Psoriasis Australia

Coal Tar

Coal tar is a thick, black liquid byproduct derived from the distillation of coal. It has been used for over a century in dermatology to treat various skin conditions, including psoriasis.

Overview of Coal tar

Coal tar is effective in reducing scaling, itching, and inflammation associated with psoriasis. Despite its long history of use, the exact mechanisms by which coal tar exerts its therapeutic effects are not fully understood. However, it remains a popular treatment due to its affordability and effectiveness, particularly for mild to moderate psoriasis.

How Coal Tar Works

While the precise mechanism of action of coal tar is not completely understood, it is believed to work in several ways to alleviate the symptoms of psoriasis:

  1. Antiproliferative Effects: Coal tar slows down the rapid growth of skin cells (keratinocytes), which is a hallmark of psoriasis. This helps reduce the thickness of plaques.

  2. Anti-Inflammatory Properties: Coal tar contains phenols and other compounds that have anti-inflammatory effects, helping to reduce redness and swelling in psoriatic lesions.

  3. Antipruritic (Anti-Itch) Properties: Coal tar is also known to relieve itching, which is a common and distressing symptom of psoriasis.

  4. Keratolytic Action: Coal tar helps to soften and shed the thick scales associated with psoriasis, leading to smoother skin.

Forms of Coal Tar

Coal tar is available in various formulations, each tailored to different types of psoriasis and areas of the body:

  • Creams and Ointments: These are commonly used for treating plaque psoriasis on the body. Ointments, being more occlusive, are particularly useful for dry, scaly plaques.

  • Shampoos: Coal tar shampoos are widely used to treat scalp psoriasis. They help to reduce scaling and itching on the scalp.

  • Bath Additives: Coal tar can also be used as a bath solution, allowing for widespread treatment of psoriasis across the body.

  • Lotions and Gels: These lighter formulations are easier to apply and are often used for less severe psoriasis or in combination with other treatments.

Usage Guidelines

When using coal tar for psoriasis, it’s important to follow proper guidelines to maximize benefits and minimize side effects:

  • Application Frequency: Coal tar products are typically applied once or twice daily, depending on the severity of the psoriasis and the product formulation.

  • Duration: Coal tar can be used for extended periods, but it’s often recommended to monitor its use under the guidance of a healthcare provider due to potential side effects.

  • Scalp Psoriasis: When using coal tar shampoo, it’s usually advised to leave the shampoo on the scalp for a few minutes before rinsing to enhance effectiveness.

  • Avoid Sun Exposure: Coal tar can increase the skin’s sensitivity to sunlight, so it’s important to avoid prolonged sun exposure or use sunscreen when going outdoors after applying coal tar products.

Benefits of Coal Tar

Coal tar remains a favored treatment for psoriasis due to several benefits:

  1. Cost-Effective: Coal tar is relatively inexpensive compared to newer psoriasis treatments, making it an accessible option for many patients.

  2. Long History of Use: With over a century of clinical use, coal tar has a well-documented safety profile when used correctly.

  3. Combination Therapy: Coal tar is often used in combination with other treatments, such as topical corticosteroids or phototherapy, to enhance treatment outcomes.

  4. Versatility: Available in multiple formulations, coal tar can be adapted to different types of psoriasis and patient preferences.

Potential Side Effects

While coal tar is generally safe, it can cause side effects, especially with prolonged use:

  1. Skin Irritation: Some patients may experience redness, burning, or stinging upon application. This is more common with higher concentrations of coal tar.

  2. Photosensitivity: Coal tar increases the skin’s sensitivity to ultraviolet (UV) light, which can lead to sunburn. It’s advisable to avoid sun exposure or use adequate sun protection.

  3. Staining and Odor: Coal tar products can stain clothing, bedding, and skin. They also have a strong, distinctive odor that some patients find unpleasant.

  4. Carcinogenic Concerns: There have been concerns about the potential carcinogenicity of coal tar, especially with long-term use. However, studies have shown that when used appropriately, the risk is minimal. The U.S. Food and Drug Administration (FDA) has classified coal tar as a Category I ingredient for the treatment of psoriasis, indicating it is generally recognized as safe and effective .

Scientific Evidence Supporting Coal Tar Use

Several studies have supported the efficacy and safety of coal tar in treating psoriasis:

    1. Clinical Studies: Research has shown that coal tar is effective in reducing the severity of psoriasis symptoms. A study published in the Journal of the American Academy of Dermatology found that coal tar was comparable in efficacy to other topical treatments like corticosteroids when used for mild to moderate psoriasis .

    2. Combination with Phototherapy: Coal tar is often used in combination with ultraviolet B (UVB) phototherapy in a regimen known as the Goeckerman regimen. This combination has been shown to be highly effective in treating psoriasis, with studies indicating significant improvement in patients undergoing this treatment .

    3. Long-Term Safety: A review published in Dermatologic Therapy highlighted that while coal tar has been used for over a century, concerns about its carcinogenicity have not been substantiated by clinical evidence. The review concluded that coal tar remains a safe and effective option for long-term management of psoriasis .

Special Considerations

  • Children: Coal tar can be used in children, but it is typically recommended in lower concentrations and for limited periods. Pediatric use should always be guided by a healthcare provider.

  • Pregnancy and Breastfeeding: The use of coal tar during pregnancy and breastfeeding should be discussed with a healthcare provider. Although generally considered safe, alternative treatments may be preferred during these periods.

Accessing Coal Tar in Australia

In Australia, coal tar products are available over the counter and by prescription, depending on the concentration and formulation. They are widely accessible in pharmacies and can be an effective and affordable treatment option for managing psoriasis.

Summary

Coal tar remains a valuable option in the treatment of psoriasis, particularly for patients seeking a cost-effective and well-established therapy. Its use is supported by a long history of clinical experience and scientific research, making it a reliable choice for many patients. However, like all treatments, it should be used under the guidance of a healthcare provider to ensure optimal results and minimize risks.