Coal Tar: From Traditional to Modern Psoriasis Treatment

Introduction

Few skincare ingredients have a history as rich and enduring as coal tar. Long before biologics and sophisticated immunomodulators entered the scene, this dark, distinctive-smelling substance served as one of medicine's most reliable weapons against psoriasis and other inflammatory skin conditions. Derived from the distillation of coal, this complex mixture of hydrocarbons has been used by dermatologists for over a century, earning its place as one of the oldest continuously used treatments in modern medicine. While newer, more cosmetically elegant options have emerged in recent decades, coal tar maintains its significance in dermatology—not as a relic of the past, but as an effective, affordable option with unique properties that continue to benefit patients today. For those struggling with stubborn psoriasis plaques, persistent scalp flaking, or other inflammatory skin conditions, understanding coal tar's mechanisms, benefits, and proper usage could provide an often-overlooked pathway to relief. Let's explore how this traditional remedy has evolved in modern dermatology and why it remains relevant in an era of cutting-edge skin treatments.

What Is Coal Tar?

Coal tar is a thick, dark brown to black viscous liquid produced as a byproduct during the carbonization of coal to make coke or gas. Chemically, it's an extraordinarily complex mixture containing thousands of compounds, primarily polycyclic aromatic hydrocarbons (PAHs), phenols, heterocyclic compounds, and various aromatic bases and acids. This complexity contributes to both its therapeutic properties and its characteristic strong odor.

In its pure form, crude coal tar (pix carbonis) contains approximately 10,000 different compounds and is rarely used directly on the skin. Instead, pharmaceutical preparations utilize refined coal tar extracts or solutions in concentrations typically ranging from 0.5% to 10%, depending on the specific formulation and intended use.

The history of coal tar in medicine dates back to the late 19th century. Its therapeutic properties were first documented in 1877 when Ferdinand von Hebra, considered the father of modern dermatology, reported success using coal tar to treat psoriasis and eczema at the Vienna General Hospital. This discovery emerged during the Industrial Revolution when coal distillation for gas lighting was widespread, making coal tar readily available as an industrial byproduct.

By the early 20th century, coal tar had become a mainstay in dermatological practice, particularly after the development of the Goeckerman regimen in 1925 by Dr. William Goeckerman at the Mayo Clinic. This treatment combined coal tar application with controlled exposure to ultraviolet light, demonstrating remarkable efficacy for severe psoriasis—an approach that remains in use in modified forms today.

Throughout the 20th century, coal tar was incorporated into various formulations, from crude preparations used in hospital settings to more refined products for home use, including shampoos, creams, ointments, and bath additives. The FDA has historically classified coal tar as generally recognized as safe and effective (GRASE) for over-the-counter treatment of psoriasis and seborrheic dermatitis, though regulatory approaches vary globally.

While pharmaceutical innovation has introduced numerous alternative treatments over the decades, coal tar has maintained its place in dermatological practice, valued for its affordability, established safety profile, and effectiveness for conditions that sometimes prove resistant to newer approaches.

Key Benefits of Coal Tar

Powerful Anti-Proliferative Effects for Psoriasis Plaques

Coal tar's most significant benefit is its ability to normalize the accelerated cell turnover characteristic of psoriasis. In healthy skin, epidermal cells typically mature and shed over approximately 28 days, but in psoriatic skin, this process is dramatically accelerated to just 3-4 days, resulting in the thick, scaly plaques that define the condition. Coal tar effectively slows this hyperproliferation, helping restore a more normal cell maturation cycle. Clinical studies demonstrate that coal tar reduces epidermal DNA synthesis by 25-30% within 24 hours of application, directly addressing the pathological cell division that creates psoriatic lesions. This anti-proliferative action translates to visible improvement in plaque thickness, with studies showing an average reduction of 60-70% in scale thickness after 3-4 weeks of consistent use. For patients with chronic plaque psoriasis, particularly those with thick, stubborn lesions on areas like elbows, knees, and scalp, coal tar often succeeds when other topical treatments have failed. Users typically notice initial improvements within 1-2 weeks, with significant clearing possible within 4-8 weeks of regular application. This normalization of cell turnover not only improves appearance but also reduces itching and discomfort, providing both cosmetic and symptomatic relief.

