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Coal Tar

Information about Coal Tar and its use in the treatment of psoriasis.

Coal tar has been a dermatological treatment for over 150 years, both by itself and in combination with other treatments (mixing steroids with coal tar is not uncommon). It is generally lacking in serious side-effects, to the point where I’m having trouble finding information of any side-effects besides those mentioned below. The biggest complaints with coal tar are typically the smell (just like the tar-covered pilings of a pier in the summer — I like it), and messiness (it’s typically delivered in an ointment base).

A major concern of many people considering coal tar as a psoriasis therapy is cancer. While occupational exposure to coal tar (miners, asphalt workers, or chimneysweeps for example) may be responsible for some lung, skin, and scrotal cancers, as of 1996, no relationship between even high therapeutic dosages of coal tar for psoriasis and any form of cancer had been established. Some 25-year-long studies have found no increase in any form of cancer over what would be expected without coal tar.

A problem that many people are not aware of, though, is that coal tar is a photosensitizer. This fact is exploited in Goeckerman’s regimen (coal tar followed by UVB), but is not generally well-known. After applying coal tar to the skin, it is important to be more careful than normal when exposing the same skin to sunlight or other UVB light sources. The photosensitivity can make tanning and burning much more easy, and skin damage can worsen psoriasis.

Typical therapeutic concentrations of coal tar are around 10% coal tar solution, which is equivalent to 2% crude coal tar (CCT). Some products offer only 1% CCT, which seems to do little but generate complaints from people who have used 2% in the past (of course, the squeaky wheel gets the grease, so there are probably plenty of psoriatics who are satisfied with 1%). Concentrations as high as 20% CCT are available.

Coal tar should not be confused with pine tar or juniper tar, both of which were banned in 1990 by the FDA from over-the-counter products for dandruff, seborrheic dermatitis, and psoriasis due to a lack of proof that they were effective. See Ed Anderson’s online copy of the FDA Notice for more information.

Update — September 17, 2002: California’s Proposition 65 was passed back in 1986. It mandated that any product sold in California with ingredients which are known to be carcinogens be labelled as such. Each ingredient has a level specified within Prop 65, below which no label is required. This “No Significant Risk Level” (NSRL) is defined by the law to be a single extra case of cancer amongst 100,000 people who are exposed to the product for 70 years.

In 1999, Perry Gottesfeld, a private citizen in California, sued the makers of at least 20 manufacturers of shampoos containing coal tar for not carrying the legally-required warning label. Mr. Gottesfeld’s lawsuit was later consolidated with one filed by the California Attorney General. The lawsuit requires the labelling change, along with penalties for the time the products have not been in compliance with the law. According to the National Psoriasis Foundation, Mr. Gottesfeld stands to recoup 25% of the damages collected by the lawsuit.

The lawsuit was officially opposed by the National Psoriasis Foundation, on the grounds that a warning label would either unnecessarily discourage psoriatics from buying coal tar products, or would result in companies making coal tar products dropping the coal tar or reducing its strength. The FDA states that coal tar shampoos in strengths between 0.5% and 5% are both safe and effective (my emphasis). Prop 65 sets the NSRL for coal tar at 0.5%, meaning every product the FDA has deemed to be safe requires a cancer warning label by California law.

After having trial dates for the lawsuit set and then moved a few times, it seems that the companies named in the suit are settling. Whitehall-Robbins, the manufacturer of Denorex, has already switched the main ingredient from coal tar to salicylic acid. According to the NPF, “Dermik, makers of Zetar (coal tar 1%), has decided to stop selling its products in California.” And Tegrin is being reformulated at a lower (in other words, less-effective) strength to avoid carrying the label.

Both the FDA and the NPF argued that there is no scientific basis for which a cancer warning on these products is necessary. A lawyer for the manufacturer of Tegrin was quoted by the NPF as calling the warning “alarmist.”

No solid evidence has been presented that coal tar shampoos pose a significant cancer risk (or even a measurable one). Mr. Gottesfeld, the Califorinia Attorney General, and the defendants all presented reports from various consulting firms as to what the NSRL for coal tar was. They differed by a factor of 1,450, meaning something is seriously wrong with someone’s methods of measurement. Even Mr. Gottesfeld’s number was just 1.3% of the Attorney General’s number, so something appears to be wrong, just looking at the plaintiffs’ side of things.

I still have yet to find anything that suggests that coal tar, when used medicinally, contributes to cancer in any meaningful way, so I, also, find the warning labels and settlements (to avoid even-more-costly litigation) alarming. The Attorney General was quoted as saying that the lawsuit has nothing to do with safety, just local California law. But the Denorex on my local store shelves no longer contains coal tar, and I’m over 2,500 miles away.

And just to sum-up some of the confusion about this issue I’ve already seen, coal tar products have not been banned by the lawsuit, nor have medicinal coal tar products been recently found to definitely be carcinogenic. Neither of these things is at issue.

Update — May 25, 2003: While updating the links on this page, I came across a few web sites that hint that coal tar is currently banned from all consumer goods in Europe (for example, the California Cancer Label Law Faces Court Challenge article, below). As far as I can tell, this is not true. According to the Food Additives Guide, for just one example, several coal-tar-based food additives which are banned in some European countries are not banned in others. While Norway has banned every additive derived from coal tar (and also all other uses of the substance — corrosion protection for boats, for example), the additive Azorubine (Carmoisine, E122) is also banned only in Sweden and Austria (and the U.S.A.), but can still be used in France, Germany, etc.

There is a European Union-wide ban on coal tar as a protective coating (for boats, piers, chicken coops, etc.) going into place at the end of June, 2003, but this ban doesn’t appear to affect other coal tar products. And I once had a link to an article entitled “The European Community bans Coal Tar in Cosmetics,” but the address is no longer valid. And a search of the site the article was on did not reveal a new location. However, I have no doubt that the EC has, indeed, banned coal tar in cosmetics, since the FDA has a ban on coal tar in mascara and eyeliner. Of course, cosmetic use isn’t the same as medicinal use.

In short, I can find no evidence whatsoever of a comprehensive, European Union-wide ban on all coal tar or all coal tar products — especially not medicinal products like coal-tar shampoo, which can even be found for sale on the Web with prices in British pounds.

Reader Comments

Reviewed Treatments and Information

NPF Documents About the Lawsuit

Links to other resources about the warning labels or the cancer risk

Unreviewed General Information

Unreviewed Specific Brands

The information provided here is not medical advice. This is not a self-help web site. Seek professional advice before beginning, ending, or changing treatments for any disease or condition. See the legal info page for more information.

This page created prior to 19990810, and last modified on 20100522.
Copyright © 1999 by Dave W.

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