Patch Testing for Implanted Medical Device-Related Delayed Hypersensitivity Reactions: Retrospective Analysis of...

Medical implants are often suspected of causing allergic reactions.

To determine results for 2016-2022 North American Contact Dermatitis Group implant patch testing.

Retrospective, cross-sectional analysis of clinical findings and patch test results.

Of 128 Pre-implant cases, 57.8% had ≥1 positive patch test reaction (PPTR). Top implant sites were knee and hip (62.7%). Top PPTRs were nickel 5% (43.0%), nickel 2.5% (29.1%), vanadium (14.3%), and cobalt (11%). Of 170 Post-implant cases, 45.3% had no dermatitis, 29.8% had dermatitis at the implant site, and 14.9% had scattered/generalized distribution. Top implant sites were knee and hip (66.8%). There was ≥1 PPTR in 35.9% of patients. 27/43 (62.8%) allergens ever tested positive, and of these, 77.8% (21/27) had current relevance. Top PPTR were nickel 5% (16.5%), nickel 2.5% (12.9%), cobalt (6.5%), and neomycin (5.9%). Of 170 cases, 18 (10.6%) were diagnosed with allergic contact dermatitis at implant site due to implant, with top allergens titanium oxalate (n = 4), tobramycin (n = 3), cobalt (n = 3), and nickel 5% (n = 3).

Over half of Pre-implant and just over 1/3 of Post-implant patients had ≥1 PPTR. About 10% of Post-implant patients were diagnosed with allergic contact dermatitis at implant site due to implant. Outcomes data are needed to confirm relevance.