Excessive bruising

A random bruise is probably nothing to worry about. However, if you start to notice bruises popping up all the time, especially in places you wouldn’t normally get them, like your hands or fingers, see a doctor. Unusual bruising can be a symptom of leukemia, according to Cancer Treatment Centers of America. Over time, leukemia impairs the blood’s ability to carry oxygen and clot.
Unexplained weight loss

“Weight loss is a good thing—but if you have less appetite when you usually have a good appetite, and there’s no big life event or problems happening to cause that, get it checked out,” says Dr Markman of the American Cancer Society. Losing weight can be a side effect of many different cancers such as oesophageal, pancreatic, liver, and colon, but it’s an especially common symptom of leukemia or lymphoma, says Dr Wender. Unexplained weight gain can signal a big problem too—it’s one of the essential medical facts doctors think you should know.
Persistent fatigue

Everyone has low-energy days. However, if you feel tired every day for more than a month, or experience shortness of breath when you didn’t before, see a doctor, says Dr Wender. Leukemia and lymphoma commonly cause persistent fatigue. “Most of the time it won’t be cancer, but get it checked because you never know,” he says.