What is light therapy?
Ultraviolet (UV) light therapy – also known as phototherapy – is carried out using a machine that produces carefully controlled levels of artificial UV light. These machines aren’t the same as sunbeds – the type of
UV light and the intensity are very different. Light therapy is usually done in a hospital or clinic.
A trained health professional will shine this light on either your whole body, or on an area of skin that needs treatment.
What conditions can light therapy be used for?
Light therapy can help with skin conditions where your skin is inflamed, like psoriasis, eczema, or vitiligo (when patches of your skin lose their colour). Ultraviolet light reduces your body’s immune response and the inflammation in your skin.
Light therapy may help ease itchy skin from eczema, too. It’s not a permanent cure for skin conditions, but it aims to reduce the symptoms.
If you have an inflammatory skin condition and standard treatments such as moisturisers and creams don’t help, your GP may refer you to a dermatologist. This is a doctor who specialises in identifying and treating skin conditions, and they’ll assess you to see if light therapy is suitable for you.
What are the different types of light therapy?
Ultraviolet light is made up of different wavelengths. Two forms are used during light therapy – ultraviolet A (UVA) and ultraviolet B (UVB).
- UVA therapy can be used alone, or together with a chemical called psoralen, which causes your skin to become more sensitive to the light. Psoralen with UVA is known as PUVA. You take psoralen before the session as a tablet, soak parts of your body in a psoralen solution, or apply psoralen gel on affected areas.
- UVB therapy is usually narrow-band UVB (using just a small part of the UVB spectrum) rather than broad-band UVB (using the full UVB spectrum). This is because it avoids some of the more harmful wavelengths.
PUVA is a more intense treatment, so your doctor might only recommend it if treatment with UVB hasn't worked for you. But PUVA can be a better option for certain conditions, such as moderate-to-severe eczema on your hands and feet.
Who can have light therapy?
Your dermatologist will discuss the benefits, risks, and alternatives to the procedure, and assess whether light therapy is suitable for you. They may examine you and ask you questions about your medical history, including the following.
- Whether you’re taking any other medicines, including anything you put on your skin.
- If you have any allergies to medicines.
- Whether you have any history of eye conditions, especially cataracts.
- If you have any conditions that affect other organs in your body, such as your kidney or liver.
- If you have allergy to the sun, or if you have lupus.
- If you’re pregnant or trying to get pregnant.
- Your risk of developing skin cancer. Light therapy may not be recommended if you’ve had skin cancer or you have a family history of the disease.
You’ll need to be able to attend regular sessions of phototherapy (usually two to three sessions a week) and be able to stand up by yourself for at least 10 minutes.
The phototherapy nurse will work out the best dose for you to start on. This is mainly based on your skin type and how easily you burn in the sun. They may test small areas of your skin to check your skin’s sensitivity to ultraviolet light. How these patches of skin react will help calculate the right dose for you to start on.
What are the side-effects of light therapy?
Side-effects are the unwanted, but mostly temporary effects, you may get after having the procedure. The following are possible side-effects of light therapy.
- Red skin, similar to mild sunburn.
- Dry and itchy skin.
- A spotty, itchy rash.
- Cold sores (if you get them).
- Feeling sick. This may happen if you take a psoralen tablet before PUVA therapy.
As with natural sunlight, light therapy can increase your risk of skin cancer and premature skin ageing over the long term. There’s more of a clear link of this risk with PUVA therapy. Your dermatologist and phototherapist will do everything they can to minimise your risk of skin cancer. For example, they will:
- use the lowest dose of UVB or PUVA possible to provide a beneficial effect
- keep a record of how much light therapy you’ve had to make sure your exposure remains within safe limits
- if you’ve had a lot of light therapy, monitor you regularly for signs of skin cancer
- give you information about how to protect your skin and reduce your exposure to UV light following treatment
Can phototherapy be done at home?
There are phototherapy units that you can use at home. These are usually used in remote places where people aren’t near a hospital or clinic to have phototherapy.
But it’s best to have treatment at a hospital or clinic because it’s important to accurately measure the dose of UV light you’re exposed to. This will ensure your treatment is safe and lowers the chance of any side-effects.
It’s difficult to monitor the doses of home phototherapy over time, and the types of sunbeds available for home use are very different from those used in clinics or hospitals.