Correspondence

Cellulitis Due to Botfly Larvae

N Engl J Med 1997; 337:429-430August 7, 1997

Article

To the Editor:

I report a case of cellulitis complicated by what turned out to be botfly larvae.

A 36-year-old woman presented with erythema, swelling, and pain in both shins. The lesions had developed two weeks after she returned from Peru. Cellulitis was diagnosed, and cephalexin was prescribed. The cellulitis improved somewhat, but two weeks after the initial presentation new lesions developed. On examination, the patient had seven tender, erythematous, indurated subcutaneous lesions 2 to 3 cm in diameter, each with a central punctum. A course of dicloxacillin was started. The same night, the patient saw a larva crawl out of a lesion (Figure 1Figure 1Botfly Larva from the Patient (×75).). She called for advice and was told to apply petroleum jelly to force the other larvae out for air. She tried this briefly, but became impatient and eventually squeezed out the larvae manually. She obtained a total of seven larvae in this manner, which were identified as Dermatobia hominis, commonly called the human botfly.

D. hominis has a fascinating life cycle.1 It is found widely in humid areas of Mexico, Central America, and South America. Its larvae can survive only in vertebrate tissue; infestation with them is known as myiasis. The adult female botfly deposits eggs on the abdomen of a bloodsucking fly or mosquito, which in turn deposits the eggs on an animal host. The growth of each larva can provoke severe ulceration and secondary infection. Once mature, the larvae erupt through the host's skin and fall to the ground, where they develop into pupae and subsequently into adult flies.

Myiasis has been reported previously,2-4 but this case was remarkable in two respects. The first was that multiple larvae were present. Previous reported cases have involved infestations of at most a few larvae each. The presence of seven larvae in this patient should alert practitioners to look for multiple sites of infestation.

The second interesting aspect was the mode of treatment. Standard recommendations are to apply petroleum jelly or raw meat to draw the larvae out,5 or to extract them with mosquito forceps. Nowhere does the literature recommend simply squeezing them out. In fact, one may wonder whether such an approach might worsen the problem by crushing the larvae. However, in this patient the procedure was expedient and effective for all seven lesions, and she recovered without sequelae.

Rachel L. Chin, M.D.
San Francisco General Hospital, San Francisco, CA 94110

5 References

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   File TM Jr, Thomson RB Jr, Tan JS. Dermatobia hominis dermal myiasis: a furuncular lesion in a world traveler. Arch Dermatol 1985;121:1195-1196
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   Arthropods and human disease. In: Markell EK, Voge M, John DT. Medical parasitology. 7th ed. Philadelphia: W.B. Saunders, 1992:353-6.
   

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   Minton SA, Bechtel HB. Arthropod envenomation and parasitism. In: Auerbach PS, ed. Wilderness medicine: management of wilderness and environmental emergencies. 3rd ed. St. Louis: Mosby, 1995:755-7.
   

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Citing Articles (3)

Citing Articles

1. 1

   D KROSHINSKY, M GROSSMAN, L FOX. (2007) Approach to the Patient With Presumed Cellulitis. Seminars in Cutaneous Medicine and Surgery 26:3, 168-178
   CrossRef

2. 2

   Dawd S. Siraj, Joseph Luczkovich. (2005) Nodular Skin Lesion in a Returning Traveler. Journal of Travel Medicine 12:4, 229-231
   CrossRef

3. 3

   Joanne Gilbert, Lucia Lazio. (1999) Managing Congestive Heart Failure With Thoracic Electrical Bioimpedance. AACN Clinical Issues: Advanced Practice in Acute and Critical Care 10:3, 400-405
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