Q:

7/8/2014
I have two patients with true test (level +++) for gold thiosulfate but both of these patients wear gold jewelry and have never had a reaction to it. What am I missing? Can they be allergic to thiosulfate?

A:

Thank you for your inquiry.

Patch tests, like all other tests, have an incidence of both false-positive and false-negative reactions. Patch tests to gold thiosulfate are no exception to this rule. The abstract copied below is a selective illustration of patients who have a positive patch test to gold but can wear gold without difficulty. Also this phenomenon, with special reference to gold thiosulfate, is discussed in the document to which a link is copied below. I have copied below one sentence from this document for your interest, but there are a few paragraphs on the issue of false-positive patch tests to gold which I think will be very helpful to you.

Thank you again for your inquiry and we hope this response is helpful to you.

Contact Dermatitis. 1994 Mar;30(3):144-51.
High frequency of contact allergy to gold sodium thiosulfate. An indication of gold allergy?
Björkner B1, Bruze M, Möller HGold allergy is common, with approximately 10% of patients patch tested because of eczematous disease being positive to gold sodium thiosulfate (GSTS). However, clinical relevance seems to be rare. The aim of this prospective double-blind study was to demonstrate the effects of exposure to metallic gold, in this case earrings, in gold-positive patients. 60 female patients with pierced earlobes test-positive to GSTS were included in the study. The patients were randomized into 2 groups, 30 patients receiving earrings with a surface layer consisting of 24-carat gold and 30 patients earrings with a surface layer of titanium nitride, virtually indistinguishable from gold. The patients wore the earrings for 8 weeks. During the study, any dermatitis on the earlobes, as well as on other body sites, was registered. The skin reactions observed were weak but, in total, 17 of the 60 patients had a skin reaction (local or remote) during the study, 12 of whom had received gold earrings and 5 titanium (p<0.05). 11 patients had a reaction on the earlobes, 7 of whom had received gold earrings and 4 titanium (NS). With these facts it is hard to exclude that exposure to gold jewelry can be clinically relevant in persons hypersensitive to gold.

Re: T.R.U.E Test and gold
"It is well established that a contact allergic reaction to the gold salt, gold sodium thiosulfate (GST), is more common than allergic contact dermatitis to elemental gold or its alloys."

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology