Anthralin (dithranol) is a synthetic compound used to control excessive skin cell creation, which is the main characteristic of plaque psoriasis. It is modeled after a natural extract found in Andira Araroba, a type of tree that grows abundantly in South America.

It is believed that is interacts with skin cells to reduce DNA-synthesis, which in turn prevents skin cell proliferation.

Anthralin is a powerful irritant and thus should not be applied to skin that is broken or to skin-folds.  It is recommended that it only remain on the surface of the skin for up to 30 minutest to start.  After confirming that it does not irritate the skin too much, anthralin solutions with varying degrees of potency can can be left on the skin for up to an hour before it needs to be washed off.

Anthralin comes in the form of cream, paste or ointment and is marketed under a variety of different brand names including Drithocreme, Anthra-Derm and Micanol.

Although Anthralin doesn’t start clearing psoriasis lesions as quickly as some other steroid-based alternatives, it tends to have farther reaching preventative effect on the skin once it does start taking effect.  There also tends to be less of a risk of severe break both during and after suspending use.

Anthralin-based medications such as Dritho-Scalp are yellowish creams that have a tendency to stain the skin, hair or clothing that comes in contact with it.