A brief history of light therapy

Light therapy has been used to treat medical conditions for over 3,500 years. For example, ancient Egyptians and Indians used sunlight to treat vitiligo and other skin conditions.

Niels Ryberg Finsen invented modern phototherapy. Finsen used ultraviolet light and sunlight to treat lupus vulgaris. Lupus vulgaris is tuberculosis that affects the skin (1). The use of light therapy has grown since then. Phototherapy is widely accepted today.

Skin conditions

Light therapy can be used to treat several skin conditions, such as:

· Psoriasis

· Eczema

· Vitiligo

· Itchy skin

· Cutaneous T-cell lymphoma

Treatment of these skin conditions involves using ultraviolet light to slow the growth of skin cells and inflammation. Inflammation is how the human body responds to injuries, infections, and foreign invaders.

UVB rays affect the skin’s outermost layers. On the other hand, UVA rays are less intense but penetrate more deeply into the skin. Both types of UV light can be used in different ways.

Three primary types of light therapy are used for the treatment of skin disorders (2):

· Broadband UVB: This type of light therapy uses a wide range of UVB rays. Sunlight emits UVB rays, but they can’t be seen with naked eyes.

· Narrowband UVB: In this type of therapy, a more intense part of the UVB is used to treat the condition. It is the most typical type of light therapy in use presently.

· PUVA: PUVA is known in full as Psoralen ultraviolet — A. it is a combination of UVA light with psoralen, a chemical obtained from plants. Psoralen can either be applied to the skin or taken as a pill. It increases the sensitivity of your skin to light. The side effects of PUVA are more than some other light therapies. It is the last option (used when other options have failed).

Light therapy for skin disorders has temporary effects. Therefore, you may need more than a session for the best results.

Seasonal affective disorder

Seasonal affective disorder, abbreviated SAD, is a kind of depression linked to specific seasons. Most cases of SAD begin in the fall and stay throughout the winter. Light therapy for seasonal affective disorder involves using a lightbox. A lightbox is specially designed to emit a soft, steady light.

This treatment option is recommended because the side effects are usually not severe or permanent. It is also cost-effective compared to other therapies (3).

If you are on an antidepressant, undergoing a light therapy session may help reduce your dosage. But you must consult your healthcare provider before adjusting your antidepressant dose.

Sleep disorders

The human body has an inner biological clock known as the “circadian rhythm.” This clock regulates your sleeping and waking cycles. The issue with the circadian rhythm is that it doesn’t always work the way it should.

However, studies have shown that light therapy is effective against circadian rhythm disorders. An example is the delayed sleep phase syndrome (DSPS). People who have this disorder cannot fall asleep until it’s close to sunrise. Light therapy can adjust to regular sleeping times (4).

Here’s the thing; light therapy for sleep disorders should be timed correctly. This is very important. Your healthcare provider will help you set the right time (based on your symptoms).

Precancers and cancers

Another form of light therapy is used to treat some precancers and cancers. It is known as photodynamic therapy (5). It involves the use of a photosensitizer alongside the light.

Photosensitizers are usually applied to the skin. When the skin is exposed to light, it interacts with the photosensitizer to create a kind of oxygen that kills cancer cells.

Photodynamic therapy is effective against conditions such as:

· Esophageal cancer

· Endobronchial cancer

· Barrett’s esophagus (a precancerous condition usually caused by acid reflux)

Who is not eligible for light therapy?

People with specific health conditions may need to avoid light therapy. If you find yourself in any of the categories listed below, please, consult your healthcare provider before you undergo a light therapy session:

· Lupus

· Liver disease

· A family history of skin cancer

· Pregnant or breastfeeding