Gollhausen et aL

Journal of the American Academy of

Dermatology

Only fur ther studies of the reproducibility of patch test reactions will help to assess the accuracy of the different test systems.

REFERENCES 1. Lachapelle JM, Bruynzeel DP, Dueombs G, et al. Eu-

ropean multicenter study of the TRUE Test. Contact Dermatitis 1988;19:91-7.

2. Gollhausen R, Przybilla B, Ring J. Reproducibility of patch testing. Proceedings of the XVII Congressus Mundi Der- matologiae, Berlin, May 24-29, 1987.

3. Bandmann H J, Dohn W. Die Epikutantestung. Mfinchen: Bergmann, 1967.

4. Fischer T, Maibach HI. The thin layer rapid use epicuta- neous test (TRUE Test), a new patch test method with high accuracy. Br J Dermatol 1985;112:63-8.

5. Fischer T, Maibach HI. Patch test allergens in petrolatum: a reappraisal. Contact Dermatitis 1984;11:224-8.

6. Fischer T, Rystedt I. False positive, follicular and irritant patch test reactions to metal salts. Contact Dermatitis 1985;12:93-8.

7. Fischer T, Maibaeh HI. Patch testing in allergic contact dermatitis: an update. Semin Derrnatol 1986;5:214-24.

8. Bruynzeel DP. Angry back or excited skin syndrome [The- sis]. Amsterdam: Kripps, 1983.

9. Kligrnan AM, Gollhausen R. The "angry back," a new concept or old confusion? Br J Dermatol 1986;115(suppl 31):93-100.

10. HasanT~JansenCT. Repreducibilityand dosagingin pho- tocontact testing. Presented at the European Symposium on Contact Dermatitis, Heidelberg, W Germany, May 27-29, 1988.

III II I

Comparative multicenter studies with TRUE Test and Finn Chambers in eight Swedish hospitals T R U E Test S tudy Group*

A multicenter study with the TRUE Test standard panel and the same allergens in petro- latum applied with the Finn Chamber technique indicated 167 positive reactions with both test methods. Thirty-eight positive reactions were indicated with TRUE Test alone and 28 positive reactions were indicated with the Finn Chamber method only. Irritant reactions were equally frequent with both tests. Quality, as scored by surface distribution and adherence of the tape, tended to be slightly better with TRUE Test. Less than 50% of the positive test re- suits were predicted by history, whereas morethan 75% of them had past or present relevance. (J AM ACAD DERMATOL 1989;21:846-9.)

The T R U E Test (Pha rmae ia AB, Uppsala, Swe- den) is manufac tu red by incorporating allergens in different cellulose gels. a The reference material was commercial ly available, s tandard allergens in petro- la tum recommended by the Internat ional Contact Dermatitis Research Group except for Kathon C G 0.02% in water. Allergens were also applied with the Finn Chamber technique.

Reprint requests: Margit Ruhnek-Forsbeck, MD, Department of Der- matology, Srdersjukhuset, Box 38 100, S-100 64 Stockholm, Swe- den.

*Members of the TRUE Test Study Group are as follows: Margh Ru- hnek-Forsbeek, MD, S&tersjukhuset; Torkel Fischer, MD, Uppsala; Birgitta Meding, MD, G6teborg; Leif Nordin, MD, GSteborg; Lars Pettersson, MD, G~vle; Berndt Stenberg, MD, Um~; Karin Sund- berg, MD, Linkrping; Louise Svensson, MD, G~vle; Gunnar Swan- beck, MD, Grteborg; Jan E. Wahlberg, MD, Stockholm; Lena Widstr6m, MD, Orebro; and Karin Wrangsj~, MD, Stockholm.

1~/o/1292o

METHODS Patients

Two hundred forty-eight patients with past or present contact dermatitis were tested with T R U E Test panel 12'3 and 367 patients were tested with panel 2. 4

Test method

The two test strips were applied symmetrically on the upper back. The left-right application of each test varied at random. The patches were removed after 48 hours and most tests were evaluated at 72 or 96 hours. Relevance, preference, and side effects were recorded. The number of positive test reactions served as a quality score.

