Gold is a sensitizer in certain circumstances. Gold should be tested in dental cases and in cases of eyelid and/or facial dermatitis or when jewelry allergy is suspected, especially in piercings. Testing should also be considered when there is dermatitis of the ears, hands, or neck. Gold should also be tested in potential occupational exposure. Testing gold is best performed with gold sodium thiosulfate 2.0% petrolatum. If the test is negative but a strong suspicion is present, the test concentration can be raised to 5.0% petrolatum. Reading of patch tests to gold is necessary both on day 3 or 4 and on day 7 not to miss contact allergy. Sometimes allergic reactions show up even later, up to 3 weeks after patch testing, without being a sign of patch test sensitization. When consecutive dermatitis patients have been tested to gold, the frequency of contact allergy has been high, around 10–15%. In dental patients with dental gold, the frequency is even higher. The clinical relevance of gold allergy in most dermatitis patients is rather low, but in dental patients and in stented patients having received a gold stent, it has been high. Gold allergy is correlated to dental gold, and the more dental gold a patient has, the higher the level of gold in blood.