Histological examination of immediate and delayed contact allergy provoked by mercuric chloride

After smearing her face with a cosmetic bleaching cream, a 40-year-old woman experienced a burning feeling, followed by inflammation and blistering within a few hours. Standard patch tests, 4 weeks after topical and systemic steroid therapy, were negative and only at the site of application of mercuric chloride 0.03% aq. did pruritus and urticaria appear after 20-40 min. The site of this reaction showed eczema on the following days