Anti-Inflammatory and Anti-Pruritic Relief

Beyond controlling cell proliferation, coal tar demonstrates remarkable anti-inflammatory properties that help calm the underlying immune dysregulation driving psoriasis and other inflammatory dermatoses. Research indicates that coal tar inhibits key inflammatory pathways, including the production of pro-inflammatory cytokines like interleukin-1, interleukin-6, and tumor necrosis factor-alpha. This immunomodulatory effect helps break the inflammatory cycle that perpetuates psoriatic lesions. Additionally, coal tar possesses significant anti-pruritic (anti-itch) properties, addressing one of the most distressing symptoms of psoriasis and similar conditions. Clinical evaluations show that approximately 70% of patients report substantial itch relief within the first week of treatment, often before visible improvement in lesion appearance. This rapid symptom relief improves quality of life and helps prevent the itch-scratch cycle that can worsen inflammation and potentially trigger new psoriatic lesions through the Koebner phenomenon. For scalp psoriasis, which affects approximately 80% of psoriasis patients at some point, coal tar shampoos often provide more effective itch relief than conventional anti-dandruff products, with studies demonstrating a 60% greater reduction in pruritus scores compared to zinc pyrithione shampoos. This combination of anti-inflammatory and anti-pruritic properties makes coal tar particularly valuable for patients whose primary concern is physical discomfort alongside visible symptoms.

Additional Benefits

Coal tar offers several complementary advantages that enhance its therapeutic value. It demonstrates antifungal and antibacterial properties that help address secondary infections that can complicate psoriasis and seborrheic dermatitis. This antimicrobial action is particularly beneficial for intertriginous areas (skin folds) where maceration and microbial overgrowth often exacerbate inflammatory conditions. Coal tar also possesses photosensitizing properties that enhance the skin's responsiveness to natural or therapeutic ultraviolet light—the basis for its historical use in the Goeckerman regimen and a factor that can improve results when combined with controlled sun exposure or phototherapy. From a practical perspective, coal tar represents one of the most cost-effective psoriasis treatments available, with over-the-counter preparations typically costing 70-90% less than prescription alternatives, making it accessible for long-term management of this chronic condition. Unlike some newer psoriasis treatments that lose efficacy over time due to tachyphylaxis (decreased response with continued use), coal tar typically maintains its effectiveness during extended treatment courses. This sustained action makes it valuable for ongoing maintenance therapy to prevent relapse after achieving clearance. Additionally, coal tar has a well-established safety profile for long-term use, with decades of clinical experience showing minimal systemic absorption and rare serious adverse effects when used as directed—an important consideration for a chronic condition requiring indefinite management.

How Coal Tar Works

Coal tar operates through several sophisticated mechanisms that collectively normalize skin cell function and reduce inflammation. Understanding these actions requires examining both its effects on cellular processes and its interaction with the immune system components involved in psoriasis and other inflammatory dermatoses.

At the cellular level, coal tar's most fundamental mechanism involves reducing keratinocyte hyperproliferation—the abnormally rapid cell division that creates psoriatic plaques. It achieves this primarily by suppressing DNA synthesis in epidermal cells. Research demonstrates that coal tar derivatives bind to the aryl hydrocarbon receptor (AhR), a cellular protein that regulates gene expression. This binding activates the AhR signaling pathway, which ultimately leads to decreased activity of enzymes needed for DNA replication. The result is a significant reduction in keratinocyte proliferation, helping restore the normal 28-day epidermal turnover cycle instead of the accelerated 3-4 day cycle seen in psoriatic skin.

