What is phototherapy?

Phototherapy means “light treatment.” It uses special types of light (usually ultraviolet or UV light) to treat certain skin problems. The light slows down the overactive skin cells, reduces inflammation, and helps the skin heal.

What is Ultraviolet (UV) Light?

Ultraviolet (UV) light is a type of invisible radiation that is part of the electromagnetic spectrum—the same spectrum that includes visible light, radio waves, and X-rays. The sun is the main natural source of UV light that reaches the Earth.

A small amount of UV exposure is actually helpful, as it allows your body to produce vitamin D, which is important for strong bones and overall health. However, too much UV exposure can damage the skin, leading to sunburn, premature aging, and an increased risk of skin cancer.

In medicine, controlled UV light is used in phototherapy to treat certain skin conditions. Unlike uncontrolled sun exposure, your healthcare provider carefully adjusts the strength and duration of UV light exposure to maximize benefits while minimizing risks.

What are the types of Ultraviolet (UV) Light used in medical therapy?

UV light is divided into categories based on wavelength. Each type behaves differently on the skin:

• UVB (Ultraviolet B)

  • Medium wavelength.

  • Reaches the top layer of your skin (epidermis).

  • Helps in treating certain skin conditions.

  • Overexposure → sunburns.

• UVA (Ultraviolet A)

  • Long wavelength.

  • Penetrates into the first two layers of your skin (epidermis and dermis).

  • Used in medical treatments for deeper skin conditions.

  • Overexposure → wrinkles, premature aging, and sunburns.

What are the different Colors of Phototherapy Lights?

Apart from UV light, other light wavelengths are used in medical phototherapy. These are often delivered using LEDs or lasers:

• Blue Light Therapy

  • Emits a cool blue hue.

  • Commonly used for newborn jaundice (e.g., neoBLUE® devices).

  • Also used in dermatology for acne (targets bacteria).

• Red Light Therapy

  • Emits a warm red hue.

  • Often in the form of LEDs or low-level lasers.

  • Used for wrinkles, redness, acne, scars, and wound healing (stimulates collagen and reduces inflammation).

• Green & Yellow Light Therapy (less common, but used in dermatology)

  • Green light → reduces pigmentation and calms skin.

  • Yellow light → improves circulation, reduces redness and swelling.

What skin problems can be treated with phototherapy?

Phototherapy is commonly used for:

• Psoriasis

• Vitiligo (white patches)

• Eczema

• Atopic dermatitis

• Some types of itching and rashes

How does it actually work?

The light penetrates into the skin and changes how the skin cells behave. It can:

• Slow down the rapid growth of cells (in psoriasis)

• Stimulate pigment cells (in vitiligo)

• Reduce inflammation and itching (in eczema and dermatitis)

Treatment Details:

Before the procedure

• You’ll be given protective eyewear (to shield your eyes).

• Your provider may give you extra protection (blankets, shields) for areas not being treated.

• Sunscreen is applied on skin that shouldn’t be exposed.

• Depending on the treatment area, you may need to remove some clothing.

• For UVA + Psoralen therapy, you might take a psoralen pill, apply it topically, or soak in a psoralen bath.

During the procedure

• Your provider makes sure you’re protected (eyewear, shields).

• UVB Therapy: You’ll stand in a booth (like a tanning bed) or have a wand passed over smaller areas.

• UVA Therapy: Similar to UVB, but psoralen is used to make the skin more sensitive.

• Excimer Laser: A focused UV laser is directed only at the affected spots.

• Session times vary:

  • First UVB session → just a few seconds.

  • Later UVB sessions → a few minutes.

  • UVA therapy → can last up to 1 hour.

After the procedure

Your provider will advise you to:

• Apply sunscreen and/or wear protective clothing.

• Use eye protection outdoors.

• Moisturize daily to prevent dryness.

• Avoid sun exposure and tanning beds to lower risk of burns.

Is it painful?

Not at all, the treatment is completely painless. You just stand or sit in a light box or a handheld device is used for small areas.

How many sessions are needed?

Treatment is usually done 2–3 times a week for several weeks or months, depending on the condition. Some people see results in a few weeks; for others, it may take longer.

Is it safe?

When done under qualified Dermatologist, phototherapy is safe. Doctors measure the exact dose of light for your skin. Long-term use, however, needs monitoring, as too much UV exposure can increase the risk of skin aging or, rarely, skin cancer.

Who should not get phototherapy?

People with a history of skin cancer, very sensitive skin, or those taking medicines that increase light sensitivity should avoid it. Pregnant women should also consult their doctor before treatment.

How soon will I see results?

Results vary. Some patients notice improvement in 3–4 weeks, while others need longer treatment. Regular sessions and follow-up with your dermatologist are key.

Myths vs Facts About Phototherapy

• Myth : Phototherapy same as sitting in the sun

  Fact: No. While sunlight also has UV rays, phototherapy uses controlled medical light in a clinic. It’s carefully measured to give benefits without the harmful effects of too much sun.

• Myth : It causes skin cancer in everyone.

  Fact: When used in controlled doses under a doctor’s care, phototherapy is generally safe. Risk only increases with very long-term or excessive exposure, which is why regular monitoring is important.

• Myth : Phototherapy cures skin problems permanently.

  Fact: Phototherapy helps control conditions like psoriasis, vitiligo, or eczema, but these are long-term (chronic) conditions. The treatment can improve symptoms and sometimes maintain remission, but it’s not a permanent cure.

• Myth : Phototherapy works instantly.

  Fact: Improvement takes time. Most people need multiple sessions over weeks before they notice visible results. Patience is key.

• Myth : Only fair-skinned people can take phototherapy.

  Fact: Phototherapy can be used safely on all skin types. The doctor simply adjusts the dose based on your skin tone and condition.

• In short:

  Phototherapy is a safe, effective, and painless medical light treatment for skin problems when done under qualified dermatologist. It’s not a quick fix, but with consistency and proper supervision, it can make a big difference.

Disclaimer: This article is only for general patient information and is not intended for self medication. There is no legal liability of IADVL arising out of any adverse consequence to the patient. Subsequent to its use for self treatment of the disease images adjust for the depiction of the condition and is not to be used for any other purpose.