In Enzyme-Potentiated Desensitisation (EPD), an enzyme (S-glu-curonidase is used in combination with allergen extracts to enhance the desensitising effect. A wide range of extracts of allergens, foods and chemicals is mixed with the enzyme which is held by a small plastic cup against a scrape on the skin for 24-48 hours, or injected into the skin. Symptoms usually show some improvement within a week, lasting two to three months at first. Treatment is repeated about once every three months, for between one and two years.
The same mixture of extract at the same dose is given to everyone, so there is no need for individual, time-consuming testing. Elimination diets or challenge testing are less important (these are usually necessary with neutralisation) but best results are obtained if these are carried out in conjunction with treatment.
EPD is a less costly and less disruptive form of desensitisation and has achieved some impressive results. For more information, contact the National Society for Research into Allergy which has a leaflet on the subject, and Action Against Allergy.