Understanding Phototherapy in Dermatology: Treating Psoriasis Eczema and Other Inflammatory Skin Diseases Safely
Phototherapy has become a valuable tool in dermatology, offering relief for many chronic skin conditions. For people struggling with psoriasis and eczema, phototherapy provides an alternative when topical treatments or medications fall short. This treatment uses specific types of light to reduce inflammation, slow skin cell growth, and improve overall skin health. Understanding how phototherapy works, the conditions it treats, the typical treatment process, and safety considerations can help patients make informed decisions about their care.
Skin Conditions Treated with Phototherapy
Phototherapy is effective for several skin disorders, especially those involving inflammation or abnormal skin cell growth. Here are the most common conditions treated:
Psoriasis
Psoriasis causes red, scaly patches on the skin due to rapid skin cell production. Phototherapy slows down this process and reduces inflammation. Narrowband UVB (a small number of wavelengths of ultraviolet B) treatment is commonly used, with PUVA (psoralen plus UVA (ultraviolet A)) used less often. Narrowband UVB is often preferred because it has fewer side effects and does not require medication before exposure.
Eczema (Atopic Dermatitis)
Eczema leads to dry, itchy, and inflamed skin. Phototherapy helps by calming the immune response and improving skin barrier function. Narrowband UVB is the most common light used for eczema, providing relief from itching and reducing flare-ups.
Other conditions that may benefit from phototherapy include pruritus (itching), vitiligo, lichen planus, and cutaneous T-cell lymphoma, but psoriasis and eczema remain the most frequent uses.
How Phototherapy Works and Types of Light Used
Phototherapy uses specific wavelengths of light to affect the skin in therapeutic ways. The main types of light used include:
Narrowband UVB (311-313 nm): This is the most common and safest form of phototherapy. It penetrates the skin to slow down cell growth and reduce inflammation whilst minimising significant damage.
Broadband UVB: An older form of UVB therapy that covers a wider range of wavelengths but is less targeted and has more side effects.
PUVA (Psoralen + UVA): This combines a light-sensitizing drug (psoralen) with UVA light. Psoralen makes the skin more responsive to UVA, increasing effectiveness but also raising the risk of side effects.
The light penetrates the skin and interacts with immune cells and skin cells. In psoriasis and eczema, it reduces the overactive immune response and slows skin cell production.
Typical Number of Sessions for Effective Treatment
The number of phototherapy sessions varies depending on the condition, severity, and individual response. Treatment usually occurs in a clinical setting under professional supervision.
In posoriasis patients often start with 2-3 sessions per week. Improvement may be seen after 6-8 weeks, with a typical course lasting 20-30 sessions. Maintenance treatments may be needed to prevent relapse. However, longer treatment courses may be needs, e.g. in vitiligo to get repigmentation.
Each session usually lasts a few seconds to a few minutes, depending on the light type and skin sensitivity. Dermatologists adjust the dose carefully to balance effectiveness and safety.
Potential Side Effects and Safety Considerations
Phototherapy is generally safe when administered by trained professionals, but it carries some risks and side effects:
Skin redness and irritation: Mild sunburn-like symptoms can occur, especially if the dose is too high.
Dry skin: Patients may experience dryness or peeling during treatment.
Itching: Some people report itching after sessions.
Increased risk of skin aging: Long-term UV exposure can accelerate skin aging.
Skin cancer risk: PUVA therapy carries a higher risk of skin cancer with prolonged use. Narrowband UVB has a lower risk but still requires monitoring.
Eye protection: Patients must wear goggles during treatment to protect their eyes from UV damage.
Patients should inform their dermatologist about any medications or conditions that increase photosensitivity. Regular skin checks are important to monitor for any adverse effects.
Practical Tips for Patients Considering Phototherapy
Discuss your full medical history with your dermatologist.
Follow the treatment schedule closely for best results.
Use moisturisers to combat dryness.
Protect your eyes during sessions.
Report any unusual skin changes immediately.
Understand that phototherapy is part of a broader treatment plan, often combined with topical or systemic therapies.
Phototherapy offers a targeted, effective option for managing difficult skin conditions. With proper care and supervision, it can improve quality of life and skin health for many patients.
