Sickle Cell Pain: Intervention With Capsaicin Exposure

Patients with sickle cell disease suffer debilitating painful episodes, as well as chronic, often daily, pain that are commonly treated with non-steroidal anti-inflammatory drugs, opioids, and other non-pharmacologic supportive measures. Neuropathic pain has been shown to be present in these patients, with frequency increasing with age. It is believed, based on knowledge of neuropathic pain related to other conditions and from the small number of studies in sickle cell patients, to result from repeated vaso-occlusive pain episodes that prime central and peripheral pain sensing pathways in a maladaptive manner, leading to hyper-sensitization. Very few studies to date have evaluated therapies specifically targeting this aspect of the pain experienced by patients with sickle cell disease. This is a pilot study for a future longitudinal study of neuropathic pain in pediatric patients with sickle cell disease. The first aim of this pilot study is to establish the safety of treating participants with sickle cell disease aged fourteen to twenty-one with eight percent topical capsaicin patches on an every three-month dosing schedule as recommended by the manufacturer. This will be a single-arm safety study. Presence of neuropathic pain will be determined by day zero evaluation via the testing shown in the outcome measures below. Topical medication will be administered over one hour, every three months, for six months (total of three applications), to sites of recurrent vaso-occlusive pain, according to the package insert administration guidelines. Subjective and objective evaluations of pain and inflammation including questionnaires, blood tests, and quantitative sensory testing will be carried out every six weeks throughout the study period until twelve weeks after the final capsaicin application. Additionally, participants will record daily pain and medication use in a mobile app. Safety will be established by there being no grade three or four adverse events according to CTCAE definitions. Grade two adverse events will be evaluated on a case by case basis throughout the duration of the study. Feasibility of monitoring neuropathic pain with the aforementioned studies will be established by participant compliance with greater than eighty percent of all study activities.