Thoughts on sensitizers in a standard patch test series

Patch testing is the predominant method of establishing contact allergy. Th e present patch test technique is the result of a continuous process of dev elopment and improvement since its first application in the late 19th centu ry. The perfect patch test should give no false-positive and no false-negat ive reactions. The ideal patch test should also cause as few adverse reacti ons as possible, particularly no patch test sensitization. Even though the history and examination of a patient with suspected allergic contact dermat itis will give clues to possible sensitizers, it is not sufficient to patch test only with initially suspected sensitizers; unsuspected sensitizers us ed for patch testing frequently turn out to be the real cause of the dermat itis. Fortunately. a small number of substances are considered to account f or the majority of delayed hypersensitivity reactions. Therefore, generally 20-25 test preparations consisting of chemically defined compounds, mixes of allergens, and natural and synthetic compounds, are grouped into a stand ard test series. The requirements to be fulfilled by a sensitizer in a stan dard patch test series are discussed in this article. A procedure of invest igations is proposed before a sensitizer is included in a standard series.