Coal tar treatment in psoriasis has been the mainstay of the topical treatment of psoriasis for a very long time. Used alone or in combination with ultraviolet rays or other topical agents like anthralin, coal tar is very effective in controlling the disease activity in psoriasis.
How Does Coal Tar Help in Psoriasis?
Tar in slowing down the increased turnover of epidermal cells seen in psoriasis. Tar products also reduce the inflammation, itching and scaling in psoriasis skin.
Is Coal Tar Treatment in Psoriasis Outdated?
Because of the presence of carcinogens in the tar, the treatment of generalized psoriasis with tar is discouraged nowadays, especially in the fair skinned. The odor and messiness of applications also makes it unpopular. At the same time, the cost of treatment is far less with tar compared to other topical agents and the effectiveness also outweighs the occasional risk of carcinogenic potential.
Hence coal tar treatment is still relevant among the topical therapies for psoriasis.
In Which Types of Psoriasis is Tar Indicated?
Tar is effective in the following types of psoriasis:
- Localized, well demarcated plaque psoriasis on the body.
- Scalp Psoriasis.
- Palmoplantar psoriasis affecting the hands and feet.
- Chronic stationary plaque psoriasis.
The effect of tar treatment becomes evident within a couple of weeks, but usually the plaques of psoriasis disappear by 8 weeks.
How is Tar Applied in Psoriasis?
Tar can be applied to wet skin as an ointment, left to dry for 2-3 hours, and then washed off. Tar solutions can also be added to bath; whole body soaked for 15-20 minutes, and then washed off. This is effective in relieving itching and scaling in generalized psoriasis.
Tar shampoos are effective in controlling the scalp psoriasis. The scales are removed with salicylic acid application prior to tar shampoo usage. Tar shampoo is left on the scalp for 10 minutes and then washed off. Application is repeated daily for the first week, alternate days for the second and third weeks, and when the scales are reduced, maintenance weekly twice shampooing is continued.
The regimen developed by Goeckerman in 1925 is very effective in controlling psoriasis in 80-90% of cases.
What is Goeckerman Regimen in Psoriasis?
Even after 80 years, this regimen is still found useful in many patients, especially the dark skinned.
Steps in Goeckerman regimen:
- Topical application of crude coal tar in petrolatum, at night.
- Oil bath in the morning to wash off the scales and the remaining topical application.
- Ultraviolet Light B (UVB) in redness producing (erythema) doses is applied at a day care center or hospital setting.
Previously sun exposure was utilized in Goeckerman regimen, which has been discontinued following the revelation of potential skin cancer threat when tar sensitized skin is exposed to direct sunlight.
What are The Side Effects of Tar Treatment in Psoriasis?
- The first and foremost side effect of tar treatment in psoriasis is, of course,the cancer inducing potential of tar, especially in combination with natural sun light.
- Coal tar is messy and smelly; some patients find it difficult to tolerate these.
- Tar can cause irritation on the skin; hence a small area has to be treated first to rule out any untoward effects. If the skin turns red and irritated, tar may be applied over a moisturizing cream.
- Tar application can induce inflammation in the hair follicles causing bumps in the treated area. To avoid this, tar ointment should be applied in the direction of the hair follicles, not against them.
Should I, Then, Use Tar for My Psoriasis?
According to FDA, OTC products with coal tar concentrations between 0.5% and 5% are safe and effective for psoriasis and no scientific evidence suggests that the coal tar in OTC products is carcinogenic. Also, many studies show that though some of the chemicals in coal tar may cause cancer, very high concentrations are required, as in coal tar used in road paving.
The effectiveness- risk ratio is still tilted in favor of use of tar in psoriasis. Hence, coal tar is a good treatment option for limited psoriasis.
It is to be stressed, though, that anyone using tar regularly should be aware of the signs of skin cancer and follow a dermatologist recommended regular skin cancer screen.
Next : Anthralin in Topical Treatment of Psoriasis.
Disclaimer
The information given in this article is for educational purpose only so that patients are aware of the options available. No diagnosis should be made or treatment undertaken without first consulting your doctor. If you do so, the author or suite101 will not be responsible for any consequences. The images provided are for illustration purpose only.
Hanish Babu - Dr.Hanish Babu, MD is a dermatologist and a feature writer on Suite101.com with more than 200 articles related to skin diseases on the ...
Join the Conversation