Contact sensitization in chronic venous insufficiency: modern wound dressings.

Patch tests with an expanded European standard series and 20 different wound dressings revealed sensitization in 78% of all (36) patients. The charts of allergens were headed by ointment bases (wool wax alcohols sensitization in 33% of all patients; Amerchol L-101 19.4%; cetearyl alcohol 13.9%; propylene glycol 8.3%), followed by plant resins/ethereal oils (balsam of Peru 22.2%; colophony 13.9%, fragrance mix 8.3%; propolis 5.6%) and topical antibiotics (neomycin sulfate 16.7%, chloramphenicol 13.9%), while usually common sensitizers like metal salts were not found as often (nickel sulfate 16.7%; potassium dichromate 13.9%; cobalt chloride 5.6%). Sensitization to modern wound dressings was found in 8.3% (3 cases) and was caused by propylene glycol as an ingredient of hydrogels; no sensitization was found to hydrocolloids, alginates or polyurethane foams. The overall sensitization rate in 2nd degree CVI was nearly as high as in 3rd degree CVI, but sensitization to ointments, their additives and topical antibiotics was significantly higher in 3rd degree CVI. Significant differences in sensitization frequencies to individual allergens were found between male and female patients. Our investigation points out the high risk of sensitization in 2nd as well as 3rd degree CVI, especially to ointment bases and active principles of topical drugs. Even wound dressings may cause allergic contact reactions.