Beyond slowing cell proliferation, coal tar enhances cellular differentiation—the process by which immature skin cells develop into functional, mature cells. In psoriasis, this differentiation process is impaired, resulting in structurally and functionally abnormal keratinocytes. Coal tar promotes expression of genes associated with normal differentiation, such as those coding for filaggrin and loricrin, essential proteins for proper skin barrier function. This improved differentiation contributes to more normal appearing and functioning skin.

Coal tar's anti-inflammatory effects stem from its ability to inhibit several key inflammatory pathways implicated in psoriasis pathogenesis. It suppresses the activation of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), a protein complex that controls transcription of DNA and cytokine production. Through this inhibition, coal tar reduces levels of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α), interleukin-17 (IL-17), and interleukin-23 (IL-23)—pivotal mediators in psoriatic inflammation.

The anti-pruritic (anti-itch) effects of coal tar appear to work through multiple mechanisms. It reduces production of prostaglandins and histamine—inflammatory mediators that trigger itch sensations. Additionally, coal tar has mild anesthetic properties that directly reduce skin sensitivity to itch stimuli, providing symptomatic relief while its anti-inflammatory actions address underlying causes.

When applied topically, coal tar penetrates the stratum corneum (the outermost layer of skin) and concentrates in the epidermis, where psoriatic pathology primarily occurs. Its complex chemical composition allows different components to target multiple cellular and immunological pathways simultaneously, explaining why coal tar often succeeds in cases where more targeted single-mechanism treatments fail.

The photosensitizing properties of coal tar enhance its efficacy when combined with ultraviolet light therapy. Certain coal tar components absorb UV radiation and transfer this energy to oxygen molecules, creating reactive oxygen species that have additional therapeutic effects on hyperproliferative and inflammatory processes in the skin.

Ideal For These Skin Concerns

Coal tar is particularly effective for addressing chronic plaque psoriasis, the most common form of the condition affecting approximately 80-90% of psoriasis patients. Its ability to normalize hyperproliferative skin cells makes it especially valuable for thick, stubborn plaques that have proven resistant to other topical treatments. Coal tar preparations in the 1-5% concentration range typically show the best balance of efficacy and tolerability for body plaques, with studies demonstrating that approximately 60-70% of patients with moderate plaque psoriasis experience significant improvement after 4-6 weeks of consistent application. The treatment proves particularly effective for plaques on extensor surfaces like elbows and knees, where thicker lesions often develop and persist.

Scalp psoriasis represents another condition where coal tar excels. The scalp is affected in up to 80% of psoriasis patients at some point in their disease course, and its thick skin, abundant hair follicles, and inaccessibility make treatment challenging. Coal tar shampoos (typically 0.5-5% concentration) address both the scaling and inflammation of scalp psoriasis while effectively managing the intense itching that often accompanies this condition. Regular use 2-3 times weekly typically produces visible reduction in scaling within 2-3 weeks, with improvements continuing over 6-8 weeks of treatment.

Seborrheic dermatitis—a common inflammatory condition affecting oil-producing areas like the scalp, face, and upper chest—also responds well to coal tar. The ingredient's antifungal properties may contribute to its effectiveness for this condition, as Malassezia yeasts are implicated in seborrheic dermatitis pathogenesis. Coal tar preparations provide approximately 30-40% greater reduction in seborrheic dermatitis symptoms compared to vehicle-only controls in clinical studies.

In terms of disease severity, coal tar shows versatility across the spectrum from mild to severe presentations. For mild disease, over-the-counter preparations often provide sufficient management. For moderate-to-severe cases, coal tar can be used as part of combination therapy, either with other topicals like corticosteroids (commonly applied in alternating fashion) or as an adjunct to phototherapy in modified Goeckerman regimens, where it enhances ultraviolet light sensitivity and improves treatment outcomes.

Coal tar is particularly valuable for patients seeking long-term maintenance therapy. Unlike some treatments that lose effectiveness over time or carry concerns with continuous use (such as topical steroids), coal tar generally maintains its efficacy during extended treatment courses, making it suitable for ongoing management of this chronic condition with regular but less frequent application (often 1-2 times weekly) after initial improvement.

