If you have a hookworm infection, the first symptom you will notice is generally that your skin is itchier than normal. The itching begins with the hookworm larvae enter your skin. You may also notice the skin swelling and becoming red in the area where the itching sensation is the worst. This is also caused by the larvae entering your skin. People commonly feel hookworm itch in their hands and feet. When the hookworm enters your intestines, it can aggravate your intestines, leading to nausea and diarrhea. The hookworm can also release toxins that disrupt your digestive system. The nausea may occur with or without vomiting. Look for blood in your stool. The blood could be red or black. Hookworms can cause your colon to become inflamed. They can also irritate the lining of your intestine, which is comprised of the colon, cecum and rectum. When this occurs you might experience cramps in your abdomen. This symptom only occurs in severe hookworm infections. Hookworms feed directly on their hosts blood, which can lead to their host becoming iron deficient. Signs that you are iron deficient include:  Extreme fatigue and overall weakness. Pale skin and eyes. Chest pain and headache. Shortness of breath.

TL;DR in Vietnamese:
Để ý khi thấy da đột nhiên ngứa và phát ban. Theo dõi chứng buồn nôn và tiêu chảy. Lưu ý hiện tượng chuột rút. Chú ý nếu bạn đột ngột bị thiếu sắt.