Hair loss is a common side effects of some cancer treatments.
It's a common side effect of some chemotherapy drugs. Hormone therapy and targeted drugs are more likely to cause hair thinning, although some people might have hair loss.
Radiotherapy makes the hair fall out in the treatment area. Hair on other parts of the body is not usually affected.
Whether you lose your hair depends on:
- the type of drug or combination of drugs you are taking
- the dose
- your individual sensitivity to the drug
- your drug treatment in the past
These drugs can cause:
- mild thinning of your hair
- partial hair loss, or loss of patches of hair
- complete hair loss (alopecia)
Complete hair loss can happen gradually. Or hair may fall out fairly quickly, in clumps.
You might also have thinning or loss of eyelashes, eyebrows and other body hair. For example, pubic hair, underarm hair and chest hair in men.
Chemotherapy drugs work by killing growing cells such as cancer cells. But normal body tissues such as the hair follicles, also have lots of growing cells. This is what makes your hair fall out.
Not all chemotherapy drugs cause hair loss. Some don't cause any hair loss at all, or only slight thinning. If your hair is going to fall out, it usually begins within 1 to 3 weeks after treatment starts.
Hair usually grows back once your treatment has finished. However, in some people it may not grow back, or it might grow back patchy. This usually only happens with very high doses of particular drugs.
It might take several months for hair to grow back. It might look the same as before, or it may be thicker or thinner. Sometimes it can be a different colour or curlier.
Targeted cancer drugs
There are different types of targeted drugs and these cause hair problems to different degrees. Some of these drugs cause slower hair growth, hair thinning and dry, brittle hair. Some can cause hair loss on the head and body. It can vary as to when these hair changes start. They can develop between several weeks to 2 to 3 months after starting treatment.
Instead of hair loss, some targeted cancer drugs cause growth of hair in unexpected areas of the body. For example, excessive hair on the face in women. Or some people might develop very long, curly eyelashes.
Talk to your doctor or nurse if your treatment is causing excessive hair growth. Ask about the safest way to remove unwanted hair. For example, you (or someone else) might need to carefully trim your eyelashes every few weeks to stop them irritating your eyes.
Hormone therapies are more likely to cause hair thinning. This usually slows down or stops within the first year of starting treatment.
In some people, it may not thicken until a few weeks after finishing hormone therapy.
Radiotherapy generally causes some hair loss to the part of the body that is being treated. How much hair loss you have depends on the size of the area you have treated and the dose of the radiotherapy.
Radiotherapy to the head always causes some hair loss. Your hair will fall out where the radiotherapy beams enter your head. You can also lose some hair on the opposite side, where the radiotherapy beams pass through.
Hair usually grows back for most people. But some people might have permanent hair loss. This is more likely if you have had higher doses of radiotherapy. Ask your doctor what they think might happen in your situation.
It might take more than 6 months or more after radiotherapy for your hair to grow back. Hair regrowth may be patchy at first, and it might stay patchy for some people.
Reducing hair loss from chemotherapy
Some people want to look into ways of reducing hair loss from their treatment. There is no known way to prevent hair loss from radiotherapy, hormonal therapies or targeted medicines. For chemotherapy, it might be possible to try scalp cooling to reduce hair loss.
Scalp cooling can sometimes reduce the amount of hair loss.
Scalp cooling lowers the temperature of your scalp and reduces the blood flow in the scalp. This reduces the amount of drug reaching the hair follicles on your head. With less of the cancer drugs getting to the hair follicles, the hair is less likely to die off and fall out.
There are different types of scalp cooling, these include the:
- cold cap – a hat filled with gel that is chilled before you put it on
- refrigerated cooling system – you wear a cap that is attached to a machine, the machine pumps liquid coolant into the cap
You can ask your doctor or nurse whether your hospital has scalp cooling and which type they use. They can explain exactly what happens.
When not to use scalp cooling
Scalp cooling is not suitable for use in all types of cancer or situations. You won’t normally have scalp cooling if there is too high a risk that there might be cancer cells in your scalp blood vessels. This is because the cells in the scalp blood vessels might survive the treatment.
So for example, scalp cooling is not recommended in people:
- with cancers such as leukaemia and lymphoma
- whose cancer has spread to the scalp
- who are due to have radiotherapy to their scalp
You would not have scalp cooling with continuous chemotherapy through a pump or with chemotherapy tablets. This is because you would have to wear the cold cap for 24 hours a day.
Some doctors are not happy about their patients using scalp cooling for any type of cancer. They worry about the risk of cancer cells being left in the scalp, leading to cancer spread in the skin of the scalp (scalp metastases).
In theory there is a risk, but there is not enough evidence to know this for sure. Research in this area has mainly looked at women with breast cancer.
A 2017 review of 10 different studies looked at the number of scalp metastases in women who had scalp cooling and women who did not. The number of women affected with scalp metastases in either group was small and there was no significant difference between the 2 groups. Scalp metastases are very rare in women with breast cancer.
Things to think about
Scalp cooling only blocks certain drugs and does not work for everyone. You might still have hair thinning, or lose your hair completely. You can't tell whether it will work for you until you try it.
You spend longer at hospital having your treatment if you have scalp cooling. You need to wear the cap before, during and after you have the chemotherapy drugs into your bloodstream.
The time varies depending on the drug. For example, you might wear the cap:
- about 30 minutes before treatment
- during treatment – this could be anything from 10 minutes to a couple of hours
- following treatment - ranging from 45 minutes to 2 hours to 4 hours
The nurse might ask you to dampen or wet your hair before you put on the cap or cooling system. One study showed that wetting the hair improved contact between the scalp and cap. This reduced the temperature of the skin on the scalp. But research is not definite in this area. It is not possible to say for sure that wetting the hair makes scalp cooling work better.
Research suggests that scalp cooling with Afro Caribbean hair is not as successful. So your nurse might recommend you have longer periods of scalp cooling if this applies to you.
Scalp cooling can make you feel cold all over. And it can make you feel uncomfortable and give you a headache. Take lots of layers to put on and ask for a blanket if you need it. Hot drinks will help you feel warmer.