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Coal Tar for Seborrheic Dermatitis: A Research Summary

Book Extract

This article is an extract from: Seborrheic Dermatitis - The Owner's Manual; a book dedicated to understanding seborrheic dermatitis. See the book overview page for more information.

Coal tar has a long history of use in dermatology for treating various skin conditions like psoriasis, eczema, and seborrheic dermatitis (dandruff). In this article, we’ll take a look at the research behind using coal tar to treat seborrheic dermatitis.

What is Coal Tar?

Coal tar is a thick, dark liquid that is a byproduct of the process of converting coal into coke or gas [1]. It contains over 10,000 different chemicals, including polycyclic aromatic hydrocarbons (PAHs) [2].

Medicinally, coal tar has been utilized for over 150 years. It has anti-inflammatory, antibacterial, antifungal, antipruritic (anti-itch), and keratoplastic (modifies skin growth) properties [3, 4].

Mechanism of Action

Coal tar works through multiple mechanisms:

  • Slows skin cell reproduction: Coal tar reduces the excessive skin cell production associated with psoriasis and seborrheic dermatitis [2].
  • Normalizes inflammation: It reduces cytokine and chemokine production, lowering inflammation [5].
  • Reduces sebum production: Seborrheic dermatitis involves increased sebum production. Coal tar normalizes this [2].
  • Kills fungi: It has antifungal effects against malassezia yeasts implicated in seborrheic dermatitis [3].

Efficacy Against Fungi

There are two key studies examining coal tar’s antifungal effects:

  • A 1993 study compared a coal tar gel to ketoconazole gel against malassezia yeast. Results showed similar effectiveness between the two gels [6].
  • A 1995 study tested coal tar against multiple malassezia yeast strains. Coal tar inhibition varied widely across strains (MIC 3-50 μm/ml). This was inferior to zinc pyrithione and selenium sulfide, but coal tar is used at higher concentrations in treatment [3].

So while coal tar may not be the most potent antifungal, high concentrations likely compensate for this.

Safety Profile

Thanks to over 150 years of use, the safety profile of topical coal tar is well-established:

  • Multiple long-term studies over decades have not revealed any serious safety issues [7].
  • Side effects are generally mild, including irritation, sun sensitivity, folliculitis, and contact allergy [8].

There were initially concerns about skin cancer risk from coal tar due to PAH content. However, well-designed epidemiology studies have not found clear evidence of increased skin or internal cancer risk [8, ].

So while not completely risk-free, coal tar appears relatively safe for topical use under medical supervision.

Comparison to Other Tars

Other tars beyond coal tar are also used medicinally, including:

  • Pine tar: Derived from pine wood. Used primarily for the skin and respiratory conditions. Less research than coal tar [9].
  • Sulfonated shale oil: Byproduct of shale oil industry. Used for psoriasis, eczema, and seborrheic dermatitis. Considered to have a better safety profile than coal tar [10].

While less studied, these alternative tars may offer comparable benefits to coal tar for seborrheic dermatitis treatment.

Drawbacks of Tars

The main drawbacks of coal tar and other tars are:

  • Strong odor: Requires fragrances to mask smell, which can cause contact allergy [8].
  • Staining: Leaves behind a dark color on skin and clothing [2].

These factors have likely reduced tar’s popularity compared to newer colorless and fragrance-free treatments.


  1. Coal tar has a long history of use for various dermatological diseases, including strong evidence supporting its efficacy in seborrheic dermatitis treatment.
  2. It works through multiple mechanisms: reducing inflammation, normalizing skin cell/sebum production, and antifungal activity.
  3. Thanks to decades of use, coal tar’s safety profile is well-established, with most side effects being minor irritation.
  4. However, disadvantages like strong odor and staining may make patients hesitant to use coal tar or prefer newer treatment options.

Overall, while not a first-line treatment, coal tar remains a potential option for managing seborrheic dermatitis symptoms under medical guidance. Other tars may offer similar benefits with improved safety and tolerability. More research comparing tar preparations head-to-head could help clarify their risk/benefit profiles.

Book Extract

This article is an extract from: Seborrheic Dermatitis - The Owner's Manual; a book dedicated to understanding seborrheic dermatitis. See the book overview page for more information.


  1. Heinz-Gerhard Franck "THE CHALLENGE IN COAL TAR CHEMICALS" American Chemical Society (ACS) 55.5 (2005): 38-44.
  2. Sahil Sekhon, Caleb Jeon, Mio Nakamura, Ladan Afifi, Di Yan, Jashin J Wu, Wilson Liao, Tina Bhutani "Review of the mechanism of action of coal tar in psoriasis." The Journal of dermatological treatment 29.3 (2018): 230-232. PubMed
  3. P Nenoff, U F Haustein, A Fiedler "The antifungal activity of a coal tar gel on Malassezia furfur in vitro." Dermatology (Basel, Switzerland) 191.4 (1996): 311-4. PubMed
  4. Luigi Naldi, Janouk Diphoorn "Seborrhoeic dermatitis of the scalp." BMJ clinical evidence 2015 (2018). PubMed
  5. Ellen H. van den Bogaard, Judith G.M. Bergboer, Mieke Vonk-Bergers, Ivonne M.J.J. van Vlijmen-Willems, Stanleyson V. Hato, Pieter G.M. van der Valk, Jens Michael Schrufder, Irma Joosten, Patrick L.J.M. Zeeuwen, Joost Schalkwijk "Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis." American Society for Clinical Investigation (2013).
  6. M C Wright, F Hevert, T Rozman "In vitro comparison of antifungal effects of a coal tar gel and a ketoconazole gel on Malassezia furfur." Mycoses 36.5-6 (1994): 207-10. PubMed
  7. M R Pittelkow, H O Perry, S A Muller, W Z Maughan, P C O'Brien "Skin cancer in patients with psoriasis treated with coal tar. A 25-year follow-up study." Archives of dermatology 117.8 (1981): 465-8. PubMed
  8. Judith H. J. Roelofzen, Katja K. H. Aben, Pieter G. M. van der valk, Jeanette L. M. van houtum, Peter C. M. van de kerkhof, Lambertus A. L. M. Kiemeney "Coal tar in dermatology." Informa UK Limited 18.6 (2007): 329-334.
  9. Kapila V Paghdal, Robert A Schwartz "Topical tar: back to the future." Journal of the American Academy of Dermatology 61.2 (2009): 294-302. PubMed
  10. M H Schmid, H C Korting "Coal tar, pine tar and sulfonated shale oil preparations: comparative activity, efficacy and safety." Dermatology (Basel, Switzerland) 193.1 (1997): 1-5. PubMed
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About Michael Anders

After being affected by seborrheic dermatitis, I have made it my goal to gather and organize all the information that has helped me in my journey.

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