Myiasis

September 14, 2005
Joe Monroe, PA-C

The parents of a 12-year-old sought a consultation for the “cyst” that had appeared on their daughter's lower back. The lesion was first noticed 2 months earlier upon the child's return from a trip to Belize.

The parents of a 12-year-old sought a consultation for the “cyst” that had appeared on their daughter's lower back. The lesion was first noticed 2 months earlier upon the child's return from a trip to Belize.

On examination, writes Joe R. Monroe, PA-C, of Vancouver, Wash, the eruption was noted to have a rather large (3-mm) punctum overlying a 3-cm area of tumefaction. A little prodding appeared to provoke movement inside the lesion (A). The relative rarity of a cyst occurring in a child, the unusually large punctum, and the history of travel to Belize raised the suspicion of myiasis. Excision and pathologic evaluation confirmed this diagnosis.

Myiasis is caused by the botfly larva of Dermatobia hominis. Apparently, the botfly lays its eggs on a mosquito, which deposits them on the human host where they penetrate the skin.

Frequently, this occurs at multiple sites on the body. It has been said that as an alternative to surgical removal, a strip of bacon or dab of petroleum jelly placed on the punctum will induce the maggot to back out of the skin completely.1

As seen here, the maggot was embedded in the excised tissue (B). Surgical removal of the maggot was curative, and the patient's recovery was uneventful.

REFERENCES:1. Fitzpatrick TB, Johnson RA, Polano MK, et al. Color Atlas and Synopsis of Clinical Dermatology: Common and Serious Diseases. 3rd ed. New York: The McGraw-Hill Companies; 1997:861.

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