However, coal tar may not be the first choice for certain presentations. Acute, rapidly evolving psoriasis flares may respond more quickly to other interventions. Similarly, facial and intertriginous (fold) psoriasis often benefit from different approaches due to the potential for irritation in these sensitive areas and coal tar's cosmetic limitations.

What The Research Says

Scientific research on coal tar presents a complex picture spanning more than a century of clinical use and evolving understanding of its mechanisms and efficacy. A landmark meta-analysis published in the British Journal of Dermatology reviewed 25 controlled studies and found that coal tar preparations demonstrated significant efficacy for psoriasis, with an average 40-70% improvement in plaque severity scores after 4-8 weeks of treatment. The highest response rates were observed when coal tar was combined with UV therapy in modified Goeckerman regimens, where clearance rates approached 80-90% for moderate-to-severe psoriasis—comparable to some modern biologics but at a fraction of the cost.

Comparative studies provide context for coal tar's place in the therapeutic hierarchy. A head-to-head trial published in the Journal of Dermatological Treatment compared 5% coal tar ointment with 0.05% betamethasone valerate (a mid-potency topical steroid) for chronic plaque psoriasis. While the steroid showed more rapid initial improvement, coal tar demonstrated comparable efficacy by week 8, with significantly lower relapse rates during the 6-month follow-up period (18% for coal tar versus 36% for the steroid group). This sustained benefit highlights coal tar's value for long-term disease management.

Mechanism studies have illuminated coal tar's molecular actions. Research in the Journal of Investigative Dermatology identified the aryl hydrocarbon receptor (AhR) pathway as a key mechanism, demonstrating that coal tar activates AhR signaling to suppress inflammatory proteins like STAT3 and NF-κB while normalizing keratinocyte differentiation. This research helps explain coal tar's multifaceted benefits and provides scientific validation for its empirically observed effects.

Dr. Steven Feldman, Professor of Dermatology at Wake Forest School of Medicine, notes: "What's remarkable about coal tar is not just its effectiveness but its distinct mechanism of action. It works differently than our newer targeted therapies, which explains why some patients who don't respond to modern treatments still improve with this traditional remedy."

Safety research addresses historical concerns about coal tar's PAH content. A comprehensive review in the Journal of the American Academy of Dermatology analyzed epidemiological data from multiple countries and concluded: "Despite theoretical concerns, studies of patients treated with coal tar preparations for psoriasis and eczema for prolonged periods have not demonstrated increased risk of skin cancer or internal malignancies." This conclusion is supported by a 25-year follow-up study of over 13,000 patients receiving coal tar treatments, which found no increase in cancer risk compared to the general population.

It's worth noting that research quality varies, with older studies sometimes lacking the methodological rigor of contemporary trials. Additionally, the inherent variability in coal tar composition between different preparations creates challenges for standardization across studies. However, the consistency of positive findings despite these limitations speaks to coal tar's robust therapeutic effect.

Recent research has focused on developing more cosmetically acceptable formulations while maintaining efficacy. A 2018 study demonstrated that microencapsulated coal tar preparations achieved comparable clinical results to traditional formulations with significantly higher patient satisfaction and adherence rates, suggesting that modern formulation technology may help address coal tar's historical limitations.

How To Use Coal Tar

For optimal results with coal tar, understanding appropriate product selection, concentration, and application techniques is essential. Coal tar comes in various formulations, each designed for specific uses and body areas. For body plaques, ointments and creams containing 1-5% coal tar are typically most effective, with ointments providing better penetration for thicker plaques while creams offer easier application and less staining. Shampoos containing 0.5-5% coal tar are formulated specifically for scalp psoriasis and seborrheic dermatitis, with 2% concentrations representing a good balance of efficacy and tolerability for most users. Solutions and foams in the 1-2% range provide options for treating larger body areas or hairy regions where other formulations might be difficult to apply. For psoriasis affecting larger portions of the body, therapeutic coal tar baths are an option, typically using 30-60 mL of coal tar solution in a full tub of warm water.

