Tar

What is tar and how does it work?
Tar used for medicinal purposes is derived from both coal and wood (e.g., juniper, pine). However, coal tar is the type used most commonly to treat psoriasis. Tar can help slow the rapid proliferation of skin cells and restore the skin's appearance. In addition, tar can help reduce the inflammation, itching and scaling of psoriasis.How well does tar work?
Patients may see improvement within a couple of weeks of starting tar treatment, but it may take up to eight weeks to see the maximum benefit.The best candidates for use of tar as a primary treatment are people with limited psoriasis or those with well-defined lesions.
When reading labels on tar products, including shampoos, keep in mind that generally the higher the concentration of tar, the more potent the product. Also remember that the greater the concentration of tar, the greater the odor and mess the product may cause.
How do you apply tar to the skin?
Tar can be applied directly to the psoriasis lesion, added to bath water or applied to the scalp. Follow the directions supplied on the tar medication or the instructions from your doctor. Tar medications are generally left on the skin for at least two hours.Apply tar medications in the same direction the hair grows. Applying against the direction of hair growth can cause inflammation and pimple-like eruptions at the base of the hair follicles. This is called folliculitis.
Tar can stain clothing and bed linen. To help reduce staining, allow the medication to air dry on the skin before covering it with clothing.
Tar shampoos
Tar is sold in special shampoo formulations to treat scalp psoriasis. Medicated tar shampoo is normally left on the scalp for five to 10 minutes before being rinsed out, to allow the shampoo to penetrate the scales. If scaling is sufficiently heavy, pretreatment with a scale remover (known as a keratolytic) may help the tar shampoo better penetrate the lesions.The tar shampoo can be followed by a more cosmetically pleasing shampoo or conditioner. Tar shampoos should primarily be considered a medication, rather than a hair cleanser.
Tar can stain bleached, light blond and gray hair. Because tar gels usually cause less staining, they may be a good alternative to other forms of tar products for people with light-colored hair.
Tar in the bath
Tar solutions can be added to bath water for a 15- to 30-minute soak. Tar bath solutions are generally considered ineffective at clearing psoriasis lesions, but they can reduce itching and scaling.Side effects of using tar
Tar can irritate and redden the skin. Test a tar product on a small area of the skin first. If reddening occurs, try applying the tar on top of a moisturizer. Or, have a pharmacist mix 5%, 10% or 20% Liquor Carbonis Detergens (LCD), a prescription coal tar, with Aquaphor, an OTC moisturizing agent.It may be more difficult to find OTC tar medications in California, due to state guidelines regarding tar products. As of January 2002, California requires OTC coal tar shampoos, lotions and creams that contain more than 0.5% coal tar to be labeled with cancer warnings. As a result, some companies have stopped selling their products in California or replaced coal tar with another active ingredient. However, the U.S. Food and Drug Administration (FDA) maintains that OTC products with coal tar concentrations between 0.5% and 5% are safe and effective for psoriasis and that no scientific evidence suggests that the coal tar in OTC products is carcinogenic.
Studies show some of the chemicals in coal tar may cause cancer, but only in very high concentrations, such as in coal tar used in industrial paving. Anyone using tar regularly should be aware of the signs of skin cancer and have a dermatologist recommend a skin cancer checkup schedule.
Using tar with other treatments
The Goeckerman regimen
In 1925, William H. Goeckerman, M.D., at the Mayo Clinic, proved the benefit of combining tar with ultraviolet light B (UVB) phototherapy to treat psoriasis. The combination of intensive tar and UVB treatment was named after him, and it remains a very effective treatment for severe psoriasis.
Used in a hospital or day treatment program, the Goeckerman regimen usually requires three or four weeks of treatment. It will clear psoriasis in more than 90 percent of people and can produce a lengthy remission, ranging from a few months to a year or more, depending on the individual case of psoriasis.
However, the use of this regimen has declined substantially as new and effective systemic treatments have been developed. Also, health insurance companies tend to view the energy- and time-intensive Goeckerman regimen as a less cost-effective treatment.
Day treatment programs are one alternate approach still available in a few cities around the United States. While in a day treatment program, the individual receives intensive light and tar treatments but returns home or to a temporary residence in the evening.
Also, less involved forms of the Goeckerman regimen, referred to as modified Goeckerman, are provided in a doctor's office. In these instances, a doctor may direct the patient to apply the tar at home and then come into the office or clinic for the light treatment. Tar is applied to the skin about two hours prior to exposure to UVB, then wiped off before UVB exposure.
Using low doses of UVB, a person will generally start out with a 30-second to 1-minute dose of light. These dose times are gradually increased until the psoriasis lesions clear or reach maximum improvement.
Tar can be combined with home phototherapy. However, given the possible risk of severe burning, a doctor must be consulted in devising a home-care regimen that combines tar and UVB.
For more information, see phototherapy.
What about tar and sun?
The light-sensitizing properties of tar make natural sunlight and tar a potentially dangerous combination. Be sure to use sunscreen and monitor your sun exposure to avoid a sunburn. Natural sunlight by itself can be helpful for psoriasis, but some dermatologists recommend completely avoiding sun exposure of tar-treated skin. Wash tar off thoroughly if your skin is going to be exposed to the sun. Be aware that tar remains active on the skin for at least 24 hours, and the increased risk of burning continues throughout this active period.Talk to your doctor if you are interested in developing a carefully controlled treatment regimen that combines natural sunlight and tar. Together, you may be able to devise a sensible plan that utilizes the benefits of both while limiting the potential dangers.
Other considerations
For heavy applications of tar medication, occlusion with clothing such as pajamas or warm-up suits may help hold the medication in place and prevent staining of bedding and furniture. Cotton athletic socks can be helpful in covering arm or leg lesions. The toe of the sock can be cut away, and the sock pulled onto the limb to cover the medication. These kinds of wraps can be washed easily.Occlusion of tar preparations on the scalp may be recommended to enhance the treatment's effectiveness. However, airtight occlusion of tar should be avoided, such as with plastic wrap, because it increases the risk of infection and folliculitis. Occlusion with products that breathe (cotton clothing, for example) may not cause infection or folliculitis.
Tar, particularly some tar gels and lotions that contain alcohol, can also dry the skin. To avoid its drying effects, mix with a moisturizer or an emollient. Apply the emollient in a thin layer over the tar to keep the skin well-lubricated.
Coal tar contains more than 10,000 ingredients, and only about 50 percent have been identified. Therefore, coal tar products can vary dramatically from brand to brand.


