Retesting 50 patients with stasis dermatitis after a period of time (3–25 months) revealed significantly less positive patch test results (p < 0.05). All procedures were, of course, standardized. The main reasons for this were elimination of the sensitization agents in the interim and testing with a less acute skin condition. Allergens that are difficult to avoid, such as the ‘para’ compounds and balsam of Peru and related substances, show a higher degree of persistence in subsequent patch te