Coal tar is often used in the treatment of psoriasis. Most individuals appear surprised when they hear the word coal tar thinking that it is an ancient and useless form of therapy. Coal tar is a blackish viscous liquid with a smell of an organic compound. The product is obtained when coal is processed to make coal gas. Coal tar is infact a mixture of many aromatic and organic compound and quite useful to treat several skin disorders.
Coal tar has been refined for the treatment of psoriasis. It is available as a soap, shampoo and ointment. It can be placed on any part of the body except the eyes, mouth or ears.
Most coal tar products are available over the counter- the most common being Psoriasin, and Tegrin.
The concentration of coal tar used for medical purposes range from 0.5-5% and has been considered effective and safe for the treatment of psoriasis.
Coal tar products are first line therapy in many cases of mild to moderate psoriasis. The products are cheap and easily available.
The coal tar has been found to decrease the ability of skin cells to divide and proliferate, thus prevents the thickening of the skin in psoriasis. Further the product has also been shown to reduce inflammation, scaling and the itching symptoms of the condition.
Coal tar treatment does not work immediately. Most individuals see the beginnings of improvement anywhere from 3-8 weeks of regular treatment
Coal tar is best suited for individuals with localized or scalp psoriasis which is of mild to moderate intensity.
One should be aware that higher concentrations of coal tar products are also available. But one also has to deal with a messy and more foul smelling product. The coal tar is generally applied on the skin or scalp anywhere from 30-120 minutes and then washed off.
The product is difficult to use and can stain everything in sight, including clothes, bed sheets and towels. The best way to avoid the staining is to allow the tar to dry up before wearing clothes. On the scalp, a shower cap may help.
Tar shampoos: These shampoos are frequently used to treat scalp psoriasis. The shampoo is left on for 5-10 minutes before rinsing it out. Coal tar can also stain light colored hair and for these individuals tar gels are recommended.
Tar in the bath: Coal tar is not really recommended for soaking in a bath tub. The product is too diluted to work in this way but can sometimes reduce the itching.
Side effects of using tar
Coal tar can cause the following side effects on the skin if left on for prolonged periods:
- skin irritation
These side effects can be reduced by applying a moisturizer prior to applying the tar.
Tar and light therapy
The combination of tar with ultraviolet light B (UVB) phototherapy is common practice in dermatology and remains a very effective treatment for severe psoriasis.
This combination therapy when used for 3-4 weeks can be used to relieve the symptoms of most severe cases of psoriasis.
Sunscreens are a must after application of coal tar. The tar must be completely washed off the skin after use and if possible all sunlight avoided to prevent a sunburn.
Because coal tar is made up of 100s of different chemicals there is a great variation in the effectiveness of products. However, in most mild to moderate cases of coal tar, irrespective of the brand name, the product is beneficial.