Hookworm is an infection caused by a roundworm. These worms can be found in dirt and other materials with stool. You can catch the infection by direct contact with the infected dirt and stool. The worms enter into your skin. They flow through your blood to your lungs and airways. They move up to your throat and are swallowed into your stomach. When this worm lives in your bowels, it lays eggs there. Some eggs are passed out of your body through your stool. Other worms may come back and enter into the skin around your anus. The skin may become red, itchy, and painful.