Anthralin, also known as Dithranol or Cignolin, is a synthetic substitute for chrysarobin, derived from the bark of the araroba tree of South America. Anthralin has been used to treat psoriasis for more than 90 years. Along with tar, anthralin was the mainstay of topical treatment of psoriasis till the introduction of steroids and calcipotriene.
How Useful is Anthralin in Psoriasis?
Anthralin can be very effective in treating plaque psoriasis. It does not work as quickly or as thoroughly as superpotent topical steroids, but unlike steroids, it has no known long-term side effects. Anthralin is also useful in treating palmoplantar psoriasis. Because of the irritant and staining properties, its usefulness in psoriasis of the face, scalp and flexures are limited.
How Does Anthralin Work in Psoriasis?
Anthralin exhibits both anti-proliferative and anti-inflammatory properties in psoriasis. In addition, modification of DNA bases and inhibition of various enzymes have been described. Epidermal calmodulin has been reported to be elevated in psoriasis and to decrease following clearance of psoriasis with treatment. Dithranol (anthralin) was demonstrated to be a potent competitive antagonist of calmodulin. Anthralin induces prolonged remission(disease free periods) than steroid induced remission in psoriasis.
How is Anthralin Applied in Psoriasis?
Following are some practical tips on applying anthralin in psoriasis:
- Apply anthralin only to psoriasis plaques; not to normal skin.
- Rub the cream well into the plaques.
- Rub off the excess cream.
- Use old clothes while using anthralin, as permanent staining of clothes can occur.
- Wash hands well immediately after applying anthralin, better to use gloves for application.
- Take care to avoid anthralin near the eyes, face or folds.
- Anthralin has to be prepared fresh to be effective. Its shelf life is 6 months.
What is Short Contact Anthralin Therapy?
Short contact anthralin therapy or minutes therapy consists of a regimen in which a high concentration of anthralin, 1% or greater, is applied for minutes to an hour. With this regimen, household exposure to the anthralin is minimized, but results are as effective as overnight application of lower concentrations of anthralin. In a modern version of this regimen, anthralin in concentrations of 1% or greater is applied for 5 minutes on the first day. Daily applications continue with increases up to 5 minutes every other day until patients develop mild irritation. The period of application is then maintained until clearing.
Is Anthralin Combined With Any Other Treatments in Psoriasis?
Combining anthralin with other treatments, including UVB treatments, PUVA (the use of the light-sensitizing drug psoralen plus ultraviolet light A), tazorac or topical steroids, may improve the response to treatment.
What is the Ingram Regimen?
The Ingram regimen is a combination of anthralin paste and a coal tar bath followed by UV exposure. Anthralin is applied to psoriasis plaques as a thick paste. This is usually done as a day care regimen, clearing of the lesions usually takes about 3 weeks.
What are the Side Effects of Anthralin?
- Anthralin is known to be a skin irritant, and the irritation a patient experiences is directly related to the strength of the product being used.
- Anthralin also stains skin, clothes, furniture etc.
It is not known if anthralin is safe during pregnancy, though no systemic side effects have been reported so far.
How are the Side Effects of Anthralin Overcome?
Recently, the development of new vehicles has led to better acceptance of anthralin for the treatment of psoriasis. Micanol is a 1% anthralin formulation in a temperature-sensitive vehicle that releases the active medication at skin surface temperatures. Micanol must be washed off with cold water because anthralin can be released from the temperature-sensitive vehicle by warm water.
Much of the irritation and staining from anthralin use can also be prevented with the application of triethanolamine, a nonsteroidal chemical used for many years as a stabilizer in soaps and cosmetics.
Next: Calcipotriene in Topical Treatment of Psoriasis.
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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.
