Atypical manifestations of tegumentary leishmaniasis in a transmission area of Leishmania braziliensis in the state of Bahia, Brazil

Summary

American tegumentary leishmaniasis (ATL) can occur in different forms, classically categorized as cutaneous leishmaniasis (CL), mucosal leishmaniasis (ML), diffuse cutaneous leishmaniasis and disseminated leishmaniasis. Atypical ATL have been described in sporadic case reports. In this study we analyzed the presence of atypical manifestations (vegetative, verrucous, crusted and lupoid) among a cohort of all patients presenting to the Health Post of Corte de Pedra. Among 1396 patients diagnosed with ATL in 2005–06, 35 (2.5%) patients presented with atypical manifestations of the disease. Of these patients, 14 were pregnant women, 2 were co-infected with HIV, and 19 had no comorbidity or other apparent risk factors for the development of atypical ATL. These 19 patients were the focus of this study. They were predominantly adult males, frequently presenting with facial lesions (p< 0.001 OR=17.5 CI 95% 6.1 – 52.4) and had higher rates of treatment failure with antimony therapy (p< 0.001 OR= 327 CI 95% 45 – 6668) when compared with patients with classic ATL attended in the same period.

Introduction

Leishmania (Viannia) braziliensis is the most important causal agent of American tegumentary leishmaniasis (ATL) in Northeastern, Brazil and cutaneous leishmaniasis (CL), is most commonly characterized by a single or few, well-delimited ulcers with elevated borders on the lower limbs^1,2. Mucosal leishmaniasis (ML) occurs in approximately 3% of CL patients and involves the nasal mucosa in the majority of cases^3,4. Disseminated leishmaniasis (DL) has been emerging in the endemic area, and the number of documented cases has increased by more than 10 fold in the last 20 years⁵. DL is characterized by the presence of ten or more acneiform papules and ulcerated skin lesions, in at least two different parts of the body⁵. We have recently reported that pregnancy was associated with large, exuberant, and exophytic cutaneous lesions⁶. In this study, we describe the clinical characteristics of 19 cases with atypical ATL without apparent risk factors for this form of disease. We compare clinical manifestations, the immunologic response, and the response to antimony therapy in the patients with atypical ATL versus patients with classic ATL.

Materials and Methods

Subject Selection and clinical evaluation

All patients presenting to the leishmaniasis clinic of Corte de Pedra, Bahia, Brazil, with diagnosis of ATL between January 2005 and December 2006 participated in this study. The diagnostic criteria were parasite isolation in culture or positive delayed type hypersensitivity (DTH) reaction with leishmania antigen and compatible histopathological findings. Atypical ATL was defined by the presence of unusual lesions such as vegetative, verrucous, crusted and lupoid lesions. This group was compared to patients with classic CL and DL considered here as classic ATL. Clinical data, such as possible comorbidities and use of immunossupressive drugs, were collected from all patients. Serologic tests for Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), Hepatitis C Virus (HCV), and Human T-Cell Lymphotropic Virus Type 1 (HTLV-1), were performed as well as tests of blood glucose levels, blood urea nitrogen (BUN), and hepatic enzymes. Written informed consent was obtained from all adult patients and from parents or guardians of minors and all patients photographed gave permission to publish the pictures. The study was approved by the Ethical Committee of the Federal University of Bahia that is responsible to evaluate and approve scientific studies performed in the clinic of Corte de Pedra.

Diagnosis of leishmaniasis

DTH skin testing was performed with leishmania antigen as described previously⁷. The test was considered positive when the induration was ≥ 5mm. A 4-mm punch biopsy was performed at the border of skin lesions and a fragment was analyzed in the pathology department of the Professor Edgard Santos University Hospital, in Salvador, Brazil. Parasite culture was performed from samples obtained by needle aspiration.

Immunologic Studies

Cytokines were determined in supernatants of peripheral blood mononuclear cells (PBMCs) after 72 hours of stimulation with L. braziliensis antigen as previously described⁸. IFN-γ and TNF-α were measured using the ELISA sandwich technique (R& D Systems, Minn., MN), and the results were expressed in picograms per milliliter on the basis of a standard curve generated by use of recombinant cytokines.

Treatment

All patients were treated with meglumine antimony in a dose of 15–20mg/Kg/day intravenously for 20 to 30 days. Patients who presented with two consecutive failures of treatment were treated with a third course of meglumine antimony IV plus pentoxilifylline 400mg PO three times a day for 20 to 30 days, or amphotericin B 0.5mg/Kg/day IV three times weekly until the total dose ranging from 1.0g to 1.5g.

Results

During the period of 24 months, 1396 patients were diagnosed with ATL in the clinic, 35 of whom presented with atypical ATL. Those patients were divided in three groups: pregnant women (n=14), as described in a previous study⁶, patients co-infected with HIV (n=2) and patients with atypical ATL (n=19) without clinical comorbidities. These 19 patients were predominantly young adult male (84%). The majority of the cases had 3 or less lesions. In the patients with atypical ATL, the lesions were exophytic, without clear borders and were sometimes crusted. They also had a tendency to bleed when touched (Figure 1). The DTH reaction to leishmania antigen was positive in the majority of the patients and the frequency of positive culture for leishmania was consistent with previous observations in our routine work in this Health Post. In all 8 patients in which parasites were isolated, they were identified as L braziliensis. In the group of atypical ATL, only three patients healed their lesions with antimony alone. Although, two of these required 3 courses of meglumine antimony to achieve cure. Two patients healed when treated with meglumine antimony and pentoxifylline, which was introduced following treatment failure with three courses of antimony. Thirteen cases healed with amphotericin B, introduced after failure of three or more courses of antimony. One patient was treated initially with amphotericin B due to an allergy to antimony. The histopathology of atypical ATL lesions showed an infiltration of lymphocytes and plasma cells with few or the absence of parasites. In all 19 patients, the laboratory studies didn’t show any kidney dysfunction, liver enzymes alterations or abnormalities in blood glucose level. All serologies for HIV, HTLV, HBV and HCV were negative.

