Evidence‐based diagnosis in patch testing

Abstract

Evidence-based medicine (EBM) is defined as the integration of the best research evidence with clinical expertise and patient values. Based on the principles of EBM, we can conclude that patch testing is cost-effective only if patients are selected on the basis of a clear-cut clinical suspicion of contact allergy and only if patients are tested with chemicals relevant to the problem (high pretest probability). Random patch testing (low pretest probability) should be discouraged. Proper pretest probability assessment can only be done in expert centres, because problem-based testing requires both a thorough knowledge of the patch-test procedure and knowledge about potential sensitizers in a specific environment.

Sensitivity to implant materials in patients with total knee arthroplasties

“…Moreover, sensitization occurs in genetically predisposed subjects [7], and it is reasonable to assume that a positive skin reaction reflects the susceptibility to the immunopathological response irrespective of the source of the immunogens. An appropriate panel of haptens taking into account the prosthesis components may improve the helpfulness of patch testing in detecting the sensitization to implant materials [19,20]. With this aim, we used a series of 20 haptens, including the most important components used for the manufacturing of knee arthroplasty.…”

“…Although patch testing is the most common method used to diagnose contact allergy to metals, its validity in determining a deep-tissue hypersensitivity lets some doubts [10,11]. Nevertheless, its usefulness in detecting the sensitization to implant materials may be improved if patients are tested with an appropriate series of haptens according to the prosthesis components [19,20].…”

A Practical Guide to Patch Testing

“…Past relevance is considered if the PT is positive but the exposure was in the past, and not the present. 25,26 Relevance has been shown to vary with allergens. For example, CAPB shows 89.2% present relevance, 27 whereas thimerosal showed present relevance in only 7.3% of cases, likely because sensitization occurred during childhood vaccination.…”

Dermatitis de contacto por el calzado: una actualización

“…Una buena prueba de parche indica una sensibilización por contacto de relevancia pasada o presente y no produce reacción falsa. Sobre la base de los principios de la medicina basada en la evidencia, esta prueba es rentable sólo si los pacientes son seleccionados en los fundamentos de la sospecha clínica de alergia de contacto y solo si los pacientes son examinados con productos químicos relacionados con el problema 26 . Una pequeña cantidad de alérgeno sospechoso se aplica sobre la piel durante un tiempo determinado 20 .…”