Coal Tar for Psoriasis - Health Tips

WHAT IS COAL TAR USED FOR?

Coal tar is often used in the treatment of psoriasis and sometimes in the treatment of eczema (dermatitis).  It may be used alone (described here) or combined with ultraviolet light treatments (described in another information sheet).

WHAT TYPES OF COAL TAR ARE THERE?

Crude coal tar is messy, stains a lot, and requires a prescription.  Refined coal tar is much less messy, stairs less, and does not require a prescription.  Examples include Estar Gel, Baker’s P&S Plus, Psorigel and T-Derm Tar Oil. Bath solutions are generally weaker than coal tar applied directly to the skin, but they can reduce itching and scaling.  Shampoos containing tar are described in a separate information sheet called Therapy for scalp psoriasis.

INSTRUCTIONS

• At bedtime, apply small amounts of a refined coal tar and rub thoroughly into the skin.  THE TAR SHOULD BE APPLIED IN THE DIRECTION THE HAIR IS GROWING.  Stroking the tar against the direction of hair growth may allow more tar penetration into the hair follicle causing inflammation and pimple-like eruptions around the hair.
• Wait for at least 5-15 minutes to allow air drying of the tar before putting on old pajamas.  This will reduce staining of these clothes.
• If desired, cotton socks or panty hose with the toes cut out can be used to cover the tar on arm or leg lesions.  Do not cover with plastic.
• Leave on overnight. If this is not feasible, leave it on for at least two hours per day.  The longer it is left on, the quicker it will work.
• Improvement would begin within a couple of weeks.  Maximum improvement will take up to two months.
• Avoid sun exposure of coal tar treated skin unless advised by your dermatologist.  He or she may advise sun or ultraviolet treatments after you apply the coal tar will increase sensitivity to the sunlight.

Keep the skin well lubricated by doing the following:  

Within three minutes after bathing and patting dry, apply a lubricant or moisturizer to the affected areas.  It is important to apply these immediately after bathing in order to trap moisture in your skin.  Greasy or oily lubricants such as Vaseline, Aquaphor, mineral oil, or baby oil are best, but many people do not like the greasy feel of these  A good compromise that is more pleasant to use but still fairly effective would be Eucerin cream or lotion or Nivea cream.  There are a large number of other effective moisturizers.  Find one that you like to use.

If the skin is still dry or itchy the rest of the day, apply moisturizing ointments, creams or lotions as often as needed to maintain moist, supple skin.

MAY I CONTINUE TO USE OTHER PSORIASIS MEDICATIONS?

In many cases, you will also be instructed to use a topical steroid cream or ointment in the morning.

DO NOT USE ANTHRALIN WHILE USING TAR.

WHAT SIDE EFFECTS DOES TAR HAVE?

Tar can irritate the skin.  If this occurs, try a different brad of tar.  If the sensitivity persists with other brands, try applying the tar on top of a very thin layer of a moisturizer such as Vaseline Petroleum Jelly, Aquaphor, or Eucerin.

Prolonged use of the tars for years may increase the risk of skin cancer.

©2011 Park City Dermatology. Last updated March 24, 2011

Coal Tar is a substance which has been used for many years to treat skin conditions, especially psoriasis and eczema. Derived from coal, coal tar contains some 10,000 compounds, some of which have not been characterized yet. These various constituents impart healing, antiinflammatory, antibacterial, antifungal,  and anti-proliferative (ie slow down excessive cell growth as is seen in psoriasis) properties.  Crude coal tar (CCT)  is a less elegant unrefined form of coal tar and has a gritty tarry consistency.  While a little difficult to find,  it can be uniquely effective in some more stubborn psoriasis cases. Coal tar extract, also called liquor carbonis detergens is an extract of CCT, which, while slightly less potent, is easier to combine with ointments.

There are several over-the counter coal tar products; Dr Berger recommends Elta Tar for its easy spreadability, low odor, and ready-mixed value sized jar. Elta Tar is available without a prescription and in stock at Dr. Berger's office 435-673-7546 for $30 for the 480g tub.