“…There is no general consensus regarding which mercury compounds to use for patch testing patients with suspected mercury allergy. Problems arise as (a) most mercury compounds, especially mercuric chloride and thimerosal, are highly irritant (9, 10), (b) aqueous solutions of mercury salts can react with aluminium in Finn Chambers to produce irritant compounds (11,12), and (c) the degree of cross-reactivity between different inorganic and organic mercury compounds is uncertain (10,(13)(14)(15)(16). The North American Contact Dermatitis Group (NACDG) recommends patch testing only with ammoniated mercury (17), but others also test with metallic mercury (10,13), ground-up amalgam (2), thimerosal (10,13), and mercuric chloride (9,10).…”