Anthralin (Dithranol)

Anthralin is a synthetic version of chrysarobin, a natural substance derived from the araroba tree of South America that has been used to treat psoriasis for nearly 100 years. It is available as a cream, ointment and scalp lotion. Lower concentrations can be left on overnight, while stronger ones (1% or higher) should be left on for 15-30 minutes. Short contact with a high concentration works better than longer contact with a low concentration. Short contact anthralin is an effective treatment option for mild-to-moderate psoriasis.

In hospital-based psoriasis day care centers, one of the treatment approaches used is known as the Ingram regime, which involves the combination of anthralin paste, coal tar baths, as well as ultraviolet light. Short contact tar and anthralin, when combined with UVB, can clear psoriatic lesions in about 70% of patients, and the response can be maintained for about 6 months.

How the treatment works

Anthralin slows down the growth of skin cells and has anti-inflammatory actions
Used to treat plaque and guttate psoriasis

Advantages/Benefits

Good safety profile
Easy to use
Beneficial for localized areas of psoriasis
Short contact anthralin can be administered at home
Treatment with anthralin can achieve a longer period of remission over corticosteroids
May be used in combination with both UVB phototherapy and PUVA
Negligible amounts are absorbed into the body

Disadvantages/Risks

Anthralin can cause staining (purple/brown color) of your clothes, skin and hair
Skin irritation (soreness and redness) may occur
Avoid using anthralin on the face, genitals, or in the skin folds
Not suitable for use on inflamed lesions
Patients may be slow to respond
Limited availability in some areas

Comments & Suggestions

Anthralin's use has been limited due to staining and skin irritation.
The unpleasant effects can be minimized by applying the medication only to the patches of psoriasis and avoiding uninvolved skin.
Lower concentrations or less contact time should be maintained on more sensitive sites.
Burning and irritation should resolve once the anthralin is washed off with cool water.