Dhir et al. Journal of Medical Case Reports 2010, 4:209 http://www.jmedicalcasereports.com/content/4/1/209 Page 2 of 3 Figure 1 Appearance of the left optic disc on presentation (swol- len). Figure 3 Resolution of left optic disc edema after treatment with ivermectin. High magnification. Visual symptoms, skin lesions and optic disc edema resolved over the course of two to three weeks. On last review, visual acuity was 6/6 in both eyes, color vision and visual fields were normal and there was complete res- olution of disc edema (Figures 2 and 3). Discussion To the best of our knowledge, no case of cutaneous larva migrans associated with isolated optic disc edema has been reported in literature. The authors feel this may be a case of optic perineuritis (peri-optic neuritis). On the other hand, diffuse unilateral sub-acute neuroretinitis (DUSN) is well described. DUSN is an ocular infectious disease caused by either of two different sized and as yet unidentified nematodes Figure 2 Resolution of left optic disc edema after treatment with ivermectin. Low magnification. capable of causing profound visual loss in one or both eyes. The smaller nematode measures 500 to 600 microns in length and is likely to be Ancylostoma caninum, the dog hookworm and common cause of cutaneous larva migrans or the larval form of Toxocara canis [2]. The larger nematode measures 1000 to 2000 microns and is believed to be Baylisascaris procyonis, the raccoon roundworm. DUSN causes uniocular persistent vitritis associated with papillitis, retinal vasculitis and multifocal lesions involving the outer retinal layers. In late stages, optic disc and retinal atrophy may occur. Oral high dose albendazole [1,3], thiabendazole or a single oral dose of ivermectin [4] has been used for effective anti-helminthic therapy. Alternatively, the nematode can be directly destroyed with argon laser photocoagulation. A scanning laser ophthalmoscope has been used to assist identifica- tion of the live nematode [5]. We believe the causative organism in our patient with optic disc edema is likely to be A. caninum due to the fact that he had classic lesions of cutaneous larva migrans and as other investigations were normal. We can speculate that an A. caninum larva migrated into or close to the optic nerve, causing perioptic neuritis. The ocular symp- toms preceded systemic treatment with ivermectin, and therefore cannot be drug-induced. There were no other findings of DUSN and the clinical course was good, with no involvement of the retinal vasculature or outer retina. Although he presented late, cure was achieved with a sin- gle dose of oral ivermectin. Conclusions This case highlights the importance of taking relevant history of recent travel to endemic areas affected by the nematodes in patients presenting with optic disc edema, and pertinent questioning regarding non-ocular symp-