Light therapy (phototherapy) uses specific wavelengths of light, including lasers and light-emitting diodes (LEDs), to help treat different conditions.
Light therapy seems to signal certain chemicals in the body that are involved in healing processes and mood.
People use light therapy for seasonal depression, yellowing of the skin in infants (neonatal jaundice), psoriasis, eczema, and bipolar disorder. It's also sometimes used for acne, dementia, wound healing, and many other conditions, but there is no good scientific evidence to support many of these other uses.
Is It Effective?
Natural Medicines rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
- Yellowing of the skin in infants (neonatal jaundice). Light therapy is effective for jaundice in infants.
- Scaly, itchy skin (psoriasis). Light therapy with ultraviolet B (UVB), or ultraviolet A (UVA) combined with a drug called psoralen, reduces psoriasis symptoms.
- Seasonal depression (seasonal affective disorder, SAD). Light therapy is effective for SAD. It might be as effective as certain conventional drugs for reducing symptoms. But it's not clear if it helps prevent SAD.
- Eczema (atopic dermatitis). Light therapy with ultraviolet A (UVA) or ultraviolet B (UVB) light can reduce itching, swelling, and other symptoms of eczema.
- A cancer that begins in white blood cells and affects the skin (mycosis fungoides). Light therapy with ultraviolet B (UVB), or ultraviolet A (UVA) combined with a drug called psoralen, can treat a type of cancer called mycosis fungoides.
- Bipolar disorder. Light therapy seems to help treat bipolar depression, especially when used together with conventional drugs.
- An eye disease called choroidal neovascular membranes (CNVM). Light therapy combined with verteporfin might improve vision in people with CNVM.
- Disorders that affect when a person sleeps and when they are awake. Light therapy seems to help improve sleep-wake cycle disturbances.
- Depression. Bright light therapy used alone or together with conventional drugs seems to help improve symptoms of depression.
- Cold sores (herpes labialis). A specific light therapy device seems to make cold sores heal faster.
- Insomnia. Light therapy seems to improve sleep in people with insomnia.
- Itching. Light therapy with ultraviolet B (UVB) light seems to reduce itching in people with kidney failure who are receiving hemodialysis.
- Hardening of skin and connective tissue (scleroderma). Light therapy with ultraviolet A (UVA) improves symptoms of scleroderma. But it's not as effective as treatment with methotrexate.
- A skin disorder that causes white patches to develop on the skin (vitiligo). Light therapy seems to improve skin discoloration by a small amount in people with vitiligo. Light therapy used with other treatments, such as lactic acid, seems to work better for vitiligo than either treatment alone.
There is interest in using light therapy for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Is it Safe?
Light therapy is likely safe when used on the skin short-term and under the supervision of a healthcare professional. The most common side effects are skin redness, itching, and burning.
Light therapy with ultraviolet A (UVA) or ultraviolet B (UVB) is possibly safe when used long-term. There's been concern that using these therapies long-term might increase the risk for skin cancer, but that doesn't seem to be the case.
Combining UVA light therapy with a drug called psoralen (PUVA) is possibly unsafe when used long-term. Using PUVA long-term can increase the risk for a certain type of skin cancer, called squamous cell carcinoma.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Bright light therapy is possibly safe when used short-term while pregnant. It's not clear if other types of light therapies are safe to use while pregnant or breast-feeding. Stay on the safe side and avoid use.
Children: Light therapy is possibly safe in infants when used appropriately under the supervision of a healthcare professional.
Skin conditions: Light therapy given for certain skin conditions can cause a type of rash called polymorphic light eruption. People with hardening of skin and connective tissue (scleroderma), a type of non-cancerous skin sore (granuloma annulare), or a skin condition that causes small, scaling, raised spots (pityriasis lichenoides chronica or PLC) are at greatest risk for this rash.
Medications that increase sensitivity to sunlight (Photosensitizing drugs)
Interaction Rating=Moderate Be cautious with this combination.
Some medications might make the skin more sensitive to sunlight. Using light therapy with these medications might increase the risk of blistering, rashes, or other side effects.
Herbs that might increase sensitivity to sunlight: Using light therapy along with herbs that can increase sensitivity to light can increase the risk of rashes and other side effects. Examples of supplements with this effect include bishop's weed, chlorophyll, khella, and St. John's wort.
There are no known interactions with foods.
There are many different types of light therapy using many different sources of light. These include blue and special blue fluorescent tubes, halogen, fiber-optic, and light-emitting diodes (LEDs). Light can be delivered to the entire body or to a specific area. Light boxes with high-intensity florescent lights are often used for mood and sleep disorders. Treatments may be administered by a healthcare professional. There are also at-home devices available. Be sure to seek and follow relevant directions from your physician or other healthcare professional before using this therapy.
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