Coal tar was discovered in 1665 and used for medical purposes as early as the 1800s. Its most common industrial use is as a railroad tie preservative, and it’s also used in the surfacing of roads.
Coal tar is a thick dark liquid that is a byproduct of the production of coke, a solid fuel that contains mostly carbon, and coal gas. It goes by other names such as liquor carbonis detergens (LCD) and liquor picis carbonis (LPC).
Topical coal tar is a commonly used option to treat symptoms of atopic dermatitis (eczema), seborrheic dermatitis (a leading cause of dandruff), and psoriasis. It’s most frequently used as a treatment for psoriasis of the scalp, palms, and soles, which are traditionally hard to treat. You’ll find it as an ingredient in dermatological shampoos, soaps, as well as topical lotions and creams.
How Does it Work?
Coal tar isn’t a cure for serious skin conditions, but may reduce symptoms such as itching, flaking, and scaling. It works by causing the skin to shed dead skin cells from its top layer while slowing down the growth of new skin cells. It is in a class of drugs known as keratoplastics.
Although coal tar was listed as a known human carcinogen in the first Report on Carcinogens from the U.S. Federal Government, topical coal tar is generally recognized as safe by the FDA, and is listed in the World Health Organization’s list of essential medicines. If the amount of coal tar in a product falls between .05 and 5.0%, it can be sold without a prescription.
In California, coal tar products come with a cancer warning. To be clear, though, studies have failed to show an increase in cancer risk from topical coal tar treatments, and the risk assessment is based on a link between lung cancer and exposure to industrial coal tar.
Coal tar therapy is often a good choice for treating children with psoriasis or eczema, because of its track record of safety. That’s why in pediatric dermatology, it is often used as an alternative to drugs and/or topical steroids — since children have a higher rate of drug absorption and risks for drug toxicity.
Side Effects of Topical Coal Tar
Coal tar does have some potential negative side effects that are helpful to know:
- It can increase sensitivity to UV exposure, so stay out of the sun and tanning beds when using coal tar products
- Some people can be sensitive to coal tar, resulting in an acne-like breakout, itching, or worsening psoriasis. Stop using coal tar products immediately if you have burning or stinging or any of the above symptoms, and talk to your dermatologist.
- Avoid using coal tar products near the nose, eyes, rectal or genital area, as it may result in severe irritation.
- If using a coal tar shampoo for scalp psoriasis, the shampoo may leave the hair dry and brittle.
- Coal tar products can stain clothes and skin, and smell unpleasant.
- Those who are pregnant or nursing should avoid it as no studies are available on coal tar’s possible effects on the developing fetus or nursing babies.
- Topical coal tar products are best used as an alternative to corticosteroids. However, some coal tar products may also contain topical steroids, so be cautious. In some individuals, topical steroids can lead to a more severe skin condition known as TSW (topical steroid withdrawal).
Topical coal tar products may be helpful in managing symptoms from skin conditions such as psoriasis, eczema, and seborrheic dermatitis, especially in children. Yet since it cannot address the underlying root cause of the condition, we encourage you to explore additional treatments that do, like TCM herbal medicine, to effect a more lasting recovery.
Want to Learn More About Skin Health?
Click HERE to get the Amethyst Holistic Skin Solutions Newsletter. You’ll receive interesting information about skin health via articles, before/after pictures, case studies of Amethyst patients, videos, interviews and more. Feel free to share this article with someone who you think may benefit.
About the Author
Olivia Hsu Friedman, LAc, Dipl.OM, DACM, Cert. TCMDerm, is the owner of Amethyst Holistic Skin Solutions and treats Acne, Eczema, Psoriasis, and TSW. Olivia treats patients via video conferencing using only herbal medicine. Olivia is Chair of the Board of Directors of the American Society of Acupuncturists, serves on the Advisory Board of LearnSkin, and is a faculty member of the Chicago Integrative Eczema Group sponsored by the National Eczema Association.