Patch screening series

Both Sherertz (1992) and Fowler et al. (1992) examined the records of patients referred to their respective United States clinics to determine how many patients were formaldehyde sensitive. Sherertz found 63 patients who were patch-test positive to formaldehyde or formaldehyde-releasing preservatives. She also found 13 records of patients referred because they had a suspected clothing dermatitis. All 13 had been patch tested with the American Academy screening series and had been evaluated as not being atopic before they arrived at the referral service. Fowler et al. found 678 records of patients referred in a two-year period because they had dermatitis of unknown origin. 

Fowler et al. retrospectively tested the identified patients with the Chemotechnique Diagnostic patch-test series or the Hermal textile series, the North American Contact Dermatitis Group standard screening tray, and other selected allergens. They used Finn Chambers, removed the patches at two days, and read them at 4 days or 7 days. Of the 678 patients, 16 were patch-test positive to textile formaldehyde resins. Formaldehyde-releasing preservatives as well as to textile formaldehyde resins caused allergic reactions in 12 patients. 

Primula dermatitis can be occupational [117], but usually one sees an older housewife with a dermatitis of the fingertips and streaks and patchy eczema on the hands, face [118] (especially the eyelids) [119] and arms [9, 120]. Primula obconica (Fig. 9) is such a common contact allergen in Europe that about i.o-i.8% of persons routinely patch tested react to the causative allergen, primin (0.01% in petrolatum) as part of the European screening series [118]. The eruption may not be suspected until the positive patch test appears [118], and the nondescript pattern may suggest an endogenous cause [118]. Rarely, one sees a reaction to the plant when the patch test to primin is negative [121]. 

Apart from standard and specific screening patch-test series, it is recommended that nonirritant dilutions of workplace substances, such as fresh and used metalworking fluids, barrier creams and soaps and their components, be tested. 

In suspicion of occupational contact dermatitis, the performed patch tests to screen responsible allergens should include appropriate series based on previous experience and information retrieved from safety data sheets. Considering up to date knowledge, in order to screen work-related contact dermatitis beyond stan-... 

The value of patch testing with benzocaine as a screening allergen has been questioned as nearly 70% of allergic reactions to local anesthetics would have been missed with this approach. The authors recommend cinchocaine, which gave the most reactions (50.7%), as a substitute for benzocaine in the baseline patch series [3 ]. 

---