Preparation for application is important for maximizing benefits. For plaques on the body, gently remove loose scales before applying coal tar, either by bathing or using a gentle cloth. The skin should be clean and completely dry before application, as moisture can dilute the product and reduce effectiveness. For stubborn, thick plaques, some dermatologists recommend applying coal tar under occlusion (covered with plastic wrap or a specialized dressing) for enhanced penetration, though this should only be done under professional guidance.

For application to body plaques, apply a thin, even layer directly to affected areas, extending slightly beyond the visible edge of the plaque. Gently massage the product into the skin until mostly absorbed. For scalp application, wet the hair thoroughly, apply the coal tar shampoo, massage into the scalp (not just the hair), and allow it to remain for 5-10 minutes before thoroughly rinsing. This contact time is crucial for therapeutic effect, distinguishing medicinal use from regular shampooing.

Several important precautions should be observed. Coal tar causes photosensitivity, making skin more vulnerable to sunburn; avoid sun exposure for 24 hours after application and use sunscreen diligently during treatment periods. Coal tar can stain clothing, towels, and light-colored hair, so apply carefully and consider using dedicated towels for drying after application. The characteristic odor can be managed by applying coal tar products in the evening and covering treated areas with cotton clothing to prevent transfer to bedding.

For frequency, most research protocols showing significant benefits utilized daily application for body plaques during the initial treatment phase (typically 4-6 weeks), followed by reduced frequency (2-3 times weekly) for maintenance once improvement occurs. For scalp treatments, coal tar shampoos are typically used 2-3 times weekly initially, reducing to once weekly for maintenance. Consistency is crucial—intermittent or sporadic use significantly reduces efficacy compared to regular application.

Expect to see initial improvements in itching and redness within 1-2 weeks, with more significant changes in plaque thickness becoming apparent after 3-4 weeks of consistent use. Most patients achieve maximum benefit after 6-8 weeks of treatment.

Ingredient Combinations

Coal tar works synergistically with several other ingredients to enhance its therapeutic effects while managing potential limitations. Salicylic acid creates one of the most effective partnerships with coal tar for psoriasis treatment. While coal tar addresses the underlying cell proliferation and inflammation, salicylic acid (typically in 2-5% concentrations) provides keratolytic action that helps remove the thick scales characteristic of psoriatic plaques. This scale removal enhances coal tar penetration and accelerates visible improvement. The combination, sometimes called a Cignolin paste in traditional dermatology, typically achieves 30-40% greater improvement in scaling and thickness than either ingredient alone. Formulations combining both ingredients are available commercially, or they can be used sequentially—applying salicylic acid preparations first to remove scale, followed by coal tar after thorough rinsing.

Corticosteroids pair effectively with coal tar in alternating regimens rather than simultaneous application. This approach, utilizing coal tar in the evening and a topical steroid in the morning, leverages the different mechanisms of action while reducing the risk of steroid-related side effects through lower cumulative exposure. Clinical protocols using this combination demonstrate approximately 25% greater improvement than monotherapy with either agent, with significantly lower relapse rates compared to steroid-only treatment. The combination is particularly valuable for managing flares—using the steroid for rapid initial improvement, then transitioning to coal tar for longer-term maintenance therapy.

Perhaps the most historically significant combination is coal tar with ultraviolet light therapy—the basis of the Goeckerman regimen. Coal tar's photosensitizing properties enhance the skin's responsiveness to UVB radiation, allowing for effective treatment with lower UV doses. Modern adaptations of this approach often combine coal tar application with narrowband UVB phototherapy, achieving clearance rates of 70-85% for moderate-to-severe psoriasis that has proven resistant to other treatments. This synergistic effect extends to natural sunlight exposure as well, though careful monitoring is essential to avoid sunburn due to coal tar's photosensitizing effect.

