Chronic Hand Eczema, learning from clinical characterization, aetiology, concomitant foot eczema and polysensitization

Supplementary data for the publication: Chronic Hand Eczema, learning from clinical characterization, aetiology, concomitant foot eczema and polysensitization.
Summary: Background. Chronic hand eczema (CHE) is a disabling dermatosis that shows concomitant conditions, such as foot eczema and contact sensitization. Objectives. To identify the characteristics of CHE population in Spain: with special emphasis on occupational dermatitis, evaluation of concomitant foot eczema and of polysensitization phenomenon.Methods. 2,926 patch-tested patients presenting CHE from different specialized Dermatological Units were evaluated. A global descriptive characterization was performed for different subgroups, as well as an evaluation of polysensitization. Results. The first diagnostic for CHE was irritant contact dermatitis (42%) and for patients with foot-and-chronic hand eczema (FCHE) it was allergic contact dermatitis (28%). A 39% of CHE showed occupational relevance. Positivity for at least one allergen was found in 55% of patients, with nickel sulphate and methylisothiazolinone (MI) as the most prevalent. Methylchloroisothiazolinone (MCI)/MI, nickel sulphate and potassium dichromate showed the highest occupational relevance. 236 cases presented concomitant FCHE (8%, 46% men) with higher percentages of positivity for potassium dichromate and cobalt chloride. Twelve percent of patients with CHE were polysensitized, with MI as the most frequent allergen. Conclusions. Patch test for FCHE and CHE shows a specific contact allergen and occupational profile. Methylisothiazolinone appeared as the most related allergen to polysensitization in CHE.