The Complex Relationship Between Sunlight and Skin Diseases

Sunlight is an indispensable natural source of life. However, when it comes to certain skin conditions, exposure to sunlight carries both potential benefits and risks. One of the most frequently asked questions by vitiligo patients is: Does sun exposure increase vitiligo spots? To answer this, we must examine the disease’s mechanisms, the condition of the lesions, and the impact of UV rays from a multi-dimensional perspective.

What Is Sunlight and How Does It Affect the Skin?

Sunlight consists of various wavelengths, including UVA, UVB, and UVC rays. These rays can:

• Stimulate melanin production (tanning)
• Trigger vitamin D synthesis
• Have anti-inflammatory effects

But at the same time, they may cause:

• Skin burns
• DNA damage
• Photoaging
• Oxidative stress

Melanin Loss in Vitiligo and the Role of the Sun

In vitiligo patients, melanocyte cells are either destroyed or rendered nonfunctional. As a result, melanin production in the affected areas is absent. This leads to:

• Total vulnerability to sunlight in these spots
• Increased sensitivity to sunburn
• Higher susceptibility to damage compared to healthy skin

So, Does the Sun Increase Vitiligo Spots?

Sunlight does not directly increase vitiligo lesions
It does not cause or directly trigger vitiligo. However, indirect effects can make the spots more visible.

Sunburn may trigger new lesion formation
This is due to the “Koebner phenomenon,” a common condition in vitiligo where skin trauma can result in new spots. Sunburn is one such trauma.

Increased contrast makes the spots more noticeable
While normal skin tans under sunlight, vitiligo-affected areas do not. This intensifies the contrast, making spots more visible.

Possible Effects of Sunlight on Vitiligo

Things to Consider Before Sun Exposure

Vitiligo patients do not need to avoid sunlight entirely. With conscious and protective measures, it is possible to benefit from sun exposure.

1. Use of Sunscreen

• Minimum SPF 50+ protection
• Broad-spectrum (UVA + UVB) coverage
• Fragrance-free, suitable for sensitive skin
• Should be reapplied every 2–3 hours

2. Timing of Sun Exposure

• Avoid direct exposure during peak sunlight hours (11:00 AM–4:00 PM)
• Prefer early morning or late afternoon for brief exposure

3. Protective Clothing and Accessories

• UV-filtering hats and sunglasses
• Long-sleeved cotton clothing
• Cover all areas exposed to UV rays

4. Moisturizer Use

• After sun exposure, skin dryness may increase
• Use natural ingredient-based moisturizers to maintain hydration

Controlled Sun Exposure: Similarity with Phototherapy

Narrowband UVB phototherapy, used in the treatment of vitiligo, is essentially the controlled application of UV light to the skin. This treatment:

• Suppresses overactive immune cells
• Stimulates melanocyte activity and promotes repigmentation
• When administered under dermatologist supervision, controlled UV exposure can support recovery

Common Myths About Sun Exposure and Vitiligo