Psoriasis Australia

Broadband UVB (BB-UVB)

Broadband UVB (BB-UVB) phototherapy has been used for decades to treat various skin conditions, including psoriasis. 

Overview

Broadband UVB (BB-UVB) phototherapy has been used for decades to treat various skin conditions, including psoriasis. This type of phototherapy employs a broader spectrum of ultraviolet B (UVB) light, ranging from 290 to 320 nanometers. Despite its historical role in managing psoriasis, BB-UVB has largely been replaced by narrowband UVB (NB-UVB) in clinical practice due to the superior efficacy and safety profile of the latter. However, BB-UVB is still an available option and may be used in some cases, especially in regions where narrowband phototherapy is less accessible.

Mechanism of Action

The primary mechanism through which BB-UVB works in psoriasis treatment involves the suppression of the immune system’s overactive response that leads to the rapid turnover of skin cells. UVB light penetrates the skin and reduces the rate of keratinocyte proliferation, thereby decreasing the thickening and scaling characteristic of psoriatic plaques.

BB-UVB therapy also has anti-inflammatory effects, reducing the activity of inflammatory cytokines that contribute to the symptoms of psoriasis. This leads to a reduction in plaque thickness, scaling, and redness, although BB-UVB’s broad spectrum can sometimes result in more adverse skin reactions compared to NB-UVB.

Efficacy in Psoriasis Treatment

BB-UVB has been proven effective in treating mild to moderate psoriasis. Studies show that it can lead to significant improvement in skin lesions, particularly when combined with other treatments such as topical corticosteroids or systemic therapies. Some key points about BB-UVB efficacy include:

  • Improvement in Psoriasis Severity: While BB-UVB can reduce the severity of psoriasis lesions, it generally requires more sessions compared to NB-UVB to achieve the same results. Patients typically need 20-30 treatments to see substantial improvement.
  • Disease Clearance: Approximately 60-80% of patients treated with BB-UVB experience some level of clearance or improvement of psoriasis, though this is slightly lower than the rates reported for NB-UVB. The remission period after treatment with BB-UVB is also generally shorter.
  • Maintenance Therapy: Regular maintenance therapy may be needed to prevent recurrence. For patients in remission, follow-up treatments every few weeks can help prolong the effects of BB-UVB.

Treatment Process

  • Sessions: Treatment typically involves sessions three to five times per week, with each session lasting between 10 and 20 minutes depending on the severity of the psoriasis and the patient’s skin type.
  • Duration: The average course of BB-UVB therapy lasts 6-12 weeks. Each session begins with a low dose of UVB exposure, gradually increasing based on the patient’s tolerance and response to treatment.
  • Combination with Other Therapies: BB-UVB is often combined with topical agents, such as coal tar or anthralin, to enhance its effectiveness. These combinations can help reduce the overall number of treatment sessions required.

Advantages of BB-UVB

  1. Accessibility: BB-UVB units are more widely available in some regions than NB-UVB units. For patients in rural or remote areas where narrowband machines may not be accessible, BB-UVB may be the preferred option.
  2. Established Track Record: BB-UVB has been used for decades and is a well-studied and established treatment modality, especially for patients with moderate plaque psoriasis.
  3. Cost-Effective: In some healthcare settings, BB-UVB therapy can be more affordable than narrowband treatments, especially when available in general dermatology practices.

Limitations and Risks

While BB-UVB is effective for treating psoriasis, it has several limitations compared to newer phototherapy options:

  1. Increased Risk of Side Effects: Due to the broader spectrum of light, BB-UVB carries a higher risk of acute skin reactions, such as erythema (sunburn), blistering, and increased pigmentation. These reactions can be more severe than those seen with NB-UVB, particularly in patients with fair skin.

  2. Lower Efficacy: BB-UVB is less effective than NB-UVB, which is why narrowband has become the preferred option in many dermatology clinics. Patients undergoing BB-UVB treatment may require more sessions to achieve the same degree of improvement.

  3. Potential Long-Term Risks: Long-term BB-UVB treatment, like all phototherapy, increases the risk of photoaging and skin cancer, particularly in fair-skinned individuals. This risk is generally greater with BB-UVB than NB-UVB due to the broader range of wavelengths.

  4. Remission Period: While BB-UVB can clear psoriasis, the remission period is often shorter compared to NB-UVB. Patients may experience flare-ups more quickly after the completion of BB-UVB treatment.

Considerations for Use

In Australia, BB-UVB phototherapy remains available but is increasingly being replaced by NB-UVB. Major hospitals and dermatology centers in urban areas typically offer narrowband treatment as the first choice for phototherapy. However, BB-UVB may still be used in areas where access to narrowband phototherapy units is limited. Given the high levels of sun exposure in Australia, dermatologists closely monitor patients undergoing any form of UV phototherapy to minimize the cumulative effects of UV radiation.

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Broadband UVB (BB-UVB) phototherapy remains a viable option for treating psoriasis, particularly in cases where narrowband UVB may not be accessible. While it is less effective than NB-UVB and carries a higher risk of side effects, BB-UVB can still offer significant improvement in psoriasis symptoms for many patients. As with all forms of phototherapy, treatment with BB-UVB should be supervised by a dermatologist to ensure safe and effective outcomes.