Pets often defecate into childrens sand boxes, which transfers the eggs of certain cat or dog hookworms into the sand. From the point of entry they worm their way under the skin in a wandering track that is red, raised, and very itchy. Infective larvae of cat and dog hookworms, Ancylostoma braziliense and Ancylostoma caninum , are the usual causes. Other skin-penetrating nematodes are occasional causes.
Treatment is pretty simple if there are just one or two worm tracks.
Alternatively, the older treatment can be used, which consists of spraying ethyl chloride on the skin just ahead of where the track seems to be going, freezing and killing the larva. If there are multiple tracks, oral ivermectin, an antiparasitc drug, is given in a single dose. Ivermectin can also be used to treat drug resistant head lice. Wash you hands after handling pets, and keep puppies and kittens dewormed. Your veterinarian is your best source of information to prevent these sorts of infections, and can test and treat your pets.