This process narrows the blood vessels in the scalp so that less drugs reach the hair follicles. However, this may not be very useful when chemotherapy drugs stay in the bloodstream for several hours or if the drugs are taken orally. Some cosmetic products are said to help prevent hair lose. Hair loss usually occurs from two to three weeks after chemotherapy or radiation treatment starts. It can start with a gradual loosening of a few hairs and increase in amount or can suddenly occur.
Many patients say it happens overnight.
The amount of hair loss can range from thinning to complete baldness. For patients treated with chemotherapy, the degree of hair loss is dependent upon the drug and dosage used. Your physician or nurse can tell you what hair loss to expect, depending on your individual treatment program. Fortunately, hair can start to grow back during chemo. For patients receiving radiation treatment, however, hair re-growth may not begin until several months after treatment has been completed.