Table VII.

Relationship between cross-reactions to other para-group chemicals and the grade of patch test reactions to PPDA

Positive reactions to PPDA			Positive reactions to other para group compound, N (%)*
	Grade of reaction to PPDA	N N = 128	IPPD N = 10	TDA N = 0	EDA N = 0	TETA N = 1	Paraben mix N = 8	Benzocaine N = 18
1	+	53	3 (5.7)	0	0	1 (1.9)	3 (5.6)	4 (7.5)
2	++	42	4 (9.5)	0	0	0	3 (7.1)	5 (11.9)
3	+++	33	3 (9.4)	0	0	0	2 (6.4)	9 (27.3)
			NS			NS	NS	1 vs. 3, p = 0.013#

^*Percentage calculated in relation to the total number of positive reactions to PPDA of the respective grade.

PPDA – paraphenylenediamine, IPPD – N-isopropyl-N-phenyl-4-phenylenediamine, TDA – toluene-2,5-diamine, TETA – triethylenetetramine, EDA – ethylenediamine.