Warts and their treatment with Diphencyprone

Warts are caused by infection of the skin or mucous membranes with human papilloma virus (HPV). HPVs are divided into separate genotypes on the basis of their DNA sequence.  Different HPV types may preferentially infect either cornified stratified squamous epithelium of skin or uncornified mucous membranes. The appearance of the lesion is influenced not only by viral type but also by environmental and host factors

How are they treated?

There is no single treatment that is 100% effective and different types of treatment may be combined. Sometimes, warts may respond to freezing, various over-the-counter acids, or other destructive methods. There are also a lot of mysterious and wonderful treatments that have been recommended in the past, on the basis of little scientific evidence. When all these methods fail, there are several tricks available to the Dermatologist to deal with warts. One of these is Diphencyprone Immunotherapy.

What is Diphencyprone Immunotherapy?

Diphencyprone (DPC) is a chemical which causes contact sensitization, or allergic reaction to it. Two steps are required to trigger your body's immune system with a contact sensitizer:

The contact sensitizer is put on a small area of your skin. Your skin may become red, swollen, itchy, or blistered. This kind of skin reaction is a sign that the contact sensitizer will work. Then you have to wait for three or four weeks to give your body time to develop specific sensitivity to the chemical. The next time the sensitizer is applied to your skin, your body's immune system will react to it, and the affected area will develop an allergic (immune) reaction. Therefore, when DPC is applied to the warts after filing them, this ‘tricks’ the immune system into noticing the warts, and causes them to get inflamed, destroying them. Repeat treatments (increasing the concentration of the sensitizer if no reaction occurs) are made every week or so until the immune reaction has cleared the warts. Usually, the treatment is entirely painless and very much better than the freezing treatments! You will probably remain allergic to DPC for the rest of your life, however DPC is not found outside of the clinic in the natural environment or at home, so you won’t develop allergic reactions to anything else. If you develop more warts in the future, it can be used again if required.

How good is it?

Two large open studies of diphencyprone have shown very encouraging results. In one, diphencyprone was applied weekly for 8 weeks in 134 patients and gave a response rate of 60% (complete clearance 44% of individuals at 4 months).  In another study, of 48 patients treated on average every 3 weeks, 88% were clear within 14 weeks.

Any drawbacks?

Some patients cannot be sensitized whilst a few might get troublesome eczematous reactions. These can be itchy and sore, but are usually short-lived and respond to topical steroid ointments. Contact sensitizers are not recommended for women who are pregnant. Currently, DPC is an expensive chemical, and treatment with DPC is still regarded as being experimental as its long-term safety profile remains to be fully evaluated. By accepting this leaflet and discussing the treatment in clinic you are considered informed of these risks and consent for treatment is implied.

Further Reading    http://www.bad.org.uk/healthcare/guidelines/cw.asps