A 10-Year Review of p-Phenylenediamine Allergy and Related para-Amino Compounds at the Ottawa Patch Test Clinic
Bibliographic record
Abstract
BACKGROUND: p-Phenylenediamine (PPD) is an important allergen; 5.0% of patients tested positive to PPD when patch-tested, according to the North American Contact Dermatitis Group. Hair dyes are the main source of exposure. OBJECTIVE: To assess the significance of PPD allergy at the Ottawa Patch Test Clinic. METHODS: We assessed the epidemiology of PPD allergies and determined the cross-reactivity with other para-amino compounds. Charts of patients visiting the Ottawa Patch Test Clinic between May 1997 and July 2009 were reviewed. RESULTS: One hundred thirty-four patients were found to have a contact allergy to PPD; 75.4% were female, 24.6% were male, 13.4% were hairdressers, 18.7% had a history of atopy, 90.3% were sensitized by hair dye, 2.2% were sensitized by henna tattoos, and 7.5% were sensitized by other sources. Positive patch-test reactions to textile dyes were seen in 24.6%, 7.5% reacted to benzocaine, 6.0% reacted to sulfa drugs, 1.5% reacted to isopropyl-para-phenylenediamine, and 1.5% reacted to para-aminobenzoic acid. CONCLUSIONS: PPD is an important source of allergic contact allergy. Our results show a significant relationship of PPD with other related para-amino compounds.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.010 | 0.010 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".