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The risk of active sensitization to PPD
Author(s) -
Devos Steven A.,
Van Der Valk Pieter G. M.
Publication year - 2001
Publication title -
contact dermatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 96
eISSN - 1600-0536
pISSN - 0105-1873
DOI - 10.1034/j.1600-0536.2001.440503.x
Subject(s) - sensitization , medicine , allergic contact dermatitis , dermatology , allergy , skin test , immunology , tuberculosis , pathology
Para‐phenylenediamine (PPD) and para‐aminoazobenzene are strong sensitizers. By the patch test procedure, the patient may be sensitized to these agents. Combined testing of para‐compounds may increase the risk of active sensitization. We studied the % of positive patch test reactions and their relevance. In order to assess the risk of active sensitization, we compared the % of relevant reactions of both early (2/3 days) and late (7 days) reactions. We also compared the percentage of positive patch test reactions to PPD and their relevance if simultaneously tested with para‐aminoazobenzene. We studied the patch test reactions to PPD in the routine series in 2058 patients. In a group of 678 patients we tested PPD and para‐aminoazobenzene simultaneously. 4.3% and 3.1% of the patients reacted to PPD, respectively, with and without simultaneous testing with para‐aminoazobenzene. We estimated the reactions as relevant in 21.1% and 39.7%, respectively, with and without simultaneous testing with para‐aminoazobenzene. We considered none of the late reactions as relevant. We found a high proportion of relevant patch test reactions to PPD, but sensitization to PPD by the patch test procedure is a risk. We state that routine series should not contain PPD. The high number of irrelevant late positive reactions strongly suggests active sensitization. Moreover, PPD is not a ubiquitous allergen and can be tested on a non‐routine basis if industrial exposure to para‐compounds is suspected or if a specific localization (e.g., head or feet) prompts the testing of PPD. Testing PPD combined with para‐aminoazobenzene does lead to a slight increase in positive reactions to PPD ( p <0.25) and to an increase in irrelevant reactions ( p <0.10).