Dithranol is a long-standing topical medication primarily used for psoriasis. This article explains its nature, how it works, proper application techniques, and important considerations for its use. Understanding this treatment can help individuals make informed decisions in consultation with their healthcare providers.
Understanding Dithranol
Dithranol, also known as anthralin, is a synthetic compound used in dermatology for over a century, with its use in treating psoriasis dating back to the nineteenth century. It was initially derived from chrysarobin, a substance obtained from the araroba tree found in Brazil. Despite newer treatments, dithranol remains a relevant option for chronic plaque psoriasis due to its effectiveness and lack of systemic side effects.
How Dithranol Treats Psoriasis
Dithranol primarily works by targeting the overproduction of skin cells, a hallmark of psoriasis. It interferes with the rapid growth and division of epidermal cells, known as keratinocytes, by inhibiting DNA synthesis. This action effectively slows down the excessive cell turnover characteristic of psoriatic plaques. Beyond its anti-proliferative effects, dithranol also exhibits anti-inflammatory properties. While its exact mechanism is not fully understood, it is thought to interfere with cellular energy supply and influence inflammatory pathways, contributing to its therapeutic effect on psoriasis.
Applying Dithranol Treatment
Dithranol is available in various topical forms, such as creams and ointments, with concentrations typically ranging from 0.1% to 2%. Application involves applying a small amount directly to psoriatic plaques once daily. A common approach is “short-contact therapy,” where dithranol is left on for a limited time, often 10 minutes to an hour, before being washed off.
Treatment might begin with a lower strength and shorter contact time, gradually increasing both as tolerated. After the specified contact time, rinse the treated area thoroughly with lukewarm water, followed by washing with soap or shampoo, especially for scalp applications. Apply dithranol accurately to avoid unaffected skin and wash hands thoroughly after use to prevent accidental transfer.
Important Considerations When Using Dithranol
Using dithranol requires careful attention due to its potential side effects. The most common issues include skin irritation, burning, and temporary staining of the treated skin, which can appear yellowy-brown to purple. This staining is harmless and fades after treatment discontinuation, but it can permanently stain clothing, linens, and other materials.
To minimize irritation, healthcare professionals often recommend starting with the lowest strength and gradually increasing it. Protecting surrounding healthy skin with an emollient before application can also help. Dithranol should not be applied to sensitive areas like the face, genitals, skin folds, or open sores, and avoid contact with eyes and mucous membranes. It is generally not suitable for widespread or acute inflammatory forms of psoriasis. Patients should always consult a healthcare professional for personalized guidance on its use.