Tar products that are used to treat
psoriasis come in several forms. Coal tar is available as a gel, cream, ointment, liquid, or shampoo. You can get most tar
products without a prescription.
Tar therapy usually starts with a product that contains only a
small amount of tar. The amount may be increased every few days (unless your
symptoms aren't improving or you have side effects).
Tar products may be used with ultraviolet B (UVB) light therapy.
This is called Goeckerman treatment. This combination may be given to a person
who is in the hospital, usually over a period of 2 to 3 weeks. It may also be
given in sessions at a doctor's office or at home. A session
usually lasts 8 hours, and 1 to 6 sessions a week are needed.
The Ingram regimen combines bathing with a coal tar product,
anthralin cream, and getting UVB light therapy. The
treatment takes about 3 weeks and can be done in the hospital or in a day
How It Works
Coal tar makes
psoriasis plaques thinner and less red.
Coal tar helps improve the effectiveness of other treatments, such
as ultraviolet light or
Why It Is Used
Coal tar products are used to treat mild or severe psoriasis plaque
that affects small areas of the skin.
When psoriasis covers more of the body, tar may be used together
with UVB light therapy.
How Well It Works
Tars have been used to treat psoriasis for many years, but studies
disagree about how well they work.1
In general, tar together with UVB light is thought to work better than tar alone.
Coal tar preparations are generally thought to be safe. There have
been some concerns of cancer-causing chemicals in coal tar. But the U.S. Food
and Drug Administration (FDA) reports that the chemical concentrations in
over-the-counter coal tar are at safe levels. Use coal tar carefully when the
skin rash is inflamed or is near the eyes or in skin folds.
See Drug Reference for a full list of side effects. (Drug Reference
is not available in all systems.)
Naldi L, Rzany B (2009). Psoriasis (chronic plaque),
search date August 2007. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
How this information was developed to help you make better health decisions.