Psoriasis Australia

Narrowband UVB (NB-UVB)

Narrowband UVB (NB-UVB) phototherapy is one of the most commonly used and effective treatments for moderate to severe psoriasis.

Overview

Narrowband UVB (NB-UVB) phototherapy is one of the most commonly used and effective treatments for moderate to severe psoriasis. This therapy uses a narrow range of ultraviolet B (UVB) light, specifically between 311-313 nanometers. It has largely replaced broadband UVB (BB-UVB) due to its enhanced efficacy, better safety profile, and reduced side effects. NB-UVB is particularly effective for plaque psoriasis but is also used for other forms of psoriasis, including guttate and scalp psoriasis.

Mechanism of Action

NB-UVB phototherapy works by targeting overactive immune cells in the skin that contribute to the rapid turnover of skin cells in psoriasis. The UVB light penetrates the epidermis, the outer layer of the skin, reducing the activity of T-cells and slowing down the abnormal proliferation of keratinocytes (skin cells). This reduces the formation of psoriatic plaques and helps alleviate the associated symptoms such as redness, itching, and scaling.

The narrow spectrum of UVB light (311-313 nm) is particularly effective in targeting these cells while minimizing damage to surrounding healthy tissue. This more precise wavelength reduces the likelihood of burns, skin aging, and other side effects commonly associated with broader-spectrum UV treatments.

Efficacy in Psoriasis Treatment

NB-UVB phototherapy is considered one of the most effective non-systemic treatments for psoriasis. It is particularly useful for patients who do not respond adequately to topical treatments and can be an alternative to systemic drugs like biologics or oral medications.

  1. Improvement in Psoriasis Severity: Studies show that NB-UVB can lead to significant improvements in psoriasis, with 70-90% of patients experiencing clearance or marked reduction in their plaques after 20-30 treatment sessions.

  2. Treatment of Various Psoriasis Types:

    • Plaque Psoriasis: The most common form of psoriasis, plaque psoriasis, responds particularly well to NB-UVB. Large-scale clinical studies have demonstrated that NB-UVB can lead to significant plaque clearance and long periods of remission.
    • Guttate Psoriasis: This form of psoriasis, characterized by small, drop-like lesions, often occurs after a streptococcal infection and can be effectively treated with NB-UVB.
    • Scalp Psoriasis: NB-UVB can be used with specialized equipment (such as scalp applicators) to treat scalp psoriasis, which is difficult to reach with topical treatments.

  3. Remission and Long-Term Control: NB-UVB treatment has been shown to result in remission periods that can last for several months. Some patients may achieve near-complete or complete clearance of their symptoms, while others may require maintenance therapy to prolong remission.

  4. Combination Therapy: NB-UVB can be combined with other treatments for enhanced efficacy. For example, it is often used alongside topical agents like corticosteroids, vitamin D analogues, or systemic medications to optimize the therapeutic outcome.

Treatment Process

NB-UVB therapy is generally delivered in a clinical setting, though home phototherapy units are also available for patients with long-term psoriasis who need ongoing treatment.

  1. Session Frequency and Duration: Patients typically undergo phototherapy two to three times per week. The duration of each session starts at a few seconds to minutes and gradually increases over time as the skin builds tolerance to UV light. Most patients undergo treatment for a period of 8 to 12 weeks.

  2. Dosage Adjustments: The dosage of UVB light is carefully calculated based on the patient’s skin type, psoriasis severity, and previous response to treatment. Dermatologists increase the dose incrementally to minimize the risk of burns and maximize treatment efficacy.

  3. Home Phototherapy Units: For patients with chronic psoriasis who may not have easy access to phototherapy clinics, home phototherapy units prescribed by a dermatologist can provide the same narrowband UVB light. However, regular follow-up and monitoring by healthcare providers are essential to ensure safe use.

Advantages of NB-UVB Phototherapy

NB-UVB phototherapy has several advantages over other treatment options for psoriasis:

  1. High Efficacy: NB-UVB has a high success rate, with many patients achieving substantial improvement or complete clearance of their psoriasis. It is particularly effective for extensive psoriasis that affects large areas of the body.

  2. Fewer Side Effects: Compared to broadband UVB and PUVA (Psoralen + UVA), NB-UVB is associated with fewer short-term and long-term side effects. The more targeted wavelength reduces the risk of skin damage such as sunburn and long-term risks like skin cancer.

  3. Safe for Long-Term Use: NB-UVB is safe for prolonged use, making it a good option for patients who require ongoing treatment. The risk of serious complications such as photoaging or carcinogenesis is lower than with other phototherapies, particularly PUVA, which involves the use of a photosensitizing agent.

  4. Convenient for a Range of Patients: NB-UVB is a non-invasive treatment that can be used by patients who are not eligible for systemic treatments (such as pregnant women or those with contraindications to biologic drugs).

Side Effects and Risks

While NB-UVB phototherapy is considered safe, there are some potential side effects and risks, particularly with long-term or frequent use:

  1. Short-Term Side Effects:

    • Erythema (Redness): Some patients may experience mild to moderate redness of the skin, which is similar to sunburn. This is usually temporary and subsides within a few days.
    • Itching and Dryness: Some patients report itching or dry skin after treatment sessions. These symptoms can often be managed with the use of moisturizers or emollients.

  2. Long-Term Risks:

    • Skin Aging: Prolonged exposure to UV light can accelerate skin aging, leading to wrinkles and pigmentation changes. However, the risk is lower with NB-UVB compared to PUVA or broadband UVB.
    • Skin Cancer: Although the risk is significantly lower than with PUVA, there is still a theoretical risk of skin cancer with long-term or frequent UV exposure. Regular monitoring by a dermatologist is essential to mitigate this risk.

  3. Photosensitivity: Patients with photosensitive skin conditions, such as lupus or xeroderma pigmentosum, may not be suitable candidates for NB-UVB therapy. Special precautions are also necessary for those taking photosensitizing medications.

NB-UVB Phototherapy in Australia

In Australia, NB-UVB phototherapy is widely available at hospitals, dermatology clinics, and some large medical practices. Phototherapy units are typically found in major cities and regional centers, although access may be limited in more rural or remote areas. For patients unable to regularly attend clinic sessions, home phototherapy units may be prescribed.

The Medicare Benefits Schedule (MBS) provides partial coverage for phototherapy treatments in Australia, though patients may still need to pay some out-of-pocket expenses. The availability of NB-UVB therapy in public and private healthcare settings makes it a feasible option for many Australians with moderate to severe psoriasis.

Conclusion

Narrowband UVB (NB-UVB) phototherapy is one of the safest and most effective treatment options for moderate to severe psoriasis. It offers high rates of clearance with minimal side effects and is widely accessible in Australia. While it requires multiple sessions over several weeks, the long-term benefits, including extended periods of remission, make NB-UVB a cornerstone of psoriasis management. Patients should undergo NB-UVB therapy under the supervision of a qualified healthcare provider to ensure the best possible outcomes.