Hair loss
Many patients receiving chemotherapy experience hair loss. This is often the most disturbing part of treatment for young people. Hair may fall out suddenly or over a period of weeks or months. It may grow back while the patient is still receiving therapy, but does not usually return to normal until chemotherapy is finished. Radiation therapy may result in permanent hair loss at the site of radiation. The young person may wear a wig, hat, or scarf to hide the loss. Any of these physical changes can result in fear of or actual teasing and rejection by peers. This can create a reluctance to resume friendships and to return to school.

Hematology
A science that studies the formation and diseases of blood.

Hematuria
Blood in the urine.

Hemoglobin (Hgb)
Hemoglobin is a protein substance found in red blood cells. It is composed of iron, which is an oxygen carrier. Abnormally high hemoglobin levels may be seen as a result of hemoconcentration. This may be caused by dehydration. Low hemoglobin values are related to various clinical problems such as anaemia, iron deficiency, severe hemorrhage, chemotherapy treatment and leukemia. Read more

Heratocrit
The percentage of red blood cells in the body. A low hematocrit is suggestive of anemia.

Herpes simplex
The most common virus that causes sores often seen around the mouth (cold sores).

Herpes zoster (Shingles)
Eruption of acute, inflammatory herpectic vesicles on the body following the distribution of peripheral nerves. Seen only in people who previously had chicken pox and often reactivated by stress or an altered immune system.

*HICKMAN™ Catheter
See *BROVIAC™ catheter.
*NOTE: BROVIAC™ catheters and HICKMAN™ catheters are trademarks of C.R. Bard Inc. and its related company, BCR Inc.

Hodgkin disease
Hodgkin disease is a cancer of the lymph nodes. It is the most common form of lymphoma and tends to affect the peripheral lymph nodes such as those in the neck rather than lymph nodes in the trunk. Half of the patients are under the age of 25 at the time of diagnosis. This malignancy reportedly peaks in boys before puberty and in late adolescent girls.