Common symptoms of tapeworms in dogs include dragging or excessively licking their behinds and the appearance of tapeworm segments in their feces, according to WebMD. A dog infected with tapeworms may vomit or lose weight, even if eating normally.
Pieces of a tapeworm break off into segments as the tapeworm grows inside a dog's intestines, states PetMD. These segments pass through the dog's digestive system and end up in the dog's feces. For some tapeworms, these segments will be white or cream colored and easily visible, and they may move around in the dog's feces. Tapeworm segments may resemble sesame or cucumber seeds in both size and appearance. For other species of tapeworm, these segments may not be visible in the dog's feces.
Dried-out tapeworm segments are hard, specked with yellow and may stick to the dog's fur, explains WebMD. Tapeworm segments may also be visible crawling around a dog's anus or on its bedding. A typical adult tapeworm can measure from 4 to 28 inches long. Tapeworms inhabiting a dog's stomach may make the dog vomit. In this case, tapeworm segments may be visible in the vomit.
A veterinarian determines if a dog has worms by placing its feces under a microscope, explains WebMD. Multiple fecal samples may be necessary to determine a tapeworm infestation because there will not be segments or eggs in every sample.