Beware of contact dermatitis triggered by ICD implants.
Although allergic reactions to implantable cardioverter defibrillators (ICDs) are rare, the rapidly increasing number of patients being given ICDs probably will mean more cases of defibrillator dermatitis. "'We do expect to see more," she said at the annual meeting of the American Contact Dermatitis Society.
During 1996-2001, the number of patients with ICDs increased by 24% annually, noted Dr. Lee-Bellantoni of Tufts-New England Medical Center, Boston.
She described the case of a 57-year-old man with a history of coronary artery disease and myocardial infarction who received an ICD to manage ventricular tachycardia. His first ICD, implanted in 1991, was replaced in 1994 and again in 1997 and 2004. One week after the 2004 ICD was placed in the extraperitoneal space of the man's abdomen, he developed a wound dehiscence near the center of the incision site. He had no fever, chills, or leukocytosis, but developed erythema over the ICD area. The dehiscence healed but the erythema persisted, so he was treated with oral antibiotics for presumed infection. The erythema expanded over the ICD implantation, still with no pain, pruritus, or fever. The patient was hospitalized twice with a diagnosis of infection of the left lower abdomen and was given IV antibiotics, including vancomycin.
During the second hospitalization, the patient came to the attention of dermatologists, who took a tissue biopsy. The results were nondiagnostic but consistent with possible hypersensitivity. Culture was negative for bacteria and fungi.
'Although the cardiologists knew there was something weird going on, they were still essentially worried about infection. But the dermatologists were worried about hypersensitivity reaction," Dr. Lee-Bellantoni said.
The dermatologists obtained an ICD materials test kit from the ICD manufacturer containing materials from the 11 components that come into contact with patient tissue. They patch-tested the patient to the plastics, silicones, epoxies, and other materials in the kit, as well as to a standard group of preservatives, fragrances, and other potential allergens.
The results showed evidence of contact hypersensitivity to polyurethane 75D and peroxide-cured silicone rubber, which were present in the patient's ICD. This information helped cardiologists choose a different ICD for him. After replacement of the offending ICD with the new one in a different location, the erythema gradually resolved.
The cost of the patient's two hospitalizations and antibiotic treatment totalled $9,544. The patch test, which cost $1,286, was "'really cost effective," Dr. Lee-Bellantoni said. Plus, "you really can't overestimate the emotional cost to the patient in terms of stress over the possibility of resistant infection, nosocomial infection, and work time lost."
Suspect contact allergy in the absence of proven infection in a patient with erythema at the ICD site, she suggested.
Amine catalysts used in polyurethanes and epoxy systems as hardeners and curing agents are very strong sensitizers. Polyurethanes and epoxies may be used for surface coatings of various manufactured items.
The patient had a history of exposure to these and other potential sensitizers in his work as a motorcycle shop manager and in previous woodworking environments. Regardless, multiple ICD placements could, by themselves, be enough to sensitize someone to these agents, she said.
There are 30 cases in the literature of hypersensitivity to ICDs or to pacemakers. If a reaction is suspected, a negative patch test does not necessarily rule out sensitization because it is difficult to get a response to the tiny piece of material used in the tests, she cautioned.
San Francisco Bureau
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|Title Annotation:||Cardiovacular Medicine; implanted cardioverter defibrillator|
|Publication:||Family Practice News|
|Date:||Apr 15, 2006|
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