[Contact sensitization in leg ulcers].

BACKGROUND

The leading complication of leg ulcers is the development of peri-lesional eczema. The etiological diagnosis is often difficult due to the large number of topical agents used.

METHODS

Fifty patients, 35 women and 15 men, mean age 67.8 years, range 37-91 years, with leg ulcers of variable duration (15 days to 32 years, median 2 years) underwent explorations using the standard EECDRG battery in search of contact allergies. Eighteen potential allergens and the topical agents employed were tested. Readings were made at 48, 72, 96 or 120 hours.

RESULTS

Sensitization rate was 76 p. 100 (90 p. 100 of the patients with a history of contact dermatitis and 50 p. 100 in those without such history). The respective percentages of positive tests were: balm of Peru 40 p. 100, fragrance-mix 28 p. 100, Amerchol L101 18 p. 100, lanoline alcohols 14 p. 100, colophane 12 p. 100, glycol propylene and parabens-mix 8 p. 100, stearylic alcohol, thiomersal, clioquinol and sorbic acid 6 p. 100, cetyl-stearylic alcohol, cetylic alcohol, eosin, cetrimide, chlorocresol, budesonide, tixocortol pivalate, bufexamac, formaldehyde, nickel, thiuram-mix and P.P.D. 4 p. 100, hexamidine, chlorhexidine, neomycin, benzocaine, potassium bichromate and cobalt 2 p. 100, triethanolamine, ethanol and other allergens in the EECDRG battery 0 p. 100. Tests were positive in 29 cases with commercial formulations, Biafine (8 cases), Parfenac (7 cases), and Rifocine ampoules (3 cases). Among 13 of the 29 cases, tests were positive with one or more allergens common to the product and the complementary battery.

CONCLUSIONS

Contact sensitization rate is high in leg ulcer patients. Most of the tests had a relationship with leg ulcers. The number one causal agent is balm of Peru. Thirty percent of all the patients are sensitized to at least one excipient, generally lanoline. Allergy tests are positive in 22 p. 100 for one or more antiseptics and in 18 p. 100 for preservatives. Allergy to latex and neomycin is unusual, but sensitization to steroid anti-inflammatory agents was not tested. The main active ingredient in a topical agent is not always the allergen and a detailed test must be performed, generally with a complementary battery adapted to common prescriptions for leg ulcers.