Papular dermatitis and a persistent patch test reaction to gold sodium thiosulfate

Abstract

The role of gold in allergic contact dermatitis is poorly understood and is a subject of increasing interest. Recent studies demonstrate that gold-positive patch testing is not uncommon, but persistent patch test reactions are rarely reported. We present a case of a 53-year-old woman with a 7-year history of a scattered, pruritic papular dermatitis. Patch testing demonstrated a persistent, positive reaction to gold sodium thiosulfate. The histopathology of the patch test site and that of the cutaneous eruption were similar in nature but differing in severity. No other allergens have been identified, but gold avoidance has not yet resulted in the clearing of her eruption. This case underscores the difficulty in making a clinical correlation despite suggestive clinical pathologic evidence.

European Society of Contact Dermatitis guideline for diagnostic patch testing – recommendations on best practice

“…Gold chloride 0.5% aq. is notorious for causing persisting reactions (1,144). Palladium tetrachloride has been reported to cause persisting granulomatous patch test reactions (145,146).…”

Patch test reaction to p‐phenylenediamine can persist for more than 1 month

“…Our case showed the concomitant occurrence of a long‐lasting allergic patch test reaction and a flare‐up reaction. It has been suggested that long‐lasting allergic patch test reactions are not as infrequent as suspected, because they are not expected by the clinician . Our case implies a possible relationship between a long‐lasting allergic patch test reaction and a flare‐up reaction in allergic contact dermatitis with widespread skin lesions.…”

Cutaneous pseudolymphoma after patch test to gold sodium thiosulfate in two patients

“…CPsL secondary to gold has been described at the site of piercing and following intradermal testing, acupuncture, and eyelids implants. With regard to patch tests, a pseudolymphomatous reaction with persistent exposure to GST has been described in a few previous reports, although immunohistochemical techniques were not always employed . Likewise, one case of CPsL has been recently reported in a long‐lasting allergic patch test reaction with topical minoxidil 5% .…”