What is Light Therapy and How Does It Work in Vitiligo?

Vitiligo is a chronic skin condition characterized by the destruction of melanocytes—the cells responsible for producing skin pigment. The loss of these cells leads to the development of white patches on the skin. Light therapy, also known as phototherapy, is a medical treatment that uses controlled ultraviolet (UV) light to stimulate melanocyte activity and potentially restore pigmentation.

Phototherapy primarily works by modulating the skin’s immune response and promoting repigmentation in affected areas. It’s one of the most scientifically supported treatments for vitiligo, especially in non-segmental cases.

Types of Phototherapy Used in Vitiligo

1. Narrowband UVB (NB-UVB)

• Most commonly used and safest method
• Uses UVB light with wavelengths of 311–313 nanometers
• Suitable for widespread vitiligo
• Can be used in both children and adults
• Often considered first-line therapy

2. PUVA Therapy (Psoralen + UVA)

• Combines a photosensitizing drug (psoralen) with UVA light
• Less commonly used today due to higher side effect profile
• May cause nausea, eye sensitivity, and phototoxic reactions
• Reserved for select cases where NB-UVB is not effective

3. Excimer Laser or Excimer Lamp

• Delivers focused 308 nm UVB light to localized lesions
• Ideal for treating small, stable areas like hands or face
• Requires fewer sessions compared to full-body NB-UVB
• Minimal exposure to healthy skin

Step-by-Step Light Therapy Process

Light therapy must be administered under the supervision of a dermatologist. Here’s what the typical treatment protocol looks like:

1. Initial Evaluation

Before starting therapy, the dermatologist assesses:

• Type and extent of vitiligo
• Skin type and sensitivity
• Any previous treatments
• Coexisting skin conditions

2. Determining the Initial Dose

The Minimum Erythema Dose (MED) test is performed to determine the patient’s UV sensitivity. This helps in setting a safe starting dose.

3. Treatment Sessions

• Usually conducted 2–3 times per week
• Sessions begin with short exposure times (30 seconds–1 minute)
• Duration increases gradually, based on patient response
• Results typically begin after 20–30 sessions
• A full course may span 3–6 months

4. Protection Measures

• Eyes are covered with UV-blocking goggles
• Lips, genitals, and unaffected skin may be protected with zinc oxide or physical barriers
• Special care is taken to avoid overexposure

5. Ongoing Monitoring

Progress is monitored every few weeks. Adjustments are made based on:

• Skin reaction
• Pigmentation response
• Any side effects

Who is a Good Candidate for Light Therapy?

Light therapy is effective for:

• Generalized vitiligo affecting large areas
• Recent-onset patches
• Facial and trunk involvement
• Patients who do not respond well to topical treatments
• Children and adults (under medical supervision)

However, it may be less effective on hands, feet, lips, and long-standing lesions.

Benefits of Light Therapy in Vitiligo

• Non-invasive: No needles or surgery
• Well-tolerated: Especially narrowband UVB
• Can be combined with other treatments
• Safe for long-term use
• Boosts confidence: Visible improvements can enhance emotional well-being

Potential Side Effects

While generally safe, some patients may experience:

• Temporary redness or itching
• Dry skin or peeling
• Mild burns (if dosage is too high)
• Long-term use (especially with PUVA) may increase skin aging risk

To minimize these risks, treatments should always be conducted or supervised by professionals.

Home-Based Phototherapy Devices

Portable narrowband UVB units are now available for at-home use. These can be cost-effective and convenient but require:

• A prescription and guidance from a dermatologist
• Training on how to apply and measure doses
• Regular follow-ups to track progress and adjust protocol

Unsupervised use can result in burns or treatment failure.

Effectiveness of Light Therapy

Several studies highlight the success of NB-UVB treatment:

• Face and neck: 60–80% repigmentation
• Trunk: 50–70%
• Limbs: 30–40%
• Hands and feet: Often <30% response rate

Results depend on skin type, area treated, disease duration, and adherence to the treatment schedule.

Post-Treatment Care and Precautions

• Avoid natural sun exposure for several hours after therapy
• Use moisturizers to soothe any dryness or irritation
• Report any new lesions or adverse reactions to your doctor
• Continue routine follow-ups even after pigmentation improves