A 45-year-old marine biologist presented to ourtravel clinic complaining of two painful skin swellings aweek after returning from a hiking trip in the rain for-est of Belize. Except for the dull pain and intense itch-ing around the swelling, the patient was feeling well.Hereported no fever.He also had multiple insect bite markson his back, neck, and extremities.

On examination, two furuncles, each 2 cm in size,were noticed in his right shoulder and scalp.There wereno visible overlying skin abrasions, but the skin wasinflamed and red around the swelling.The lesion was ten-der on palpation, and there was a small, central darkpoint at the shoulder lesion. Using K-Y Jelly (lubri-cant), the punctum was occluded and soon a larva startedto emerge. Holding and pulling the tip with a forcepsfailed to extract the larva.By making a small incision acrossthe punctum and applying a gentle pulling pressure, thecomplete larva was extracted (Figure 1A).Two days laterthe second larva was extracted using the same tech-nique (Figure 1B).

Discussion

Myiasis is the invasion of a human or other domes-ticated vertebrate animal by fly larvae of the order

Diptera.1,2 Despite the presence of many species, thetwo common flies that affect returning travelers from thetropics are Dermatobia hominis (the human botfly) andCordylobia anthropophaga (the tumbu fly).3The larva stageof both species can only survive in the tissue of verte-brate animals. D. hominis is endemic in the humid trop-

Dawd S. Siraj, MD, MPH&TM: Assistant Professor ofMedicine, Department of Infectious Diseases, Head, ECUInternational Travel Clinic, East Carolina University, BrodySchool of Medicine, Greenville, NC, USA; Joseph Luczkovich,PhD: Associate Professor of Biology, Department of Biology,Institute for Coastal and Marine Resources, East CarolinaUniversity, Greenville, NC, USA.

Reprint requests: Dawd S. Siraj, MD, MPH&TM, Departmentof Infectious Diseases, ECU International Travel Clinic, EastCarolina University, Brody School of Medicine, Greenville,NC, USA 27858–4354.

J Travel Med 2005; 12:XXX–XXX.

Nodular Skin Lesion in a Returning TravelerDawd S. Siraj and Joseph Luczkovich

As tropical countries become common travelers’ destination, more and more returning travelers are expected to pres-ent with cutaneous lesion secondary to myiasis. The skin lesion starts as a small red papule and gradually enlarges tobecome a furuncle. Familiarity with the characteristic clinical presentation and proper management would avoid an unnec-essary diagnostic workup and therapeutic intervention, including surgery and the use of antibiotics.

1

A

B

0 1 Second-stage larva of Dermatobia hominis extracted fromshoulder (A) and scalp (B) lesions. Note the parallel concen-tric rows of spine (�17 magnification). The scale in image Bindicates centimeters (long lines) and millimeters (short lines).

ical forests and wooded lowlands of Central and SouthAmerica. C. anthropophaga is endemic to sub-SaharanAfrica.4,5The female D. hominis fly seeks a biting arthro-pod and attaches the fertilized eggs to the abdomen ofthe carrier insect to use it as a mechanical vector. Oncethe insect lands on a vertebrate, the eggs are released; theythen hatch into first-stage larvae.The larvae burrow intothe subcutaneous tissue and mature to flask-shaped sec-ond-stage larvae. Subsequently, they undergo one moremolting into fusiform-shaped third-stage larvae.The lar-vae have distinctive posteriorly directed black hookletsaround white abdominal segments,which help to anchorthe larvae within the tissue.6,7The larvae complete theirdevelopment within 4 to 14 weeks, at which time theyemerge from the skin, fall to the ground, and completetheir life cycle.

In case of C. anthropophaga, the female fly lays its eggin soil or drying clothes.Within 1 to 3 days, the eggs hatch,and upon direct contact with humans, the larvae burrowinto the skin. Once in the tissue, the life cycle is similarto that of D. hominis.

A botfly larva produces a painful cutaneous swellingthat looks like a furuncle. Pain and a sensation of move-ment might be felt. Soon an opening becomes apparent,and intermittently the tail of the larva extrudes from thisopening. Occasionally, because of secondary bacterialinfection, there is purulent discharge, suggesting bacte-rial furunculosis.The clinical presentation and appear-ance of the lesion of D. hominis and C. anthropophagaappear similar except that D.hominis favors the scalp, face,and extremities, whereas C. anthropophaga is more likelyto affect the trunk, buttocks, and thighs. Rarely, larvaemigrate to other body sites. Case reports of involve-ment of the eye, urethra, penis, vagina, bladder, colon,upper respiratory tract, oral cavity, and brain have beendocumented.2,8–10

The differential diagnosis of myiasis should includecellulitis, a staphylococcal carbuncle or furunculosis,leishmaniasis, a sebaceous cyst, and an embedded foreignbody.11–13 Clinical recognition of myiasis in a returningtraveler would avoid an unnecessary diagnostic workupand therapeutic intervention, including surgery and theuse of antibiotics.

Removal of the larva by occlusion of the openingusing different ointments is commonly attempted first.Petrolatum,fingernail polish,makeup cream,adhesive tape,and pork fat have all been reported to work.14,15 Occlu-sion of the punctum asphyxiates the larva, which thenprotrudes far enough to be grasped by a forceps. In onecase report, squeezing the lesion was enough to removemultiple larvae.16 Usually,occlusion and extraction takeshours, and it is rarely successful in case of D. hominis.Thismakes surgical evacuation of the larva a necessary step.

Another method involves the injection of lidocainehydrochloride under the nodule.This paralyzes the larvaand makes removal much easier.Additionally, the pres-sure of the injection is sufficient to push the larva out.17,18

Topical administration of 1% ivermectin in propylene gly-col for 2 hours was recently reported to be effective inremoving human myiasis by Cochliomyia hominivorax.19

Systemic ivermectin has been used in the treatment ofD. hominis myiasis in animals.20 In humans systemic iver-mectin might be used when there are many lesions orwhen local occlusion treatment cannot be done easily,as is the case in opthalmomiasis.6 In our patient remov-ing the larva by obliterating the opening was not suc-cessful in either lesion, and incision and widening of theopening had to be done in addition to the applicationof the K-Y Jelly.This was necessary to facilitate extrac-tion of the widened anterior end of the larva as opposedto the narrower protruding posterior end.21 Additionally,the parallel, concentric rows of spine in its body anchorthe proximal end of the larva beneath the skin, makingit difficult to extract by simple pressure alone (see Fig-ure 1).

The application of insect repellents containingdiethyltoluamide and permethrin and the use of mos-quito netting decreases the risk of infestation. In thecase of C. anthropophaga, ironing clothes before wearingthem is an effective method of destroying the eggs.Addi-tional general precautions include the wearing of long-sleeved clothing and avoiding sleeping outdoors.

As tropical countries are becoming common des-tinations for travelers, more and more returnees areexpected to present with cutaneous lesions secondary tomyiasis. Physicians should be familiar with the charac-teristic clinical presentation, diagnosis, and proper man-agement to avoid delayed diagnosis and the unnecessaryuse of antibiotics.

Declaration of Interests

The authors have no financial or other conflicts ofinterest to disclose.

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Sira j e t a l , Nodular Sk in Les ion in a Return ing Trave ler 3

Devastation on an island called Nias in Indonesia—sole survivor in a village. Submitted by Marc Shaw.