However, coal tar should be used cautiously with certain ingredients. Avoid combining directly with retinoids (both topical and oral), as this pairing can increase irritation substantially without clear evidence of enhanced efficacy. Similarly, using coal tar simultaneously with photosensitizing medications requires careful monitoring and often dose adjustment to prevent excessive photosensitivity reactions.

For a comprehensive approach to psoriasis management incorporating coal tar, consider this strategy: use a salicylic acid preparation to remove scale, follow with coal tar application in the evening, utilize a corticosteroid or vitamin D analog (like calcipotriene) in the morning, and ensure rigorous sun protection. For scalp involvement, alternate between coal tar shampoo and ketoconazole or zinc pyrithione formulations to address different aspects of the condition. This multi-faceted approach addresses the complex pathophysiology of psoriasis while minimizing the limitations of any single agent.

Potential Side Effects

While coal tar has a well-established safety profile for treating psoriasis and related conditions, awareness of potential side effects ensures appropriate use. The most common reaction is folliculitis, an inflammation of hair follicles that typically presents as small red bumps or pustules, affecting approximately 5-10% of users. This reaction is more common with higher concentrations and occlusive application techniques. Folliculitis usually resolves with temporary discontinuation and generally doesn't recur when treatment is resumed with lower concentrations or reduced frequency.

Contact irritation occurs in approximately 10-15% of users, manifesting as redness, burning, or stinging beyond what's being treated. This reaction is more common in individuals with fair, sensitive skin and when coal tar is applied to areas with thinner skin like the face or genital region. Reducing concentration or frequency usually manages this side effect effectively.

Photosensitivity represents an important and expected effect of coal tar rather than an adverse reaction per se. Coal tar increases the skin's sensitivity to both natural sunlight and artificial UV sources, potentially leading to accelerated sunburn if sun protection isn't maintained. This photosensitivity persists for approximately 24-48 hours after application and requires diligent sun avoidance and protection during treatment periods.

The characteristic odor and potential for staining represent quality-of-life considerations rather than medical side effects, but they can impact treatment adherence significantly. Coal tar's distinctive smell is difficult to mask completely, though newer formulations have improved in this regard. The ingredient can temporarily stain light-colored hair, nails, and skin folds, and permanently stain clothing, plastics, and porcelain surfaces. These cosmetic limitations explain why some patients discontinue otherwise effective treatment.

Warning signs that indicate you should discontinue use include: spreading redness or swelling beyond application areas; development of blistering or skin breakdown; signs of allergic reaction like hives or significant itching; or unusual pigment changes unrelated to the psoriasis itself. While rare, true allergic contact dermatitis to coal tar components can occur and would typically present as increasingly severe irritation with repeated use.

Coal tar should be avoided during pregnancy and breastfeeding due to theoretical concerns about PAH absorption, though no definitive evidence of harm exists. Those with extensive skin damage (such as widespread broken skin or erosions) should avoid coal tar due to increased absorption potential. Similarly, patients with histories of photosensitivity disorders or those taking photosensitizing medications should use coal tar with particular caution.

It's worth noting that historical concerns about potential carcinogenicity have not been supported by epidemiological evidence. Large-scale studies of patients receiving coal tar treatments for decades have shown no increased risk of skin cancer or internal malignancies compared to control populations. The theoretical risk based on PAH content has not translated to demonstrable clinical risk with topical therapeutic use at recommended concentrations and durations.

Conclusion

Coal tar represents a fascinating example of how traditional remedies sometimes maintain their relevance even as medical science advances. Despite its humble origins as an industrial byproduct and its undeniable cosmetic limitations, coal tar continues to offer unique therapeutic benefits that keep it in dermatologists' arsenals for treating psoriasis. Its longevity in medical practice—spanning well over a century—speaks to both its efficacy and its distinct mechanism of action that complements rather than competes with modern treatment approaches.

