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Symptoms of Blood Disorders

By David J. Kuter, MD, DPhil, Professor of Medicine, Harvard Medical School; Chief of Hematology, Massachusetts General Hospital

Blood disorders can cause various symptoms in almost any area of the body. Most commonly, symptoms are caused by decreases in the blood components.

  • Decreased red blood cells and hemoglobin can cause symptoms of anemia, such as fatigue, weakness, and shortness of breath.

  • Decreased white blood cells or immune system proteins can cause recurrent fever and infections.

  • Decreased platelets or blood clotting factors can cause abnormal bleeding and bruising.

Occasionally, symptoms may relate to increases in blood components.

  • Increased red blood cells can cause headache and a red complexion (plethora).

  • Increased white blood cells or immune system proteins can cause increased blood viscosity (thickening of the blood).

  • Increased platelets or blood clotting factors can cause thrombosis (inappropriate excessive blood clotting).

Some blood disorders cause a person's blood to become thickened by increased quantities of immune-related proteins, red blood cells, white blood cells, or platelets. This thickened (more viscous) blood may have difficulty passing through small blood vessels, decreasing blood flow to certain areas of the body, which is a serious condition called hyperviscosity syndrome. Affected people may experience symptoms such as shortness of breath, headaches, dizziness, and confusion. Hyperviscosity syndrome can occur in people who have multiple myeloma, in which it is caused by increased immune system proteins.

Blood disorders often cause symptoms that can also occur in other disorders. For example, the weakness and shortness of breath caused by anemia can be caused by other conditions that impair oxygen delivery to the body, such as heart or lung disorders. On the other hand, easy bruising, a symptom suggestive of a blood disorder, can be caused by conditions other than a blood disorder, especially disorders of the blood vessels or the use of various drugs such as aspirin.

Disorders other than blood disorders can cause bleeding, but blood disorders often cause very heavy bleeding due to nosebleeds or dental procedures, menstrual bleeding or delivery of a baby, and teething in babies. Blood in the urine or stool is usually not caused by a blood disorder.

Some symptoms are more suggestive of a blood disorder. Just a few examples include the following:

  • Blood clot (phlebitis), usually in a leg (most often causing swelling, redness, and/or warmth of the leg or shortness of breath)

  • Petechiae (a fine pin-point red skin rash) caused by too few platelets

  • Blood blisters in the mouth (caused by too few platelets or clotting problems)

  • Swollen lymph nodes caused by white blood cell cancers (leukemias, lymphomas)

  • Pallor (pale skin) caused by anemia

  • Pica (eating of ice, dirt, or clay) suggests iron deficiency anemia

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