e focus of this review are allergic reactions to or-thopaedic surgical metal implants.  e spectrum of metal implant associated potential allergic reac-tions encompasses eczema, impaired wound and fracture healing, infection-mimicking reactions, ef-fusions, pain and loosening. Nickel, cobalt and chromium seem to be the predominant eliciting allergens. Despite the growing number of respective publications the topic „metal implant allergy“ re-mains a diagnostic challenge. Initially, di erential diagnoses should always be excluded in cooperation with surgery collegues. It is= recommended to per-form a combined evaluation of medical history,
clinical  ndings, patch testing and histology.  e lymphocyte transformation test (LTT) can indicate metal sensitization, but it needs careful interpreta-tion. Allergists can provide a substantial contribu-tion to this interdisciplinary topic.