Chemical Leukoderma after Allergic Contact Dermatitis and Patch Testing
Bibliographic record
Abstract
Chemical leukoderma (CL) is an acquired depigmentation condition caused by repeated exposure to melanocytotoxic chemicals that can occur in the presence or absence of allergic contact dermatitis (ACD). Chemicals containing aromatic or aliphatic derivatives such as phenols and catechols have been shown to have melanocytotoxic properties that contribute to the pathogenesis of CL. Lesions are clinically and histologically indistinguishable from vitiligo and can occur in the absence of preexisting inflammatory cutaneous disease or vitiligo. CL often occurs after the use of personal care products or through occupational exposure (such as personal protective equipment). It is a growing phenomenon that has affected patients worldwide and can especially have detrimental psychosocial effects on patients with skin of color because of the sharp contrast between the leukoderma and the background pigmentation of the unaffected skin. A large number of reports of ACD preceding CL in the past five decades suggest that sensitization to allergens containing both aromatic and nonaromatic compounds may be contributory to the development of contact hypersensitivity reaction followed by leukoderma weeks to months after initial exposure. The most commonly reported allergen among these case reports is para-phenylenediamine, an agent used in hair dye and frequently as a darkening agent in henna tattoos. This review provides an overview of the pathophysiology and factors related to CL after ACD or diagnostic patch testing and the allergens related to this disorder of pigmentation.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".