Patch test results in patients with suspected contact allergy to shoes: Retrospective IVDK data analysis 2009–2018

Background Allergic contact dermatitis caused by shoes is common and new relevant allergens have been identified. Objectives To investigate the pattern of type IV sensitization in patients with suspected allergic contact dermatitis of the feet related to shoes as a presumed culprit trigger. Methods Retrospective analysis of data of the Information Network of Departments of Dermatology (IVDK), 2009‐2018. Results Six hundred twenty‐five patients with presumed shoe dermatitis were identified in a cohort of 119 417 patients. Compared to patients with suspected contact sensitization from other allergen sources (n = 118 792), study group patients were more frequently sensitized to potassium dichromate (10.8% vs 3.5%), colophony (7.2% vs 3.7%), mercaptobenzothiazole (MBT; 4.0% vs 0.6%), mercapto mix (4.6% vs 0.6%), and p‐tert‐butylphenol formaldehyde resin (1.6% vs 0.5%). Sensitizations to urea formaldehyde resin, melamine formaldehyde resin, glutaraldehyde, tricresyl phosphate, and phenyl glycidylether were rare. Moreover, reactions to compounds in the leather or textile dyes test series were scarce. Conclusion A distinct sensitization pattern was observed in patients with suspected allergy to shoe materials. Although substances with low sensitization rates should be removed from the leather and shoe patch test series, novel potential allergens should be added. Patients with suspected shoe dermatitis were more frequently sensitized to potassium dichromate, colophony, mercaptobenzothiazole (MBT), mercaptomix, and p‐tertbutylphenol formaldehyde resin (PTBP‐FR). Sensitizations to urea formaldehyde resin, melamine formaldehyde resin, glutaraldehyde, tricresyl phosphate, and phenyl glycidylether were rare. Patch test recommendations for patients with shoe dermatitis should be revised on the basis of this data and recent publications.