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Allergic contact dermatitis from implanted cardiac devices may be uncommon but typically can be overcome, according to a retrospective study.

Among 11 patients at one large center who underwent cardiac implant patch testing due to concerns of infection, skin symptoms, skin eruption, and concern of allergy, six (55%) had relevant positive patch test reactions, largely to metals (four cases, 36%).

Other positive patch test findings were reactions to lidocaine, silicone, rubber accelerators, and a device-related dexamethasone plug, reported Amber Reck Atwater, MD, of Duke University Medical Center in Durham, North Carolina, and colleagues in .

"Cardiac device allergy should be considered when there is clinical concern for infection, history of device extraction, history of erythema at the implant site, or negative culture results," the study authors wrote.

In their cohort of patients, "[c]oncern for infection was common, and more than half of patients had devices extracted prior to presentation," whereas all but two culture results were negative.

However, they were able to get good results in many of these cases with allergen guidance, they noted.

During reimplantation, electrophysiologists avoided relevant allergens with one exception.

Patients underwent extraction before the first negative patch test and had a new device placed, but symptoms recurred. An alternative device couldn't be identified without the allergens found to be causing the reaction on further testing, so therapy with maintenance prednisone was employed to prevent recurrent reaction.

After reimplantation, the duration of success ranged from 11 to 36 months.

Three of the five patients with negative patch tests kept their implanted cardiac devices, which the researchers said "demonstrated that the negative patch test result had important diagnostic value." The other two had their devices extracted before testing, and there was no indication for reimplantation.

Previous reports have shown various components used in pacemakers and other cardiac devices to have caused skin reactions, although some of those reports were from extra-cardiac devices, the researchers noted.

And prior reports have been mainly limited to case reports, noted Tejesh Patel, MD, a dermatologist of The University of Tennessee Health Science Center in Memphis, who was not involved in the study.

"Reports of allergic contact dermatitis associated with cardiac devices are relatively sparse compared to other biomedical devices, especially orthopedic devices," he told 名媛直播.

He called the findings good news in that "favorable outcomes may be obtained when allergen-guided reimplantation is performed."

Atwater's group collected information from a preexisting database repository. Participants were adult patients at Duke University School of Medicine's Department of Dermatology who underwent cardiac implant patch testing.

The researchers evaluated 11 patients (mean age 58.4, 27% female) who had completed 15 patch test sessions. There were five patients with implantable cardioverter defibrillators and six with pacemakers.

Culture information on the patients who underwent extraction showed that five cultures had negative results. One had a secondary infection, and another had a true infection based on clinical impression, they added.

Limitations included that the study did not have follow-up information for two participants, and the follow-up period was limited to up to 36 months.

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