RESULTS

Panel 1 consists of 12 different allergens or mixes (Table I). Two hundred forty-five patients were

846

Volume 21 Number 4, Par t 2 October 1989 TRUE Test patch test system." Results from Sweden 847

Table I. Panel 1 allergens

1. Nickel sulfate hexahydrate 2. Paraphenylenediamine

dihydrochloride 3. Neomycin sulfate 4. Potassium dichromate 5. Caine mix

Benzoeaine Dibucaine hydroehloride Tetracaine hydrochloride

6. Fragrance mix Cinnamyl alcohol Cinnamaldehyde Alpha-amyl-einnamaldehyde Isoeugenol Hydroxycitronellal Eagenol Geraniol Oak moss absolute

7. Colophony 8. Epoxy resin 9. Thiuram mix

Tetramethylthiuram monosulfide Tetramethylthiuram disulfide Disulfiram Diphentamethylenethiuram disulfide

10. Balsam of Peru 11. Ethylenediamine dihydroehloride 12. Cobalt chloride hexahydrate

evaluated at 72 or 96 hours. There were reactions among the patients for each of the 12 allergens in- cluded. No patient was dropped from the study due to side effects. In 98 individuals, 156 allergens gave positive (I + to 3+) reactions to one or both test methods (Fig. 1). In 121 reaction pairs both tests caused positive reactions, 16 were positive only on the TRUE Test, and 19 were positive only with Finn Chambers. Fig. 2 shows that irritation and question- able reactions appeared equally frequently with both tests. Irritant reactions were more frequent to po- tassium dichromate in the Finn Chambers, whereas with TRUE Test method such reactions were more frequent for cobalt chloride. Discrepancies between the tests concerning colophony and balsam of Peru may be explained by the fact that these substances are of biologic origin and therefore not well defined.

Panel 2 consists of 11 different allergens or aller- gen mixes (Table II). Three hundred sixty-seven patients completed the study and none left the study due to side effects (Fig. 3). Each of the 11 allergens caused reactions in the test population; 77 pairs of tests resulted in positive (1 + to 3+) reactions in ei- ther or both of the tests. Forty-six positive reactions were indicated with both tests. Concordance was

No of reactions

45. r'l

40.

35

30

25.

20.

15.

I ta~

~ = T T ÷

~=TT +%+++ [i]°Fc ÷ [-]=FC+ +,+ ++

3 4 5

i-I

1 2 7 S 9 10 11 .1'2 Allergen

Fig. 1. Positive reactions in 245 patients tested with the TRUE Test (TT) and with Finn Chambers (FC),

No of reactions

N] = T T IR/? [] = FC IR/?

25.

20-

15-

10-

5" ~ [W. 1

1 2 8 4 5 6 7 8 9 10 l l 12

Allergen

Fig. 2. Irritant and questionable reactions in 245 pa- tients tested with the TRUE Test (TT) and with Finn Chambers (FC).

60%. Twenty-two (28%) positive results were in- dicated only by TRUE Test and nine (12%) were indicated only with Finn Chambers. Thimerosal caused irritant or questionable reactions signifi- cantly more often in TRUE Test, and the dosage of

848 Ruhnek-Forsbeck et aI.

Journal of the American Academy of

Dermatology

No of reactions

~=TT + []--TT ++,+++

15. r--, , , = 1 ~ 0 +

E]=FC ++,+++

10

| m m •

13 14 • • , , i ,

15 16 17 18

--12-1 N, I I

u • m m ! u

19 20 22 23

F'q

~ A12ergen i i y

24

Fig. 3. Positive reactions in 367 patients tested with the TRUE Test (TT) and with Finn Chambers (FC).

