What substances are tested in the standard “screening” patch test?

Because of its convenience, most patients with a suspected allergic contact dermatitis are patch tested with the True Test “standard” panel of 28 allergens, which can detect many common sensitivities (Table 9-3). However, this panel only detects 62% to 75% of the most common allergens. The North American Contact Dermatitis Group’s Standard 65- allergen tray, which utilizes the Finn Chamber method, is a more efficacious screening series than more limited patch test series. Additional testing with more specialized allergen panels is frequently warranted to enhance allergen detection. Testing should only be done with known materials in accepted concentrations.

Cohen DE, Rao S, Brancaccio RR: Use of the North American Contact Dermatitis Group standard 65-allergen series alone in the evaluation of allergic contact dermatitis: a series of 794 patients, Dermatitis 19:137–141, 2008.

James WD, Rosenthal LE, Brancaccio RR, Marks JG Jr: American Academy of Dermatology Patch Test Survey: use and effectiveness of this procedure, J Am Acad Dermatol 26:991–994, 1992.


Table 9-3. Allergens Evaluated by the True Test and the Finn Chamber Test
  ALLERGEN SOURCES
 
Benzocaine 5%
Topical anesthetic
 
Caine mix
Topical anesthetic
 
Nickel sulfate 2.5%
Metal jewelry
 
Potassium dichromate 0.25%
Leather, cement
 
Cobalt
Metal jewelry, paint
 
Neomycin sulfate 20%
Topical antibiotics
 
p-Phenylenediamine 1%
Hair dye
 
Ethylenediamine 1%
Topical medications
 
Cinnamaldehyde 1%
Perfume, flavors
 
Balsam of Peru 25%
Perfume, medications
 
Fragrance mix
Perfume, flavors
 
Formaldehyde 1%
Preservative, fabric finishes
 
Quaternium-15 2%
Cosmetic and industrial preservative
 
Imidazolidinyl urea 2%
Cosmetic preservative
 
Paraben mix
Cosmetic preservative
 
Thimerosal
Cosmetic and medicament preservative
 
Cl1Me2 Isothiazoline (MCI/MI)
Cosmetic and industrial preservative
 
Lanolin alcohol 30%
Topical skin care products
 
Epoxy resin 1%
Glues, plastics
 
p-tert-butylphenol formaldehyde resin 1%
Glues
 
Colophony (resin) 2%
Adhesives, solder flux
 
Mercaptobenzothiazole 1%
Rubber, fungicide
 
Carba mix 3%
Rubber, fungicide
 
Thiuram mix 1%
Rubber, fungicide
 
Mercapto mix 1%
Rubber, fungicide
 
Black rubber mix 0.6%
Black rubber
 
Budesonide
Topical corticosteroid
 
Tixocortol 21-pivalate
Topical corticosteroid