The absorption of benzoyl peroxide from leg ulcers.

Absorption and clinical efficacy of a preparation containing 20% benzoyl peroxide were studied in 20 patients with leg ulcers of varying etiology. Benzoic acid formed from benzoyl peroxide on penetration through the skin cannot be demonstrated in the plasma until three days after commencing application at the earliest. This indicates a building up of deposits of benzoyl peroxide in the skin. The plasma benzoic acid levels in all patients amounted to less than 5 mumol/l and is therefore toxicologically inoffensive. Clinically, the known therapeutic effects of benzoyl peroxide were confirmed. Neither sensitization nor allergic reactions were found in the 20 patients taking part in this study.