Table II. Panel 2 allergens

13. p-tert-Butylphenol formaldehyde resin 14. Parabens

Methyl parahydroxybenzoate Ethyl parahydroxybenzoate Propyl parahydroxybenzoate Butyl parahydroxybenzoate Benzyl parahydroxybenzoate

15. Carba mix 1,3-Diphenylguanidine Zinc diethyldithioearbamate Zinc dibutyldithiocarbamate

16. Black rubber mix N-Cyclohexyl-N'-phenyl-

paraphenylenediamine N-Isopropyl-N'-phenyl-

paraphenylenediamine N,N'-Diphenyl-paraphenylenediamine

17. Kathon CG 18. Quarternium 15 19. Mercaptobenzothiazole 20. Wool alcohols 21. Negative control 22. Mercapto mix

Morpholinylmercapto-benzothiazole N-Cyclohexylbenzothiazyl-sulfenamide Dibenzothiazyl disulfide

23. Thimerosal 24. Quinoline mix

Choquinol Chlorquinaldol

this allergen was subsequently adjusted (Fig. 4). For all other substances, the frequency of such reactions was similar or lower for TRUE Test than for Finn Chambers.

The best test quality is obtained when the reaction

Table IlL Tape adhesiveness

TRUE Test [ Finn Chamber

Per~ct 568* 537 Notperfect 44 75

TOTAL 612 612

*p < 0.01 compared with Finn Chamber.

covers the whole area tested _+ 20%. A test covering less than 80% should arouse suspicion of irritancy, whereas coverage above 120% can cause a spillover effect, which may produce irritant reactions in adja- cent tests. Widespread reactions are more common with petrolatum tests than with TRUE Test because of an effiux of test material around the test site, of- ten due to an incorrect dose. TRUE Test reactions are mostly within the limits of the patch size.

Tape adhesiveness was significantly better for TRUE Test than for Finn Chambers (Table III). Tape adhesiveness was perfect in 89% for T R U E Test and 86% for Finn Chambers in panel 1. For panel 2 the corresponding values are 95% and 89%.

Irritation caused by the tape was rare, and no difference was noted between the two test meth- ods.

It is very important to identify the causative allergen by testing. In panel 1 the suspicion of allergy aroused by history could be verified in about 50% of the reactions, whereas a posttest history verified rel- evance in 77%. In panel 2 the test reactions con- firmed suspicion by history in only 30% of cases. This difference might be expected, as the substances of this panel cause contact dermatitis less frequently.

Volume 21 Number 4, Part 2 October 1989 TRUE Test patch test system: Results from Sweden 849

No of reactions

15.

[~]=TT IR/? [::]--FC ~ / ?

10 .

, ~ Allergen

, , ,1~6~ ,17 ,18, 1~1~9~ ,201~, , , , , , -~ 13 14 22 23 24

Fig. 4. Irritant and questionable test reactions in 367 patients tested with the T R U E Test (TT) and with Finn Chambers (FC).

Patch testing m a y cause sensitizing. This risk is small, however, provided that the allergen dose is adequate. It has been shown that the risk of sensiti- zation correlates bet ter with the concentration of al- lergen per square area than with the size of the area exposed to allergen. 6 It may therefore be an advan- tage to use T R U E Test, with its smaller amount of allergen per area unit.

CONCLUSION

This study indicates that the T R U E Test is a well-standardized technique with few side effects. It is easy to handle and gives good accuracy.

REFERENCES 1. Fischer T, Maibach HI. The thin.layer rapid-use epicu-

taneous test (TRUE Test), a new patch test method with high accuracy. Br J Dermato11985;112:63-8.

2. Lachapelle J-M. European multicenter study of TRUE Test. Contact Dermatitis 1988;19:91-7.

3. Ruhnek-Forsbeck M, Fischer T, Meding B, et al. Compar- ative multi-center study with TRUE Test and Finn Cham- ber patch test methods in eight Swedish hospitals. Aeta Derm Venereol (Stockh) 1988;68:123-8.

4. Stenberg B, et al. A comparative multicenter study with TRUE Test: Panel 2 and Finn Chamber patch test methods in eight Swedish hospitals. (To be published.)

5. Fischer T, Maibach HI. The science of patch test standard- ization. In: Maibach HI, ed. Immunology and allergy clin- ics. Philadelphia: WB Saunders, 1988.

6. White $1, Friedmann PS, Moss C, et al. The effect of alter- ing area of application and dose per unit area on sensitiza- tion by DNCB. Br J Dermato11986;115:663-8.