Anthralin

Anthralin is a type of topical treatment that can be used to treat the symptoms of plaque psoriasis. It is available in the United States under the brand names Drithro-Creme HP and Zithranol. Anthralin is available as a cream as well as a scalp preparation¹.

Anthralin used to be a very common treatment for plaque psoriasis, but in recent years, new topical treatments have been developed that are easier to use and less messy than anthralin. As a result, most patients will try different topical medicines first to see if they are effective before trying treatment with anthralin².

Anthralin is applied directly to the affected area of the skin or the scalp. Improvement in symptoms may not appear until after a few weeks of treatment³.

How does anthralin work?

Psoriasis is an autoimmune condition that increases the amount of inflammation in a person’s body, which triggers the production of an excessive amount of new skin cells. These new skin cells push older skin cells to the surface of the skin before they can be shed naturally. The buildup of older skin cells causes psoriasis plaques to form on the skin.

Anthralin works by slowing down the rate at which those new skin cells are produced and reducing inflammation. For many patients, this has the effect of removing the scaly surface of plaques and making the affected skin feel smoother³.

What are the possible side effects?

Anthralin can be effective in treating symptoms of psoriasis, and it has no long-term side effects that are known. However, it can also cause skin irritation and can stain anything that it touches, including hair, clothes, bedding, plastics, and countertops. Light-colored hair can be particularly prone to staining¹.

To deal with the messiness and irritation, patients may use anthralin as short-contact therapy, in which the medicine is only applied for a small amount of time (20-30 minutes) and then it is washed off. A medicine called triethanolamine (CuraStain) contains a chemical that can help to reduce the irritation that short-contact treatment with anthralin can cause. It is applied for 1-2 minutes before the anthralin is washed off. After the anthralin is washed off and the skin is dried, the CuraStain can be re-applied to the treated area of skin⁴.To avoid applying to unaffected skin, apply zinc oxide or petroleum jelly to the edges of the affected area prior to application.

Anthralin stains on the skin or the hair will fade away, but it can take a while. To avoid staining your hands while applying anthralin, using disposable gloves can be helpful. For stains on fabric, clothing, or bedding, washing them in detergents containing household bleach (such as Clorox) can be useful⁶.

People who have kidney conditions may be advised not to try treatment with anthralin. People with fair skin may also be advised to avoid anthralin.

Other things to know

Anthralin can be used safely and effectively in combination with several other types of treatments for psoriasis. For example, it can be used with⁶:

• • topical corticosteroids
  • Tazorac (tazarotene), a type of drug called a topical retinoid
  • phototherapy with ultraviolet light B (UVB)
  • phototherapy with ultraviolet light A plus a light-sensitizing drug called psoralen (PUVA)