cases is mandatory to differentiate localized multibacillary cases from paucibacillary cases for the purpose of accurate categorization and treatment.


There is no human infectious disease in which the clinical picture is as varied as that of leprosy [1]. The wide spectrum of clinical manifestations range from tuberculoid to lepromatous with immunologically unstable borderline forms in between; this spectrum is determined by the immune status of the host. Therefore, an understanding of the spectral concept is essential if one is to be aware of the diversity of clinical features so that a correct diagnosis can be made [1]. The lepromatous end of the leprosy spectrum commonly presents as numerous symmetrical macules, papules, plaques, or nodules, often associated with multiple nerve involvement. Variants of lepromatous leprosy include Lucio leprosy and histoid leprosy. A relatively rare presentation of lepromatous leprosy is the solitary skin lesion with a high bacterial count. We are reporting a patient who presented with skin lesions localized to face, which later proved to be sub-polar lepromatous leprosy based on investigations.

Case history

A 22-year-old male residing in a low endemic area in Kerala, a state in south India, presented with asymptomatic reddish plaques on the right cheek, which started as a small papule 6 months back and progressively increased to the present size. The patient gave no history of any preceding trauma or insect bite. History of contact with leprosy cases could not be elicited. On examination there were multiple erythematous plaques over the right side of face (cheek, pre-auricular region, bridge of nose, and upper eyelid) of size ranging from 1 cm to 5 cm with doubtful impairment of sensation (Figure 1). The largest plaque showed a punched out center. There were no other skin lesions. Examination of peripheral nerves revealed a thickened and non-tender greater auricular nerve on the right side. With the differential diagnosis of borderline tuberculoid leprosy, sarcoidosis, and lupus vulgaris, we further investigated the patient.

Figure 1
Figure 1. Erythematous plaques on the right cheek, pre-auricular area, bridge of nose.

Slit skin smear for Mycobacterium leprae revealed that the bacterial index (BI) was 6+ from the ear lobes and lesion, but it was 1+ from the normal looking skin over the dorsa of fingers. Morphological index (MI) was 15 percent and 12 percent from earlobes and lesional skin. respectively. Hemogram and other routine biochemical investigations were normal. A biopsy from a plaque showed diffuse atrophy of the epidermis with a subepidermal cell-free zone (grenz zone). The dermis showed a cellular infiltrate composed of foamy macrophages admixed with lymphocytes (Figure 2). Fite-Faraco staining for acid-fast bacilli revealed clumps of bacilli within the macrophages (Figure 3). Based on skin smear and histopathology findings, a diagnosis of sub-polar lepromatous leprosy was made.

Figure 2Figure 3
Figure 2. Biopsy from lesion shows diffuse atrophy of epidermis with a sub-epidermal cell-free zone (grenz zone). Dermis shows cellular infiltrate composed of foamy macrophages admixed with lymphocytes. (H&E, x100)

Figure 3. Skin biopsy showing clumps of acid fast bacilli (Fite-Faraco stain, x400)

Multidrug therapy with dapsone, rifampicin, and clofazimine for multibacillary disease was initiated. After 6 months of starting therapy, the patient developed a type 1 reaction. The pre-existing plaque on the face became more erythematous, warm, and tender. Multiple new lesions appeared on the face, arms, and forearms. The patient also developed neuritis in the form of facial palsy. He was started on systemic steroids in a tapering dose, starting with prednisolone 40 mg/day while multidrug therapy was continued unaltered. The cutaneous flaring subsided and the patient recovered from the facial palsy.


Clinically the skin lesion in our patient resembled tuberculoid leprosy, but the bacterial index (BI), morphological index (MI), and histopathology pointed towards sub-polar lepromatous leprosy .The presentation of lepromatous leprosy as a single cutaneous plaque is a rare variant of the disease. Although reports of lepromatous leprosy localized to the extremities have been published earlier [2, 3, 4], to the best of our knowledge this is the first case report of sub-polar lepromatous leprosy presenting as localized lesions on the face.

