Keywords: Dermatology; Infestation; Myiasis; Parasitosis

Case Report

A 90-year-old male patient with a history of chronic hypertension, came to the infectious disease outpatient clinic at our institution, with a 25 years’ history of chronic ulcer at the external malleolus of the right leg, for which he has received multiple topical treatments without complete healing. On questioning, he reported having had increased pain over the past 2 months, associated with erythema, fever and purulent secretion through the ulcer. On physical examination he was malnourished but not toxic, without respiratory difficulty, no pulmonary or cardiac abnormalities were found on auscultation, the abdomen was normal to palpation without abnormal masses, but on the external malleolus of the right leg, he had a 7x5 cms varicose-like ulcer, with purulent fetid secretion, necrotic tissue and from which sprouted abundant larvae consistent with Cochliomyia hominivorax myiasis (Figure 1A and video clip). He was taken into surgery to perform a thorough debridement of the ulcer, with complete extraction of all larvae and tissue culture, from which E.coli and P.aeruginosa were isolated, and then he received a single dose of Ivermectin (200 mcg/kg PO) and 7 days of Piperacillin/tazobactam, showing clinical improvement but no complete healing (Figure 1B).

The term myiasis refers to ectoparasitic infestation of live human and vertebrate animals with dipterous (two-winged) larvae (maggots) which, at least for a certain period, feed on the host's dead or living tissue, liquid body-substance, or ingested food [1]. Myiasis is the fourth most common travel-associated skin disease and cutaneous myiasis is the most frequently encountered clinical form [2]. Cutaneous myiasis can be divided into three main clinical manifestations: furuncular, creeping (migratory), and wound (traumatic) myiasis. Human myiasis has worldwide distribution, with more species and a heavier burden in tropical and subtropical countries. In recent years with increased travel to the tropics, myiasis has become common in returning travelers from these regions [3,4].

Figure 1A: Varicose-like ulcer at the external malleolus of the right leg, with multiple larvae consistent with Cochliomyia hominivorax myiasis.

Figure 1B: Leg ulcer after treatment.

Video clip: Live images of the moment the ulcer is discovered showing the larvae.

1. Solomon M, Lachish T, Schwartz E (2016) Cutaneous Myiasis. Curr Infect Dis Rep 18: 28.
2. Robbins K, Khachemoune A (2010) Cutaneous myiasis: a review of the common types of myiasis. Int J Dermatol 49:1092-1098.
3. Krajewski A, Allen B, Hoss D, Patel C, Chandawarkar RY (2009) Cutaneous myiasis. J Plast Reconstr Aesthet Surg 62: e383-e386.
4. McGraw TA, Turiansky GW (2008) Cutaneous myiasis. J Am Acad Dermatol 58: 907-926.