Figure 1.

A Patient with verrucous lesions, without clear borders, positive DTH, and culture isolate Leishmania V. braziliensis; B Patient with exophytic, verrucous and crusted lesion of the nose and with positive DTH and positive culture; C Patient with lupoid lesion on face, positive DTH and positive culture.

In Table 1, the clinical data of the 1361 classic cases of ATL were compared to the 19 atypical patients. The age of atypical patients ranged from 14 to 55 years (33 ± 11.7) and did not differ from the patients with classic ATL (23 ± 17.6). The atypical patient group had a male to female ratio of 5.3:1 as compared to 1.8:1 (p=0.098) in the classic ATL group. Lesions above the waist were much more frequent in the atypical group (p < 0.001). Moreover, while 68% of the atypical ATL patients had lesions on the face, only 11% of those with classic ATL cases had lesions on the face (P< 0.001 OR=17.5 CI 95% 6.1 – 52.4). Three patients (15.7%) in the atypical group developed mucosal lesions concomitantly that were contiguous with the skin lesions. No differences were seen between the two groups regarding the response to the skin test. Additionally, in five atypical patients, IFN-γ levels (10434 ± 6886pg/ml) were measured in supernatants of lymphocyte cultures stimulated with L. braziliensis antigens, and concentrations of this cytokine were similar to that observed in patients with classic CL (5174 ± 6582pg/ml) (P=0.19). There was also no difference in TNF-α levels (P=0.15). Patients with atypical ATL had a higher rate of treatment failure with antimonials (P< 0.001 OR= 327 CI 95% 45 – 6668) when compared with patients with classic lesions treated in the same period.

Table 1.

Comparison between patients with atypical lesions and patients with classic lesions of ATL

	Classic ATL (1361)	Atypical ATL (19)	P	OR (CI 95%)
Male %	64,6%	84.2%	0.091
Age ±SD	27±17.6	33±11.7	0.098*
DTH/average mm	17±5.8	15±5.3	0.167*
DTH neg	3.9%	11.7%	0.147#	2.4 (0.0 – 13.6)
Lesion in face	11%	68%	< 0.001#	17.5 (6.1 – 52.4)
Lesions above the waist	27%	79%	<0.001#	10 (3.3 – 30.4)
Antimony failure§	5.2%	94.7%	< 0.001#	327 (45 – 6668)

^*Student’s T test

^#Fisher’s Exact Test

^§≥ three courses of meglumine antimony

Discussion

Reports of atypical forms of ATL have been described sporadically^9–12. Herein, we described the frequency of atypical forms of ATL in a large cohort and compared clinical and immunologic characteristics of 19 patients with atypical ATL compared to those with classic ATL diagnosed in the study period.

Classic CL is characterized by a well-defined ulcer with raised borders. DL presents with more than 10 multiple acneiform and small papular lesions in different areas of the body that eventually ulcerate⁵. The atypical ATL patients had a clinical presentation quite distinct from CL and DL. The majority of patients had a small number of lesions, but their characteristics were different from the ulcerated lesion observed in CL. Although two atypical ATL patients had a very high number of lesions similar to the DL cases, in these patients, the disease was concentrated in only a few areas of the body where lesions became confluent.

The host immunological response plays a pivotal role in the outcome of leishmania infection. In the absence of a protective type 1 immune response, patients infected with L. amazonensis develop diffuse cutaneous leishmaniasis characterized by nodular lesions with abundant macrophages containing leishmania¹³. In contrast, patients with a dominant type 1 immune response present with localized ulcerated lesions^{14, 15}. The histopathology of atypical lesions was similar to those found in classic CL. Moreover, the majority of these patients had a positive leishmania DTH test and in all cases in whom in vitro immunological study was performed there was a dominant type 1 immune response. Thus, we conclude that there was no data indicating that the clinical manifestations presented by these patients were associated with a specific impairment in the host immunological response.

Vectors and parasite factors may influence the outcome of leishmania infection. The observation that the atypical ATL occurs predominantly in adult males suggests a potential role for environmental factors. In such cases, intra-species differences among leishmania^{16, 17} and the influence of vector species in disease outcome should also be considered. We did not find a cluster of atypical cases in a specific geographical location within the endemic area, but the small numbers of cases limited the power of the study to evaluate this variable. In a recent report of atypical forms of leishmaniasis in Pakistan, a cluster of cases in a geographically restricted area was observed¹⁸.

The major finding of this study was the identification of a distinct and emerging form of leishmaniasis characterized by atypical lesions. For clinicians and infectious diseases specialists, the clinical description of atypical leishmaniasis is even more relevant, as such presentations are not depicted in textbooks. It is furthermore critical in order to accurately diagnose atypical ATL and appropriately treat these patients. Since patients with atypical ATL had a poor response to antimony therapy, we recommend that amphotericin B be considered as the drug of choice for all patients diagnosed with atypical ATL.