The exact pathogenesis of such a presentation is not known. Even though the commonest mode of transmission of leprosy is by droplet (aerosols), there are reports of leprosy developing because of inoculation at the sites of tattooing [5], thorn pricks [6], and mosquito bites [7]. Job et al. [3], after evaluating 3 patients with sub-polar lepromatous leprosy, proposed that the clinical and histopathological characteristics of the lesion were the same as those of inoculation lepromas in experimentally infected armadillos. They suggested that in highly susceptible individuals, the infection may be acquired by means of trauma, which lodges a significantly large dose of viable Mycobacterium leprae from the environment into the skin. Kar et al. [8] reported borderline lepromatous leprosy presenting as a single lesion on the glabellar portion of forehead. They concluded that though there was no history of trauma, locally applied sindoor (beautification pigment) might have induced subclinical inflammation leading to entry of Mycobacterium leprae. In our case also we cannot rule out the role of trivial trauma as a possible mode of entry, which may explain the initial localization of multibacillary leprosy.

At present no test has been devised which is superior to clinical examination combined with skin smear for determining the presence of acid-fast bacilli. Our medical and paramedical workers should be well trained with slit skin smear technique to classify cases as paucibacillary and multibacillary for the purpose of adequate treatment. World Health Organization (WHO) Expert Committee in 1988 decided to treat all smear positive cases as multibacillary patients, irrespective of the clinical spectrum [9]. WHO revised this decision in 2009 and recommended that skin smears are not a prerequisite for starting MDT [10].This is regrettable because, as our case demonstrates, multibacillary cases can present with single or a few skin lesions. Thus such cases may receive inadequate treatment leading to further transmission of disease, drug resistance, and disabilities.


Our case highlights the importance of skin smear and biopsy in all suspected cases of Hansen disease. Skin smear may be advised as a routine procedure in all new cases to differentiate multibacillary from paucibacillary cases, because health workers may not be able to differentiate clinically this type of lesion from a tuberculoid plaque.


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2. Yoder LJ, Jacobson RR, Job CK. A single skin lesion--an unusual presentation of lepromatous leprosy. Int J Lepr Other Mycobact Dis. 1985 Dec;53(4):554-8. [PubMed]

3. Job CK, Kahkonen ME, Jacobson RR, Hastings RC. Single lesion subpolar lepromatous leprosy and its possible mode of origin. Int J Lepr Other Mycobact Dis. 1989 Mar;57(1):12-9. [PubMed]

4. Misra RS, Ravi S, Iyengar B, Nath I. A histopathological and immunological profile of a single lesion lepromatous leprosy (LLs). Int J Lepr Other Mycobact Dis. 1991 Dec;59(4):645-8. [PubMed]

5. Ghorpade A. Inoculation (tattoo) leprosy: a report of 31 cases. J Eur Acad Dermatol Venereol. 2002 Sep;16(5):494-9. [PubMed]

6. Job CK, Harris EB, Allen JL, Hastings RC. Thorns in armadillo ears and noses and their role in the transmission of leprosy. Arch Pathol Lab Med. 1986 Nov;110(11):1025-8. [PubMed]

7. Geater JG. The fly as potential vector in the transmission of leprosy. Lepr Rev. 1975 Dec;46(4):279-86. [PubMed]

8. Ranjan Kar B, Belliappa PR, Ebenezer G, Job CK. Single lesion borderline lepromatous leprosy. Int J Lepr Other Mycobact Dis. 2004 Mar;72(1):45-7. [PubMed]

9. World Health Organisation (WHO) Expert Committee on Leprosy. Sixth Report. Geneva, WHO. 1988. 15p.

10. World Health Organisation (WHO). MDT and skin smears FAQ. Geneva, WHO; 2009 [Cited 26 December, 2009].

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