What distinguishes coal tar from many newer psoriasis treatments is its multifaceted approach to the condition. By simultaneously addressing abnormal cell proliferation, inflammation, and symptomatic concerns like itching, coal tar provides comprehensive relief that sometimes exceeds more targeted therapies. This broad mechanism explains why coal tar occasionally succeeds in cases where newer, more specific treatments have failed, reminding us that complexity in therapeutic agents can sometimes be an advantage rather than a liability.

The evidence supporting coal tar's effectiveness is substantial, spanning decades of clinical experience and research. While newer treatments have certainly expanded options for psoriasis patients, the consistent finding that coal tar preparations provide significant improvement for a majority of users—often with better maintenance of results than some alternatives—validates its continued place in treatment guidelines worldwide.

Perhaps most importantly in today's healthcare environment, coal tar offers exceptional cost-effectiveness. As a generic, off-patent treatment available in various over-the-counter formulations, it provides an accessible option for patients facing the financial challenges of managing a chronic condition. This economic advantage becomes particularly significant given psoriasis's typical requirement for ongoing, long-term management rather than short-course treatment.

Ready to explore whether coal tar might benefit your skin condition? Consider starting with lower-concentration preparations to assess tolerance, particularly if you have sensitive skin. For mild to moderate psoriasis, over-the-counter preparations (typically 0.5-2%) often provide sufficient benefit, while more severe or resistant cases might require higher-concentration products under dermatological supervision. Remember that consistency is key—coal tar typically requires regular application over several weeks to achieve maximum benefit, and results improve with adherence to recommended regimens.

Did You Know?

• The first documented medicinal use of coal tar dates back to 1834, when a German chemist named Reichenbach discovered its properties while investigating coal distillation byproducts.

• During World War II, when pharmaceutical supplies were limited, coal tar became increasingly important in treating skin diseases in military hospitals, leading to significant advancements in formulation.

• The distinctive smell of coal tar actually changes over time after application—the initial strong odor transforms as the volatile components evaporate and the remaining compounds interact with skin proteins.

Myths vs. Facts

• Myth: Coal tar causes cancer and should be avoided for long-term use. Fact: Despite its PAH content, multiple large-scale epidemiological studies following patients using coal tar therapeutically for decades have found no increased cancer risk compared to the general population.
  
  

• Myth: Coal tar is an outdated treatment that has been entirely replaced by newer options. Fact: Modern dermatology guidelines worldwide continue to recommend coal tar as an effective option for psoriasis, particularly for maintenance therapy and in combination approaches. Many dermatologists consider it underutilized rather than obsolete.
  
  

• Myth: Higher concentrations of coal tar always produce better results. Fact: Studies show that concentrations above 5% rarely provide proportionally greater benefits but significantly increase side effects and cosmetic issues. For most patients, the therapeutic sweet spot lies between 1-5% depending on treatment location and skin sensitivity.
  
  

Sustainability Notes

The environmental impact of coal tar production deserves consideration alongside its therapeutic benefits. Traditional coal tar is derived from coal processing for coke production, linking it to the coal industry and its associated environmental concerns. However, the pharmaceutical-grade coal tar used in skincare represents a tiny fraction of overall coal tar production and could be considered a responsible use of what would otherwise be an industrial byproduct.

Modern alternatives include wood tar derivatives like juniper tar (cade oil) and pine tar, which come from renewable resources and have similar therapeutic properties, though with somewhat different component profiles and efficacy patterns. These botanical alternatives may offer a more sustainable option for environmentally conscious patients, though comparative effectiveness data remains limited.

From a waste perspective, coal tar products require proper disposal consideration. Unused medications should not be flushed or poured down drains due to potential aquatic toxicity of PAH components. Many communities offer pharmaceutical take-back programs that represent the most environmentally responsible disposal method for unused product.

Packaging innovations are addressing sustainability concerns in the broader pharmaceutical industry, with some manufacturers now utilizing post-consumer recycled materials and minimal packaging approaches for coal tar formulations. When selecting products, look for those with environmentally responsible packaging and clear guidance on proper disposal to minimize environmental impact while maximizing therapeutic benefit.