Objectives: Carboplatin skin testing (ST) can help identify patients with platinum hypersensitivity (PH), however, we have encountered patients who do not immediately test positive yet exhibit subtle or delayed allergy symptoms prior to PH. We describe the "atypical platinum reactions" (APH) of 14 patients and our experience with skin testing and desensitization.
Methods: Retrospective chart review was performed on carboplatin-treated patients. Patients with +ST, PH or APH were offered desensitization, and the number of successful additional treatments was recorded.
Results: A total of 73 ST were administered to patients receiving their >6th carboplatin cycle. 19 +ST and 10 PH with -ST were identified. 14 APH were identified including delayed +ST conversions and allergy symptoms. The median onset and duration of symptoms after treatment were 6 and 3.5 days respectively. 12 APH patients had ST on their next cycle, seven of which were immediately positive. ST was positive in 36% of those tested, resulting in a negative predictive value of 76%. The median number of carboplatin cycles received prior to ST conversion, PH or APH was eight. 29% of patients with a +ST, PH, or APH had a prior history of systemic allergic reaction to other medications or allergens. Desensitization and dose escalation were successful in 14/20 patients (70%) for an average of 1.9 cycles/patient.
Conclusions: ST will not identify all patients with carboplatin-associated reactions. Careful questioning regarding symptoms in between chemotherapeutic cycles may identify patients who will benefit from desensitization, allowing continuation of treatment and prevention of life-threatening adverse events.