Cutaneous leishmaniasis in a globetrotting explorer

Description

A 73-year-old retired man presented to his general practitioner (GP) in the UK with a 4-month history of non-healing lesion on the base of his right thumb and, subcutaneous nodules running up the forearm. The patient was an extensive world traveller where he was exposed to fresh water and opportunistic pathogens during expeditions to Asia, Africa and the Americas. Initially, he experienced itching to the hand with progression to a small, painless pustule that he noticed for 3 months while in Bangladesh. His GP attempted to treat the lesion with oral flucloxacillin, which had no effect. Following a more detailed travel history the patient was referred to infectious disease medicine.

On physical examination there was a well demarcated erythematous patch of 4 cm in size with central ulceration of 1 cm on his right dorsal first metacarpal phalangeal joint area (figure 1A). Although, there was no evidence of lymph node involvement, multiple subcutaneous nodules were palpable (figure 1B).

Figure 1.

(A) Clinical image of cutaneous leishmaniasis. Non-tender erythematous skin changes with central ulcer. (B) Subcutaneous nodules felt at arrow positions along the arm.

A superficial biopsy of the skin revealed epidermal hyperkeratosis and ulceration, with suppurative epithelioid granulomas and occasional histiocytic multinucleated giant cells seen in the dermis and up to the deepest part of the biopsy (figure 2). One giant cell at the edge of the ulceration contained basophilic small structures within cytoplasm, which was the first indication of degenerate Leishmania amastigotes.

Figure 2.

Histopathological features of patient infected with cutaneous leishmaniasis: epithelioid granulomas and occasional histiocytic multinucleated giant cells (arrow) seen in the dermis. H&E staining.

No fungi, acid fast bacilli or other bacteria were seen on the giemsa, Periodic acid–Schiff–diastase stain (PAS-D), gram, Wade-Fite and Zeil Neelson stains. Leishmania major DNA was detected on PCR and confirmed a diagnosis of cutaneous leishmaniasis (CL).

The patient had a complete spontaneous resolution within 6 months and he did not require any treatment. This was a fortunate outcome as other Leishmania species, such as Leishmania braziliensis, can take up to several years to heal. He was seen by dermatology and infectious disease for several months then was discharged.

Leishmania is a vector-born protozoan whose clinical spectrum ranges from asymptomatic infection to fatal visceral leishmaniasis.¹ Over the last decade, an increase in imported CL cases to developed, non-endemic countries have been reported in international literature, this is observed among migrants, travellers and military personal. The WHO lists leishmaniasis as a neglected tropical disease with an estimated 600 000–1 million new cases of CL worldwide per year.² Practitioners in Europe should note that the Mediterranean Basin in Southern Europe has experienced an increase in cases with dogs or other synanthropic mammals proving to be reservoir hosts. CL has great capacity to mimic other dermatoses, and can mislead practitioners especially in non-endemic regions. This can result in untreated lesions that cause scars or potential disease progression.³

Patient’s perspective.

The area around the bite healed considerably but the nodular lesions have spread further up my arm and was considering intravenous treatment but was concerned about the toxicity affecting my heart. Fortunately, it all healed up. I hope to continue to travel the globe.

Learning points.

• Travel history is important part of the diagnostic process and leishmaniasis should be suspected with compatible examination features.

• Travellers, researchers, military personnel who are likely to be exposed to sand flies should receive advice regarding leishmaniasis and appropriate protective measures.