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A 66-year-old male traveller returning from Costa Rica presented with a 4-week history of a gradually enlarging painless boil above the lateral malleolus of his right ankle. He was systemically well, and had no recollection of an insect bite. Examination revealed a 2 cm furuncle (fig 1A) with two central pores. When occluded, a breathing tube extended through the larger pore. Figure 1 (A) A 2 cm furuncle seen above the patient’s right ankle. (B) Removal of insect larva after application of petroleum jelly and Tegaderm. We applied petroleum jelly and Tegaderm to both breathing holes. After 2 h, the breathing tube and abdomen of an insect larva was exposed and removal was possible with forceps (fig 1B). Ultrasound demonstrated connecting tracks extending from each pore, but no further larvae (fig 2A). Oral co-amoxiclav was administered to prevent secondary bacterial infection; the patient reported complete resolution of the lesion. Microbiology identified a larva of Dermatobia hominis, the human bot fly (fig 2B). Figure 2 (A) Ultrasound of the lesion after removal of the larva demonstrated two fluid filled tracks but no further larvae. (B) The extracted larva of Dermatobia hominis, the human bot fly. Furuncular myiasis is an infestation of the skin with highest incidence in the tropics. In Mexico, Central and South America, the commonest fly causing human infestation is D hominis.1 Adult female flies lay eggs on the abdomen of blood-sucking arthropods such as mosquitoes. Exposure of the insect to local warmth during feeding causes the eggs to hatch and drop to the skin of the mammalian host, followed by larval penetration.2 Patients typically report an apparent insect bite that slowly enlarges over time to a nodule measuring 1–3 cm in diameter. Removal of the intact larva is curative, although infestation may be complicated by secondary bacterial infection.1

One of the authors suffered “black toe” on a skiing trip.1 Vigorous fore-aft movements of the feet caused the halluces to strike repeatedly the ends of the ski boots resulting in recurrent micro-trauma and, eventually, subungual haematoma formation and onycholysis. Examination 3 months later revealed the nail of the right hallux to have developed a green discolouration accompanied by non-tender paronychia (fig 1). Microscopy and …