Human gnathostomiasis (nodular migratory eosonophilic panniculitis)

A 42-year-old woman was first seen in January 1996 with a 7-cm diameter erythematous-edematous, pruritic plaque on her right shoulder. The lesion had first appeared 3 weeks previously on the right side of the thorax and migrated to the shoulder. The patient had eaten raw fish (sashimi) in Japanese restaurants two or three times a year during the past few years. The presence of a migrating, pruritic, erythematous, and edematous plaque was clinically suggestive of nodular migratory eosinophilic panniculitis, also known as deep larva migrans or gnathostomiasis. The suspicion was further strengthened by the presence of 12% eosonophilia in the blood cell count. The patient was given albendazole, 400 mg/day for 7 days. Seven days after treatment, the lesion disappeared. Three months later the patient returned with a new lesion that had evolved over 1 month, similar to the previous one, but on the left side of the thorax. This time there was no history of the ingestion of raw fish, and therefore a relapse of gnathostomiasis was suspected. The patient was given 200 μg of ivermectin orally for two consecutive days. Again, 1 week after treatment the lesion disappeared, only to relapse 2 months later. This time the lesion evolved over 12 h. When the patient was seen, a 2-cm diameter excoriated, urticaria-like, pruritic nodule was present in the left scapular area (Fig. 1A). In an attempt to remove the parasite, a deep, 8-mm punch biopsy was performed in the center of the lesion. A sagittal cut of the complete parasite was present in one of the histopathologic slides (Fig. 1B). Based on the epidemiologic and morphologic characteristics, the parasite was classified as Gnathostoma spingerum. After removal of the parasite, the patient has remained free of symptoms for over 2 years.