Does Radiation Therapy Cause Hair Loss?

Will Radiation Therapy Cause Hair Loss?

Unfortunately, hair loss is a fairly common side effect with radiation. But as with any medication, dosage is an important part of radiotherapy and its side effects.

Radiation doses are measured in units called gray (Gy), which, to get a little techy, is defined as the absorption of one joule of radiation energy per kilogram of matter.

You might, for example, receive 2 grays of radiation at each treatment, totally 50 grays of radiation over 5 weeks.

Between 75% and 100% of patients who receive cranial radiation doses above 2 grays end up with some amount of hair loss.

But unlike chemotherapy, the alopecia is localised. You’ll only lose hair at the site that received radiation.

With chemotherapy, patients tend to experience diffuse hair loss all over. With radiation, only the site that is treated is impacted. So for example, if you’re receiving radiation therapy on your arm, you may lose some arm hairs but you’ll keep the hair on your head.

Hair loss can also occur where the radiation beam exits your body. So if you’re receiving radiotherapy on one side of your head, you may experience some hair loss where the beam exits on the other side of your head.

How Soon Will I Lose My Hair?

In 1957, two scientists studying the effects of x-rays on hair noticed that the scalp hair roots changed as early as 4 days after exposure to radiation.

Four days sounds quick but the hair loss doesn’t become noticeable until a few weeks later — the general consensus is that you’ll start to notice hair thinning or hair loss 2–4 weeks after your first radiotherapy session.

How Much Hair Will I Lose?

How much hair you lose from radiation depends on three things:

• The size of the area receiving radiation therapy
• The radiation dose
• The type of radiation therapy you receive.

According to a 2020 study, higher doses and proton radiation (rather than photon radiation) generally result in more severe hair loss.

Is Hair Loss from Radiation Permanent?

When radiation impacts anagen hairs (more on that below), the result is a type of hair loss called anagen effluvium.

The good news is that this is typically a temporary condition — most of the time, your hair will regrow within 2–4 months. although it may take longer. Your hair regrowth may also be thinner, curlier, or a different shade than it was before.

Yet about 60% of cranial radiotherapy patients end up with persistent radiation-induced alopecia (pRIA). This is where their hair hasn’t completely regrown 6 months after they’ve finished their radiation therapy.

There may be treatments for pRIA but things get a little trickier if you develop cicatricial (or scarring) hair loss.

This is when radiation-induced hair loss can become permanent because the skin is so scarred that the hair follicles are irreversibly damaged. Rest assured, it’s not a common side effect of radiation therapy.

So What Radiation Dose Causes Permanent Hair Loss?

Every person is different but doses of 7–8 grays of radiation are generally high enough to destroy hair follicles and cause some amount of permanent hair loss.

If you’re concerned, talk to your doctor or care team about your treatment plan. They’ll be able to set your expectations about your hair loss based on the dosage you receive.

Why Does Radiation Cause Hair Loss?

In 1957, scientists noticed that 4 days after radiation exposure, the diameter of the hair bulb shrank until it atrophied — and that this only happened with anagen hairs.

Yep, turns out there’s a link between the hair growth cycle and radiation hair loss:

Hair follicles in the anagen (or growth) stage are more ‘radiosensitive’ than hair follicles in the telogen (or resting) phase. 

Why?

Because radiation destroys fast-growing cells. That’s why it’s so good at killing or stalling cancerous cells. But healthy cells can also get caught up in the process.

Here’s the thing:

The most at-risk cells are those that grow at a fast rate.

And what’s one of the fastest replicating cells in the human body?

Anagen hair cells.

Radiation can impact the hair follicles by producing abnormal cells, impairing metabolic processes, slowing down the hair growth rates, and ultimately causing hair loss.

How to Prepare & Care for Radiation Hair Loss

Scientists have made strides in radiation therapy. These days, they can conform the radiation to the shape of the malignant mass, targeting the cancerous cells while reducing the impact on the healthy tissue around it.

Pretty impressive, huh?

Even so, there’s still a high risk of some degree of hair loss. And that’s not always an easy prospect to deal with.

Below, we cover ways to make the hair loss journey a little gentler.

Be Kind to Yourself

Hair loss is never easy to come to terms with. Plenty of studies acknowledge the profound impact that radiation-induced hair loss can have on self-esteem, self-confidence, and quality of life.

There’s no right or wrong way to respond when you’re dealing with hair loss. Every emotion is valid.

If you need external support, Look Good Feel Better is a program that helps cancer patients manage the physical, psychological, and social impacts of cancer treatment.

Be Kind to Your Hair

Your scalp and hair will be particularly vulnerable during and after treatment. Here are a few things you can do — and avoid — to protect them:

Some things to try:

• Use mild, pH-balanced shampoos or baby shampoos.
• Use soft-bristle brushes and brush from the tips first.
• Pat your hair dry rather than roughly towelling it.
• Sleep with silk or satin pillowcases — they’re smooth enough to prevent tangling or friction.
• Don a hat, headscarf, or wig to protect your scalp from sun and cold exposure.

Some things to avoid:

• Heat — that includes hair dryers, straighteners, or curling wands
• Chemicals like hair sprays, bleaches, or hair dyes
• Anything that may pull on your hair, including hairstyles like braids and cornrows or accessories like bobby pins and hair ties

Some patients who experience hair loss find that cutting the hair short or even shaving their head helps decrease the impact of the hair loss and gives them a sense of control.

Is There a Treatment to Reverse Radiation-Induced Alopecia?

Depending on the severity of your radiation-induced hair loss, you may be able to reverse the effects.

As we’ve discussed above, it all depends on whether you experience temporary anagen effluvium, persistent radiation-induced alopecia (pRIA), or permanent cicatricial (scarring) alopecia.

Anagen effluvium is generally temporary — your hair will usually regrow naturally within 2–4 months.

If you have pRIA, you may be able to stimulate hair follicles to start regrowing with a hair loss treatment.

Most of the time, topical minoxidil is cited as a possible treatment for pRIA. This is generally thanks to a 2020 retrospective study, where 82% of patients with pRIA who were treated with topical minoxidil reported improvements.

The researchers have called for further clinical trials into the possibility of minoxidil as an effective treatment for persistent radiotherapy-induced alopecia.

If you have radiation-induced cicatricial alopecia, the most effective treatment is hair transplantation.

Is It Time to Talk to a Doctor About Your Hair Loss?

There can be some comfort in knowing that your radiation-induced hair loss may be temporary and that within a year — or even 6 months — your hair growth cycle may be back on track.

Feeling a little impatient?

It can help to speak to a doctor who specialises in hair loss.

The Hairy Pill^® offers personalised hair loss treatments for men, as well as women’s hair loss treatments.

However, the treatment is underpinned by regular consultations with doctors who work under the guidance of world-renowned dermatologist Professor Rodney Sinclair.

If you’d like to know if The Hairy Pill^® treatment may work for you, contact us today to talk to a doctor about your options.