Contact allergens in patients with leg ulcers

Background Contact dermatitis can complicate the treatment of leg ulcers and is an acquired phenomenon resulting from the use of topical medications.

Objective To show the incidence of contact dermatitis reactions to topical medications applied to leg ulcers and to evidence changing trends in such reactions through comparison of two case series about 20 years apart.

Subjects and methods We studied two groups of patients with leg ulcers that were patch tested with contact allergens in 1973–1974 and in 1994–1995.

Results One or more positive patch tests was present in 75% and 40% of the patients, respectively. A decrease in the incidence of positive reactions to neomycin, local anesthetics and parabens mix was seen in 1994–1995. The most important contact allergens in 1994–1995 were fragrance mix, colophony and the excipients wool alcohols and amerchol. Other relevant sensitizers were formaldehyde, neomycin and gentamycin.

Conclusion The changing trends in contact allergens over the last 20 years may be explained by changes in the components of topical agents used for treatment.